for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> AGRICULTURE (Total: 711 journals)
    - AGRICULTURAL ECONOMICS (72 journals)
    - AGRICULTURE (484 journals)
    - CROP PRODUCTION AND SOIL (91 journals)
    - DAIRYING AND DAIRY PRODUCTS (25 journals)
    - POULTRY AND LIVESTOCK (39 journals)

AGRICULTURE (484 journals)            First | 1 2 3 4 5     

The end of the list has been reached. Please navigate to previous pages.

  First | 1 2 3 4 5     

Journal Cover   Livestock Science
  [SJR: 0.715]   [H-I: 69]   [6 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1871-1413
   Published by Elsevier Homepage  [2745 journals]
  • Variables of gait inconsistency outperform basic gait Variables in
           detecting mildly lame cows
    • Abstract: Publication date: Available online 20 April 2015
      Source:Livestock Science
      Author(s): A. Van Nuffel , W. Saeys , B. Sonck , J. Vangeyte , K.C. Mertens , B. De Ketelaere , S. Van Weyenberg
      To support herdsmen in finding the lame cows on their herds, several automated systems that measure lameness related cow features such as gait patterns, are being developed. Most of these systems are able to distinguish between non-lame and severely lame cows. Detecting mildly lame cows in an early stage of lameness however seems challenging. Inspired by the approach used in human gait research, new variables that measure the inconsistency in stride-to-stride variables were tested using cow gait and were able to show differences between a group of non-lame and a group of mildly lame cows. In order to investigate the added value of these inconsistency variables in detecting mildly lame cows, two new lameness detection models were build: one using solely basic gait variables and a second model using both basic and the new gait inconsistency variables. The second model using the gait inconsistency variables outperformed the model based on only basic gait variables by far in detecting the mildly lame cows with a sensitivity of 88% and a specificity of 87%. These results support the suggestion of incorporating such gait inconsistency variables into lameness detection models. Further validation of these gait inconsistency variables should be investigated using longitudinal studies where cows developing lameness and recovering from it are monitored daily.


      PubDate: 2015-05-04T10:18:35Z
       
  • Genomic selection for boar taint compounds and carcass traits in a
           commercial pig population
    • Abstract: Publication date: April 2015
      Source:Livestock Science, Volume 174
      Author(s): Carolina Filardi de Campos , Marcos Soares Lopes , Fabyano Fonseca e Silva , Renata Veroneze , Egbert F. Knol , Paulo Sávio Lopes , Simone E.F. Guimarães
      This study aimed to compare two different Genome-Wide Selection (GWS) methods (Ridge Regression BLUP − RR-BLUP and Bayesian LASSO − BL) to predict the genomic estimated breeding values (GEBV) of four phenotypes, including two boar taint compounds, i.e., the concentrations of androstenone (andro) and skatole (ska), and two carcass traits, i.e., backfat thickness (fat) and loin depth (loin), which were measured in a commercial male pig line. Six hundred twenty-two boars were genotyped for 2,500 previously selected single nucleotide polymorphisms (SNPs). The accuracies of the GEBV using both methods were estimated based on Jack-knife cross-validation. The BL showed the best performance for the andro, ska and loin traits, which had accuracy values of 0.65, 0.58 and 0.33, respectively; for the fat trait, the RR-BLUP accuracy of 0.61 outperformed the BL accuracy of 0.56. Considering that BL was more accurate for the majority of the traits, this method is the most favoured for GWS under the conditions of this study. The most relevant SNPs for each trait were located in the chromosome regions that were previously indicated as QTL regions in other studies, i.e., SSC6 for andro and ska, SSC2 for fat, and SSC11, SSC15 and SSC17 for loin.


      PubDate: 2015-05-04T10:18:35Z
       
  • Prospection of genomic regions divergently selected in cutting line of
           Quarter Horses in relation to racing line
    • Abstract: Publication date: April 2015
      Source:Livestock Science, Volume 174
      Author(s): Natalia Andrea R. Beltrán , Camila T. Meira , Henrique N. de Oliveira , Guilherme L. Pereira , Josineudson Augusto II V. Silva , Marcílio Dias S. da Mota , Rogério A. Curi
      The objective of this study was to identify genomic regions divergently selected in the cutting line of Quarter Horses in relation to the racing line using SNP genotyping arrays and the relative extended haplotype homozygosity (REHH) test, an extension of EHH analysis, and the fixation index (F ST) as statistical methods. A total of 188 horses of both sexes, born between 1985 and 2009 and registered with the Brazilian Association of Quarter Horse Breeders (ABQM), were used. Of these, 68 horses were from the cutting line and 120 from the racing line. On the basis of 36 genomic regions classified as selection signatures by the two statistical methods, functional annotation of genes was performed in order to identify those that might have been important during formation of the cutting line. Forty-five genes were found to be involved in biological processes related to the muscle, skeletal, cardiovascular, respiratory and nervous systems, neurotransmission, muscle energy metabolism, motor activity, vision, hearing, and cognitive function. The genes related to the last four processes are particularly interesting because these genes together may be involved in cow sense or cutting ability.


      PubDate: 2015-05-04T10:18:35Z
       
  • Editorial Board
    • Abstract: Publication date: April 2015
      Source:Livestock Science, Volume 174




      PubDate: 2015-05-04T10:18:35Z
       
  • Association of natural (auto-) antibodies in young gilts with
           osteochondrosis at slaughter
    • Abstract: Publication date: Available online 2 April 2015
      Source:Livestock Science
      Author(s): D.B. de Koning , E.P.C.W. Damen , M.G.B. Nieuwland , E.M. van Grevenhof , W. Hazeleger , B. Kemp , H.K. Parmentier
      Osteochondrosis (OC) develops at a young age and has been associated with lameness and reduced longevity of sows. Early detection of OC is therefore beneficial for selection against OC. Possibly, immunological components within the blood may serve as an indicator for OC development and could therefore be used as a biomarker. Levels of naturally occurring (auto-) antibodies (N[A]Ab) have been associated with homeostatic imbalance and various forms of inflammation, and may have an association with OC. The aim of this study was to investigate possible associations between the presence and levels of N(A)Ab of the IgM and IgG isotypes at an early age with OC in growing gilts at slaughter (24 weeks of age). Plasma samples were obtained from 212 Topigs 20 (Dutch Large White x Dutch Landrace) gilts at 6, 10, and 24 weeks of age and analyzed for N(A)Ab titers against 11 (auto-) antigens using ELISA. After slaughter, the elbow, hock, and knee joints were macroscopically examined for OC status. Due to low prevalence of OC in the elbow joint (5.4%), the elbow joint was not taken into account in analyses. Significant (P≤0.05) associations with OC in both the hock joint and at the animal level (all joints combined) were found for IgM titers against chondroitin sulfate A at 6 weeks of age (OR 1.4 and 1.5), actin at 6 weeks of age (OR 1.4 and 1.3), thyroglobulin at 24 weeks of age (OR 1.5 and 1.3), and IgG titers against insulin at 6 weeks of age (OR 1.7 and 1.4). Additionally, significant (P≤0.05) associations with OC were found at the knee joint for IgM titers against albumin at 6 weeks of age (OR 2.3), at the hock joint for IgM titers against keyhole limpet hemocyanin at 6 weeks of age (OR 1.4), and at the animal level for IgM titers against actin at 24 weeks of age (OR 1.3). This study indicated for the first time associations between the presence and levels of N(A)Ab at a young age and OC at 24 weeks of age in breeding gilts.


      PubDate: 2015-05-04T10:18:35Z
       
  • Modeling breed additive and non-additive genetic effects using a Angus x
           Nellore crossbred population
    • Abstract: Publication date: Available online 2 April 2015
      Source:Livestock Science
      Author(s): Claudia Damo Bertoli , Jose Braccini , Connie McManus , Jaime Araujo Cobuci , Elisandra Lurdes Kern , Mario Luiz Piccoli , Flavio Schenkel , Vanerlei Roso
      The objectives of this study were to estimate fixed genetic (both additive and non-additive) effects and test different non-additive models. These effects included direct and maternal joint breed additive effects, direct and maternal complementarity (or profit heterosis), direct and maternal heterosis (dominance) and direct and maternal epistatic loss non-additive effects. A large crossbred Angus x Nellore population with approximately 300,000 records for weaning gain (WG) and 150,000 records for post-weaning gain (PG) was used. Phenotypic scores for weaning (WC) and post-weaning (PC) conformation, weaning (WP) and post-weaning (PP) precocity, weaning (WM) and post-weaning (PM) muscling and scrotal circumference (SC) were also used. All models included the fixed contemporary group effect and random animal, maternal genetic and permanent environment effects. Each model was tested against all other models for all nine traits using the likelihood ratio test. The complete model, including all additive and non-additive effects and the model without complementarity, were seen to be the best options to analyze this crossbred population. However, least squares may not be the best methodology due to possible collinearity among estimates that may inflate the variance. In the complete model most effects were statistically significant (P<0.01) for weaning traits, except for direct and maternal breed additive effects and direct complementarity effect for WM. For post-weaning traits, the direct complementarity effect for phenotypic scores (PC, PP and PM) and the maternal heterosis effect for PG, PC, PM, were not statistically significant. For scrotal circumference the maternal complementarity, direct and maternal heterosis and maternal epistatic loss effects were not statistically significant. All other effects were statistically significant (P<0.01). For the model without complementarity, the direct breed additive effect for PG and PP was not statistically significant, including the maternal breed additive effect for WC, WD, PP and PM and maternal heterosis, direct and maternal epistatic loss effects for SC. Considering all models, significant direct breed additive effect was mostly positive for weaning traits and was negative for all post-weaning and SC. The significant maternal breed additive and maternal complementarity effects for SC were all negative. The significant direct and maternal epistatic loss effects were negative for all traits and for all models, except for PG in the complete model and for weaning traits in the model including only breed additive and epistatic loss effects. We conclude that the fixed genetic effects are mostly significant, thus it is important to include them in the model when evaluating crossbreed animals and the models including breed additive effects, heterosis and epistatic loss with or without complementarity were the more appropriate.


      PubDate: 2015-05-04T10:18:35Z
       
  • Association of 20 candidate gene markers with milk production and
           composition traits in sires of Reggiana breed, a local dairy cattle
           population
    • Abstract: Publication date: Available online 3 April 2015
      Source:Livestock Science
      Author(s): L. Fontanesi , E. Scotti , A.B. Samorè , A. Bagnato , V. Russo
      Reggiana is a local dairy cattle breed that currently counts about 2000 cows reared mainly in the province of Reggio Emilia (North of Italy). Reggiana cows are less productive than Holstein cows opening questions about the profitability of this breed whose milk is used to produce a niche brand of Parmigiano-Reggiano cheese. For these reasons, protein content and yield of the Reggiana milk are very important traits. With the aim to identify markers that could be useful to describe genetic variability in this breed and eventually to use them in conservation and marker assisted selection programs, we genotyped 22 DNA polymorphisms of 17 candidate genes (ABCG2, CRH, CSN3, CYP11B1, DGAT1, FGF2, GH1, GHR, KIT, LEP, LGB, ORL1, POU1F1, PRLR, SPP1, STAT1 and TG) in 128 Reggiana sires for which semen was available and we analyzed association among 20 polymorphic markers and milk yield, protein yield (PY), fat yield (FY), protein percentage (PP) and fat percentage (FP) estimated breeding values. Five markers, four of which on Bos taurus chromosome (BTA) 14 (DGAT1 p.K232A, CYP11B1 p.A30V, TG g.9509279C>T, CRH p.S45D) and one on BTA19 (GH1 p.L153V), were highly associated (P<0.01) with several production traits (PP, FY and PY; FP; PY; FY; PP and FP; respectively). This study is the largest investigation of molecular markers carried out in this breed so far and represents one of the few attempts to identify DNA markers affecting production traits in a cattle breed constituted by a very small population. Obtained results could open new possibilities for conservation and breeding programs in Reggiana cattle.


      PubDate: 2015-05-04T10:18:35Z
       
  • Survival analysis of genetic and non-genetic factors influencing ewe
           longevity and lamb survival of Ethiopian sheep breeds
    • Abstract: Publication date: Available online 3 April 2015
      Source:Livestock Science
      Author(s): T. Getachew , S. Gizaw , M. Wurzinger , A. Haile , B. Rischkowsky , A.M. Okeyo , J. Sölkner , G. Mészáros
      Survival analysis applying proportional hazards models was used to investigate genetic and non-genetic factors affecting ewe longevity and lamb survival of sheep in Ethiopia. Data were obtained from an on-station closed nucleus breeding program of Menz sheep and an on-farm Awassi×Menz sheep crossbreeding project. A total of 695 ewes and 1890 lambs born from the nucleus population of Menz sheep were used for the analysis of ewe productive life and lamb survival to yearling age respectively. In addition, 5530 lamb records of purebred local and crossbreds with proportions of ~25–50% Awassi, collected from three locations were used for the analysis of lamb survival from birth to weaning age. The effects of year, ewe parity and litter weight at weaning were significant (p<0.05) for ewe productive life. On-station lamb survival to yearling was affected by year and breeding value of yearling weight of the lamb, indicating that faster growing animals had substantially higher survival rates. Animal model heritability estimates for lamb mortality ranged from 0.02 to 0.10. While there was a strong genetic trend for growth rate, as evidenced by estimated breeding values for different birth years, estimated breeding values for lamb survival were variable across years with decreasing trend. These results indicate no antagonism between growth rate and survival under conditions prevailing in the nucleus system. Routine genetic evaluation for survival is suggested. Under farmer conditions, the effects of year, season, sex and location effects were significant (p<0.05) on lamb survival to weaning age whereas breed composition (local versus crossbred) of dam as well as of the lamb were not significant. This seems to indicate that crossbreeding of local animals with Awassi sheep does not have an adverse effect on the survival of lambs under farmer conditions typical for the Ethiopian highland regions included in this study.


      PubDate: 2015-05-04T10:18:35Z
       
  • Does the presence of umbilical outpouchings affect the behaviour of pigs
           during the day of slaughter?
    • Abstract: Publication date: Available online 4 April 2015
      Source:Livestock Science
      Author(s): Sarah-Lina Aa. Schild , Pia Brandt , Tine Rousing , Mette S. Herskin
      The aim of the present study was to examine behavioural and clinical consequences of the presence of umbilical outpouchings (UOs) in pigs during the day of slaughter, in order to establish new knowledge of relevance for the assessment of fitness for transport of these animals. Based on the Danish national guidelines involving the diameter of the UOs, considerable attention was paid to this measure. A total of 29 pairs of pigs from seven different commercial herds with standard pig housing, involving pens of partially slatted flooring, were included in this observational study. Focal animals were selected in the home pen on the day before transport to the abattoir and subjected to a clinical evaluation involving scores of skin lesions in healthy control animals and pigs with UOs. On the day of slaughter, video recordings were conducted during unloading at the abattoir and in the race to the stunner. For both pigs with UOs and control pigs, the skin lesion score increased over the day of slaughter. No significant differences between pigs with UOs and controls were found for any of the measures considered relevant for the fitness for transport.


      PubDate: 2015-05-04T10:18:35Z
       
  • Evaluation of five models predicting feed intake by dairy cows fed total
           mixed rations
    • Abstract: Publication date: Available online 6 April 2015
      Source:Livestock Science
      Author(s): L.M. Jensen , N.I. Nielsen , E. Nadeau , B. Markussen , P. Nørgaard
      The objective of this study was to evaluate the accuracy of five models predicting dry matter intake (DMI) in dairy cows fed total mixed ration (TMR). The five models were the North American model from NRC, and the Northern European models: NorFor (Denmark, Iceland, Norway, and Sweden), TDMI (Finland), Zom (the Netherlands), and Gruber (Austria, Germany, Switzerland). The evaluated models represent different approaches to predict DMI. One approach uses only animal characteristics; a second uses the interaction between animal and dietary characteristics, and a third uses no production characteristics, such as body weight or milk yield. These different modelling approaches results in very different substitution rates, where only two of the models demonstrate direct or indirect relation to concentrate allocation. Accuracy of DMI prediction was evaluated by mean square prediction error (MSPE), root mean square prediction error (RMSPE), together with the decomposition of error into error of central tendency (ECT), error of regression (ER), and error due to disturbance (ED). The evaluation was performed on data from 12 Scandinavian production experiments with a total of 917 lactating dairy cows in 94 treatment means. The NorFor model was evaluated on only 9 of the experiments as 3 experiments had been used in the development of this model. The five models predicted DMI in groups of dairy cows fed TMR with RMSPE ranging between 1.2kg dry matter (DM) per day for the Gruber model to 3.2kg DM per day for the Zom model. Evaluated across the experiment the ECT and the ER ranged between 0.3% and 65% and between 3% and 38% of MSPE, respectively. Error associated to ED ranged between 31% and 93% of MSPE. When all five models were evaluated for prediction of DMI both across and within experiments, results revealed that all five models predicted differences between diets within experiments better than differences across experiments. The Gruber model, which predicted DMI most accurately did so due to its negligible systematic error (ECT, ER) resulting in 93% of the error located in ED.


      PubDate: 2015-05-04T10:18:35Z
       
  • Effect of replacing barley with wheat grain in finishing feedlot diets on
           nutrient digestibility, rumen fermentation, bacterial communities and
           plasma metabolites in beef steers
    • Abstract: Publication date: Available online 6 April 2015
      Source:Livestock Science
      Author(s): M.L. He , J. Long , Y. Wang , G. Penner , T.A. McAllister
      This study investigated the effect of substituting barley grain with wheat on rumen fermentation, bacterial communities, nutrient digestibility and plasma metabolites in finishing feedlots steers. The experiment was designed as a replicated 4×4 Latin square with 8 rumen cannulated steers (742±44kg) fed diets in which wheat was substituted for 0, 30%, 60% or 89% of barley grain dry matter (DM). All grains were dry-rolled to a processing index (PI) of 80% expressed as a percentage of volume weight of processed grain divided by the volume weight of unprocessed grain. The remaining dietary ingredients consisted of 6% barley silage and 5% supplement. Duration of pH below 5.8 linearly increased (P=0.04) with increasing levels of wheat, whereas average, minimum and maximum pH as well as the time and area under pH 5.5 (P=0.08) and 5.2 (P=0.18) did not differ among diets. Likewise, volatile fatty acids (VFA) profiles, concentrations of VFA, ammonia, numbers of protozoa and total tract digestibility of nutrients were unaffected (P>0.05) by this substitution. Increasing levels of wheat linearly increased copy numbers of 16S rRNA for total bacteria (P=0.01) and Ruminococcus amylophilus (P=0.04) per g of rumen contents. Inclusion of wheat in the diet linearly reduced plasma albumin (P=0.03) and urea nitrogen (P=0.01) concentrations, but did not affect (P>0.05) other major plasma metabolites. In conclusion, replacing barley grain with wheat in the diets of feedlot steers had little negative impact on nutrient digestibility or rumen fermentation, however, it increased the daily duration that rumen pH remained below 5.8. These data suggest that there is little difference in the ruminal fermentation or digestibility of barley vs wheat if both grains are processed to a similar degree.


      PubDate: 2015-05-04T10:18:35Z
       
  • The importance of the DMRT3 ‘Gait keeper’ mutation on riding
           traits and gaits in Standardbred and Icelandic horses
    • Abstract: Publication date: Available online 6 April 2015
      Source:Livestock Science
      Author(s): Kim Jäderkvist , Niina Holm , Freyja Imsland , Thorvaldur Árnason , Leif Andersson , Lisa S. Andersson , Gabriella Lindgren
      Previous studies have shown that a single base-pair mutation, a change from cytosine (C) to adenine (A), in the DMRT3 gene affects both the ability to show ambling and lateral gaits in a wide range of horse breeds, as well as racing performance and trotting technique in Standardbred and Nordic trotters. The variant allele is present in gaited breeds but is absent, or found at a very low frequency, in breeds used for Western-European style riding and flat racing, like the Swedish Warmblood and Thoroughbreds as well as in draught horses. This indicates that the variant allele might have a negative effect on certain riding performance traits in horses. Therefore, one aim of this study was to investigate whether the DMRT3 variant affects canter in Standardbred trotters, and to test if heterozygous horses (CA) were better suited for Western-European style riding than homozygous horses (AA). Riding traits were studied in 115 Standardbred horses, and a similar study was also performed with data from 55 Nordic trotters. The results showed that CA Standardbreds had significantly better balance in canter, both collected and extended canter, than AA horses. The CA horses also got significantly higher scores for transitions in collected canter. For the rhythm we found no significant differences between the genotypes. In the Nordic trotters we were unable to establish any significant difference for canter ability. Another aim of this study was to investigate the effect of the variant allele on riding abilities and gaits in the Icelandic horse (n=446). Practically all horse breeds considered to be three-gaited have a CC genotype, in contrast Icelandic CC horses can show tölt. We therefore tested whether the variant influenced how difficult it was to initiate tölt training for these horses. It was also investigated whether the variant affects which gaits Icelandic horses choose, both at liberty and during initial training. Icelandic CC horses were significantly more difficult to train to tölt compared to CA and AA horses. The AA Icelandic horses showed the lateral gaits tölt and pace significantly more frequent, both at liberty and during initial training, than CA or CC horses. The majority of the Icelandic CC and CA horses chose trot at liberty and during initial training.


      PubDate: 2015-05-04T10:18:35Z
       
  • A comparison of two enzymatic in vitro methods to predict in vivo organic
           matter digestibility of perennial ryegrass
    • Abstract: Publication date: Available online 8 April 2015
      Source:Livestock Science
      Author(s): M. Beecher , R. Baumont , J Aufrère , T.M. Boland , M.O’ Donovan , N. Galvin , C. Fleming , E. Lewis
      Accurate grass organic matter digestibility (OMD) values are required for intake prediction, for calculating metabolisable protein and ultimately to accurately formulate diets. The three objectives of this study were: (i) to compare the neutral detergent cellulase (NDC)- and pepsin cellulase (PC)-predicted OMD to in vivo OMD; (ii) to compare the NDC method to the PC method for accurately estimating grazed grass OMD and (iii) to compare the effect of sample preparation on the NDC method results, specifically oven drying samples at 60°C compared to freeze drying at –55°C. Data consisted of 34 forage grass samples on which OMD was measured in vivo using the total faecal collection method in sheep (OMDINVIVO). The grass samples were also analysed in vitro in triplicate. For the NDC method the samples were oven-dried at 60°C for 48h or were freeze-dried at –55°C for 1 week. The PC method samples were oven-dried at 60°C for 72h. The NDC organic matter solubility (OMS) results were inserted into the equation developed by Stakelum et al. (1988) to give OMDNDC. The OMS results from the PC method were inserted into the equation developed by Aufrère et al. (2007) to give OMDPC. The comparison between OMDPC 60 (mean±standard error) (0.708±0.0361; n=34) and OMDINVIVO (0.719±0.0361) showed that there was a tendency for the two methods to give different results (P=0.06). The comparison between OMDNDC FD (0.740±0.0049; n=18) and OMDINVIVO (0.764±0.0063) showed that the two methods gave different results (P<0.01). The comparison between OMDNDC 60 (0.680±0.0265; n=34) and OMDINVIVO (0.719±0.0361) showed that the two methods gave different results (P<0.05). The positive correlation with OMDINVIVO suggested that OMDNDC FD, OMDNDC 60 and OMDPC 60 were able to predict OMDINVIVO of perennial ryegrass grazed swards. The comparison between OMDNDC FD (0.740±0.0049) and OMDPC 60 (0.746±0.0109) showed that the two methods gave similar results (P>0.05). The comparison between OMDNDC 60 (0.680±0.0230) and OMDPC 60 (0.708±0.0230) showed that the two methods tended to give different results (P=0.06). To improve the relationship between OMDINVIVO and OMDNDC FD, and between OMDINVIVO and OMDNDC 60, future work should expand the number of grass samples, the months of the year over which samples are collected and the range of chemical composition and OMDINVIVO of the samples. Sample preparation method had an effect on the NDC-predicted OMD results as OMSNDC FD differed to OMSNDC 60 and OMDNDC FD differed to OMDNDC 60. This indicated that specific correction (regression) equations must be used for specific sample preparation methods.


      PubDate: 2015-05-04T10:18:35Z
       
  • Comparison of fixed effects and mixed model growth functions in modelling
           and predicting live weight in pigs
    • Abstract: Publication date: Available online 9 April 2015
      Source:Livestock Science
      Author(s): J.M. Coyne , D.P. Berry , E.A. Mantysaari , J. Juga , N. McHugh
      The objective of the present study was to compare alternative growth functions fitted to pig live weight data, with particular emphasis on the function's ability to predict future animal live weight. The final dataset consisted of 51,893 live weight records from 10,201 pigs aged between 61 and 200 days. Fixed effects models and mixed models were applied to the three different growth functions: von Bertalanffy, Gompertz, and Richards; fixed and mixed model polynomial equations were also considered. The growth function's ability to predict future live weight was determined by excluding a selection of animal live weight records post 160 days of age and comparing the predicted live weight to actual live weight. Irrespective of whether a fixed or mixed model framework was used, the Gompertz function best modelled the full dataset, with an accuracy squared for the full dataset ( r w 2 ) of 0.997 and root mean square error (RMSE) of 1.60kg for the fixed effects model and r w 2 of 0.995 and RMSE of 2.25kg for the mixed model equation. The Gompertz mixed model also achieved the greatest accuracy squared of predicting ( r w w ˆ 2 ) future live weight records, with an r w w ˆ 2 of 0.846 and RMSE of 5.35kg. A strong positive correlation was estimated between asymptotic mature weight (A; r=0.83 to 0.96) across the three growth functions for all considered equations. A strong negative correlation was estimated between parameters A and k (rate of maturation) for the Gompertz fixed effects model (-0.88) and mixed model (-0.70). Results from this study could be used to implement a decision support tool for pork producers, offering extra information when they are making important feeding, slaughter and breeding decisions.


      PubDate: 2015-05-04T10:18:35Z
       
  • Effects of extracellular polysaccharides of Ganoderma lucidum
           supplementation on the growth performance, blood profile, and meat quality
           in finisher pigs
    • Abstract: Publication date: Available online 9 April 2015
      Source:Livestock Science
      Author(s): X.L. Li , L.P. He , Y. Yang , F.J. Liu , Y. Cao , J.J. Zuo
      The objective of the present study was to evaluate the effect of the addition of extracellular polysaccharides of Ganoderma lucidum (EPG) on growth performance, blood profile, and meat quality of longissimus muscle (LM) in finisher pigs. A total of 60 castrated finisher barrows [(Duroc × Yorkshire) × Landrace] with an average initial body weight (BW) of 54.6 ± 0.6kg were randomly allotted to 1 of 2 treatments (3 pens/treatment and 10 pigs/pen): control (basal diet) and EPG (basal diet + 800mg/kg of EPG). The duration of the experiment was 70 d. Results showed that dietary EPG addition increased serum concentrations of immunoglobulin G (IgG) (P = 0.017), interleukin-2 (IL-2; P = 0.008), and globulin (P = 0.024) and reduced albumin (P = 0.032) and the ratio of albumin to total protein (P = 0.035). Serum concentrations of triglyceride (P = 0.043), total cholesterol (P = 0.023), low-density lipoprotein (LDL) cholesterol (P=0.014), and creatine kinase (P = 0.006) decreased in the EPG treatment group. Dietary supplementation of EPG affected fat traits by increasing marbling score (P = 0.015), the content of total fat (P = 0.045), and the proportion of oleic acid (P = 0.023) in LM. Moreover, inclusion of EPG reduced stearic acid expressed as percentage of total fatty acids (P = 0.018) in LM. Furthermore, the addition of EPG in diets increased the pH of LM of pigs at 45min (P = 0.042) and 24h (P = 0.036) post-mortem, and the redness (P = 0.031) of LM. Increased content of inosine monophosphate acid (IMP) (P = 0.044) and decreased drip loss (P = 0.020) in LM of pigs were also observed in the EPG treatment group. In addition, dietary EPG addition has no adverse effect on the growth performance of finisher pigs. In conclusion, EPG is a potential feed additive for promoting animal health and improving quality of pork.


      PubDate: 2015-05-04T10:18:35Z
       
  • Use of descriptors to define clusters of herds under similar environmental
           conditions to improve the level of connection among contemporary groups of
           mutton type merino sheep under an extensive production system
    • Abstract: Publication date: Available online 9 April 2015
      Source:Livestock Science
      Author(s): J. Osorio-Avalos , A. Menéndez-Buxadera , J.M. Serradilla , A. Molina
      An analysis of the genetic connections among the herds constituting the selection nucleus of the mutton type of Merino sheep in Spain has been carried out in order to improve the reliability of the genetic evaluations. Four climatic variables, registered in weather stations located near the farms, and 16 variables (10 of them related to the production and managing systems and other six related to production traits), registered in 23 farms, were subjected to a discriminant analysis, resulting in seven eigenvectors explaining 78.3% of the variance and four groups (clusters) of farms with similar values for formerly mentioned variables. The relative efficiency of the genetic evaluation models including these clusters of herds in respect to the conventional models including single herd effects was estimated through the analysis of 50,503 weights of lambs at 75 days of age (near weaning) using the method of Criterion of Admission to the Group of Connected Herds (CACO), which compares the average coefficients of determinations (CD) of the herds, which is a measure of the degree of connection among herds through common ancestors. Results obtained showed that the values of the contrasts of the CD of the herds were between 2.3% and 14.9% higher (depending on the heritability of the trait) when the model with the clusters was used. When other heritability estimates of weights at other ages were simulated, the increments of these contrasts ranged between 4.1% and 24.9%. These results suggest defining these new clusters grouping herds with similar climatic, managing and production environments is a good alternative to improve the connections and, consequently, may improve the reliability of the estimates of breeding values when connections among herds are poor due to the absence of artificial insemination.


      PubDate: 2015-05-04T10:18:35Z
       
  • Effect of timing of pasture allocation on production, behavior, rumen
           function, and metabolism of early lactating dairy cows during autumn
    • Abstract: Publication date: Available online 9 April 2015
      Source:Livestock Science
      Author(s): Rubén G. Pulido , Miguel Ruiz-Albarrán , Oscar A. Balocchi , Pamela Nannig , Fernando Wittwer
      The objective of the present study was to evaluate the effect of timing of pasture allocation on performance, feeding behavior, rumen function and plasma and urine metabolites of early-lactation dairy cows in autumn, strip-grazing a perennial ryegrass sward. Forty-two Holstein Friesian cows were randomly allocated to one of the following treatments: Pasture strips allocated daily at either 10:00h (AM-ALL), 16:50h (PM-ALL) or twice a day at 10:00 and 16:50h (AM–PM). Herbage allowance was 21kg DM/cow/day for all treatments. All cows received a daily allocation of concentrate and grass silage, 3.0 and 3.2kg DM per cow, respectively. Herbage chemical composition differed amongst treatments, as dry matter and WSC contents were greater in PM-ALL than in AM-ALL and AM–PM. Milk yield tended to be greater with PM-ALL (P=0.06) compared with AM-ALL and AM–PM. The concentration of protein tended to be greater with AM–PM (P=0.09) compared with PM-ALL and AM-ALL. Protein and urea concentrations in milk did not differ among treatments. Daily grazing, ruminating and idling times were similar among treatments (P>0.05). During the first 2h, cows in AM-ALL grazed 30 and 15min longer than cows in AM–PM and PM-ALL treatments (P<0.05). Herbage disappearance was greater (P=0.003) in PM-ALL compared with AM-ALL and AM–PM. Treatment did not affect rumen fermentation metabolites, except for the concentration of propionic acid, which was 3% lower for cows in AM–PM compared with AM-ALL and PM-ALL cows. Cows in PM-ALL had lower concentration of urea in plasma 0.88 and 0.68mmol/L less compared with cows in AM-ALL and AM–PM (P=0.04). Concentrations of urinary metabolites were not affected by treatment. These results suggest that timing of pasture strip allocation alters nutrients supplied by herbage to cows, but has only a small effect on herbage dry matter intake. Consequently, allocating the daily pasture strips in the afternoon would tend to increase milk production compared with allocations during the morning (~3) and twice a day (4.4%).


      PubDate: 2015-05-04T10:18:35Z
       
  • A multi-compartment model for genomic selection in multi-breed populations
    • Abstract: Publication date: Available online 11 April 2015
      Source:Livestock Science
      Author(s): El Hamidi Hay , Romdhane Rekaya
      Genome wide evaluation methods are often conducted using purebred populations. Estimation and often validation are carried out using primarily select elite animals. This process is successful when estimated SNP effects are used to predict genomic breeding values of animals of similar breed. This approach fails when SNP estimates in one breed are used for genomic prediction in other breeds. In this study, we proposed a multi-compartment model where the effect of an SNP marker could differ between breeds. Two simulation scenarios were carried out using an admixed population of two divergent lines (A and B), first using a low density panel (300 SNPs) and second using a high density panel (60k SNPs). Divergence between the two lines was artificially created by multiplying marker effects in one line by a variable α which was sampled from different uniform or normal distributions. The proposed method was compared to the pooled data approach based on the accuracy of predicting the true breeding values. In the first simulation scenario, the prediction accuracy using the pooled data approach for line A, was 0.40, 0.39 and 0.38 when α was generated from a uniform distribution between [−2, 2], [−4, 4] and [−8, 8] respectively. Using our proposed method, the corresponding accuracies were 0.47, 0.46 and 0.46, respectively. A similar trend was observed for line B with a clear superiority of the multi-compartment model over the pooled data approach with an increase ranging from 17 to 47% and increases as the divergence between lines increases. In the second scenario, when α was sampled from a uniform [−2.2], accuracy for line A (B) was 0.32 (0.30) using pooled data model, and 0.33 (0.32) using the multi-compartment model. Although smaller than in first simulation scenario, the proposed method still has a superiority of 3 to 7%. Similar performance was observed when α was sampled from uniform [−4,4].


      PubDate: 2015-05-04T10:18:35Z
       
  • Genotype×environment interaction for weaning weight in Nellore cattle
           using reaction norm analysis
    • Abstract: Publication date: Available online 13 April 2015
      Source:Livestock Science
      Author(s): S. Ribeiro , J.P. Eler , V.B. Pedrosa , G.J.M. Rosa , J.B.S. Ferraz , J.C.C. Balieiro
      This study aimed to evaluate the existence of genotype×environment interaction (G×E) for weaning weight in Nellore cattle, using reaction norms. Thus, 58,032 records of weaning weight adjusted to 205 days (WW) were analyzed, from animals born between 1987 and 2005, originating from three herds in different regions of Brazil. A random regression model was used to describe changes in breeding values according to the environmental gradient formed by different contemporary groups. Analyses were carried out utilizing INTERGEN software under a Bayesian approach. The solutions of contemporary groups distributed in the environmental gradient varied from −58 to +56kg, and estimates of direct heritability coefficients ranged from 0.05 to 0.44 through the environmental gradient. Genetic correlation between intercept and slope of the reaction norms was 0.75, and the correlation between breeding values of bulls in different environments ranged from −0.38 to 0.99, being higher in highly favorable environments. The results showed the effect of genotype×environment interaction on weaning weight in the herds of this study, especially on the bulls’ rankings. Thus, the authors emphasize the importance of considering the G×E in the genetic evaluation of Nellore cattle, which will result in increased selection efficiency in the weaning period.


      PubDate: 2015-05-04T10:18:35Z
       
  • Effects of heat stress on semen characteristics of Holstein bulls
           estimated on a continuous phenotypic and genetic scale
    • Abstract: Publication date: Available online 14 April 2015
      Source:Livestock Science
      Author(s): A. Al-Kanaan , S. König , K. Brügemann
      Semen volume (SV), semen output (SO), semen motility (SM), number of semen doses per ejaculate (NSD) and semen concentration (SC) were analyzed on a phenotypic and quantitative genetic scale in dependency of the continuous environmental descriptor THI (=an index describing combinations of temperature with humidity). Longitudinal semen data included 10,341 observations from 562 Holstein sires kept on an AI station in the northwestern part of Germany. Statistical modeling was based on fixed and random regression methodology (RRM). In this context, the phenotypic and genetic trajectory of traits in dependency of THI was modeled by orthogonal polynomials, i.e. Legendre polynomials of order 3. A general heat stress threshold of THI=60 was identified, and indicating detrimental effects of heat stress beyond this threshold, especially on SV, SO, NSD, and SC. Least square means for semen productivity were generally higher for adult bulls, but compared to young bulls, adult bulls responded with stronger semen production losses for extremely high THI. The optimal environment for semen production was a THI in the range from 50 to 60. Detrimental impact of heat stress was reduced for bulls with longer intervals between consecutive semen collection dates. Heritabilities for semen traits were in a low to moderate range with the following maximal values: 0.18 for SV at THI 30, 0.29 for SM at THI 70, 0.26 for SO at THI 30, 0.26 for NSD at THI 58, and 0.27 for SC at THI 53. Genetic values of sires and additive genetic variances changed with alterations of THI, with highest genetic variances at the extreme ends of the continuous environmental descriptor. Genetic correlations in same traits from THI levels in great distance were lower than 0.80, and indicated genotype by environment interactions. Application of RRM allow to select sires according to THI specific breeding values, which implies an optimization of cow sire and bull sire selection for harsh environments.


      PubDate: 2015-05-04T10:18:35Z
       
  • Comparing multi-trait Poisson and Gaussian Bayesian models for genetic
           evaluation of litter traits in pigs
    • Abstract: Publication date: Available online 18 April 2015
      Source:Livestock Science
      Author(s): Henrique Torres Ventura , Fabyano Fonseca e Silva , Luiz Varona , Elsio Antônio Pereira de Figueiredo , Edson Vinícius Costa , Luciano Pinheiro da Silva , Ricardo Ventura , Paulo Sávio Lopes
      Reproductive traits as number of piglets born (NPB) and weaned (NWP) are directly related to the economic efficiency of swine production systems. Pig breeding programs seek to increase the number of weaned piglets per sow per year, and the NPB is among the factors that directly and indirectly influence the NWP. Thus, multi-trait evaluations are essential to estimate heritabilities and mainly genetic correlations between these traits over different farrowing orders. In general, Gaussian linear mixed models have been used to genetic evaluation of litter traits; however since these traits are characterized as count variables, Poisson models are also indicated. Some studies were carried out using Poisson mixed models in the area of Animal Breeding and Genetics, but they do not point out for a multi-trait scenario, as it should be for litter size at birth and weaning. Toward this orientation, we aimed to apply a multi-trait Poisson mixed model (MPM) for the genetic evaluation of the number of born and weaned piglets under a Bayesian framework. It was aimed also to compare the proposed model with the traditional multi-trait Gaussian model (MGM) by using posterior based goodness-of-fit measures. Two-trait analyses for NPB and NWP were performed separately by each considered farrowing order (first, second and third) using MPM and MGM fitted to data from a commercial Landrace population. Based on DIC (Deviance Information Criterion) and PMP (Posterior Model Probability) values, the MGM outperformed the MPM, but the genetic parameter and breeding values provided by both models were consistent and similar over the three first farrowing orders. Bayesian generalized a multi-trait mixed model approach is feasible for genetic evaluations in the animal breeding context and can be an alternative method for genetic evaluations assuming non-Normal phenotypes.


      PubDate: 2015-05-04T10:18:35Z
       
  • Energy requirements for maintenance and growth of early-weaned Dorper
           crossbred male lambs
    • Abstract: Publication date: Available online 21 April 2015
      Source:Livestock Science
      Author(s): G.-S. Xu , T. Ma , S.-K. Ji , K.-D. Deng , Y. Tu , C.-G. Jiang , Q.-Y. Diao
      This study aimed to investigate the net and metabolizable energy (NE and ME) requirements of Dorper crossbred lambs. Thirty-five Dorper×thin-tailed Han crossbred intact male lambs weaned at approximately 50d of age (20.26±1.29kg of BW), were used. Seven randomly selected lambs were slaughtered at the start of the trial (baseline group). An intermediate group consisting of 7 randomly selected lambs fed for ad libitum intake was slaughtered when the lambs reached an average BW of 28.2kg. The remaining 21 lambs were alloted randomly to 3 levels of dry matter intake: ad libitum, or restricted to 70 or 40% of the ad libitum intake. All the lambs were slaughtered when the ad libitum fed sheep reached 35kg of BW. Total body energy, crude protein, fat, ash, and moisture contents were determined. In a digestibility trial, fifteen Dorper×thin-tailed Han crossbred intact male lambs (32.38±2.23kg of BW) were housed in metabolism cages and used in a completely randomized design experiment to evaluate the ME value of the diet at 3 feed intake levels. The results showed that the maintenance requirements for NE and ME were 250.61 and 374.21kJ/kg metabolic shrunk body weight (SBW0.75), respectively. The partial efficiency of energy use for maintenance was 0.67. Net energy requirements for growth ranged from 1.12 to 5.31MJ/d, for the lambs gaining 100 to 350g/d from 20 to 35kg BW. Partial efficiency of ME for growth was 0.42. In conclusion, the current study suggested that the NE requirement for maintenance and growth of Dorper×thin-tailed Han early-weaned crossbred lambs were lower than those reported by existing AFRC and NRC nutritional systems.


      PubDate: 2015-05-04T10:18:35Z
       
  • Planimetric measurement of floor space covered by fattening rabbits and
           breeding does in different body positions and weight classes
    • Abstract: Publication date: Available online 21 April 2015
      Source:Livestock Science
      Author(s): Mona Franziska Giersberg , Nicole Kemper , Michaela Fels
      The aim of this study was to measure the exact floor space that a rabbit occupies due to its physical size and shape. For this purpose the colour contrast planimetric method “KobaPlan” was used which had originally been developed to calculate the surface of chicken. A total of 704 images of fattening rabbits and breeding does were taken from a top view. The rabbits were weighed individually, and photographed digitally in a special planimetric box. In the photo, the number of animal associated pixels was counted by the “KobaPlan” software, and thus the area covered by the animal was calculated. The calculated surfaces of the rabbits were assigned to weight classes which covered a range from 1.0 to 5.5kg. We defined four body postures of rabbits, one sitting position and three different recumbent positions. The mean floor space covered by sitting rabbits at the beginning of the fattening period was 246±34cm², whereas recumbent rabbits covered 294±45cm², 360±51cm² and 338±39cm² in different positions. At the time of slaughter, the covered floor spaces increased to 509±23cm² for sitting rabbits, and to 697±45cm², 724±26cm² and 719±23cm² for recumbent rabbits, respectively. The calculated surface of breeding does with a body weight of 4.5kg was 657±17cm² in sitting position, and 828±7cm², 874±23cm² and 882±14cm² in the different recumbent positions. The heaviest does (5.5kg) covered 739cm² sitting and 1026±27cm² recumbent. There was a linear increase in the surface covered by rabbits in all defined body positions as a function of live weight. Furthermore, sitting rabbits covered significantly less floor space than lying rabbits (P<0.05). It was shown that the colour contrast planimetric method “KobaPlan” provides reliable results regarding the floor space covered by growing rabbits and breeding does. This study is a first step towards an optimization of current rabbit housing regarding individual space requirement, and it represents a useful basis for planning new environmental enrichment structures (e.g. withdrawal areas) in rabbitries.


      PubDate: 2015-05-04T10:18:35Z
       
  • Influence of ruminal quebracho tannin extract infusion on apparent
           nutrient digestibility, nitrogen balance, and urinary purine derivatives
           excretion in heifers
    • Abstract: Publication date: Available online 21 April 2015
      Source:Livestock Science
      Author(s): S. Ahnert , U. Dickhoefer , F. Schulz , A. Susenbeth
      Six fully grown heifers (491kg body weight, standard deviation 35) fitted with ruminal cannulae received incremental dosages of a commercial Quebracho tannin extract (QTE) to investigate its effects on apparent total tract nutrient digestibilities, nitrogen balance, and purine derivatives excretion as an indicator of duodenal microbial crude protein flow. The basal diet comprised 2.6kg/d grass hay, 2.6kg/d concentrate feed, and 60g/d of a mineral premix (as-fed basis) and was offered in two equal meals. The QTE was administered at 0 (CON 1), 1, 2, 4, or 6% of the daily DM intake from the basal diet (i.e., 45 g, 90 g, 180 g, and 270 g/d; as-fed basis). For this, half of the daily QTE dosage was suspended in water and intraruminally infused during each feeding. All animals simultaneously received the same QTE dosage. Every period comprised 9 d of adaptation and 6 d of total urine and feces collection. Subsequent to highest QTE dosage, infusion was ceased and after 14 d of adaptation, urine and feces were collected again for 10 d (CON 2). The QTE infusions at≥4% lowered apparent total tract organic matter digestibility (P≤0.045). The effects were more pronounced for neutral detergent and acid detergent fiber digestibilities which decreased from 0.718 and 0.626 without QTE to 0.590 and 0.493 at 6% QTE, respectively (P<0.001). Nitrogen excretion linearly decreased in urine (P=0.003) and linearly increased in feces (P<0.001) with incremental QTE dosages. Irrespective of the dosage level, nitrogen retention was higher with than without QTE infusion (P≤0.035). Urinary purine derivatives excretion declined from 103mmol/d at 1% QTE to 80mmol/d at 6% QTE (P<0.001), indicating a 36% decrease in estimated duodenal microbial crude protein flow. At QTE dosages of≥4% of DM intake, reduced carbohydrate digestibility will lower energy supply to the host animal. The pronounced decrease in estimated microbial protein synthesis even at moderate QTE levels is unlikely to be compensated by the increase in rumen-escape protein. The QTE addition to ruminant diets might not improve protein supply and performance of cattle.


      PubDate: 2015-05-04T10:18:35Z
       
  • Conjugated linoleic acid supplementation during late gestation and
           lactation of sows affects myofiber type in their litters
    • Abstract: Publication date: Available online 21 April 2015
      Source:Livestock Science
      Author(s): Renli Qi , Ying Chen , Han Peng , Shan Jiang , Rong Xiao , Jinxiu Huang
      The purpose of this study is to determine the effect of dietary conjugated linoleic acid (CLA) supplementation of pregnant and lactating sows on muscle growth and myofiber type of their piglets. There are thirty healthy, pregnant Rongchang sows with similar body condition and closed expected day of parturition for the experiment in vivo. Three experiment groups carry out with/without CLA (1%, 2% and 0). The experiment began on 85th day of gestation and ended at 28th day after piglet birth. The results show that 1, piglets from CLA-fed sows had heavier longissimus dorsi and higher percentages of slow myofibers than control piglets (P<0.05). 2, moreover, real-time PCR showed that CLA supplementation induce increasing expression of MyHC 1, MyOG, and MyOD genes while decreasing expression of MyHC 2a, MyHC 2x, and MSTN genes in piglets. We also check the expression of genes which appear in 2 in vitro experiment. c9, t11-CLA acted to induce the differentiation of cultured pig skeletal muscle cells and up-regulates the expression levels of MyHC 1 and MyOG, but t10, c12-CLA strongly inhibited cellular differentiation and down-regulates expression of MyOG. These findings suggest that dietary CLA during early life may affect muscle development and myofiber type in pigs.


      PubDate: 2015-05-04T10:18:35Z
       
  • SIALIC ACID CONTENT OF GOAT MILK DURING LACTATION
    • Abstract: Publication date: Available online 22 April 2015
      Source:Livestock Science
      Author(s): Yasmim Regis Formiga de Sousa , Margarida Angélica de Vasconcelos Silva , Roberto Germano Costa , Clayton Anderson de Azevedo Filho , Emmanuela Prado de Paiva , Rita de Cássia Ramos do Egypto Queiroga
      Sialic acid, which is strategically linked to the surface of glycoproteins, glycolipids and free oligosaccharides, is involved in cellular interaction and communication processes. These processes are related to the main biological functions of sialic acid, which include immune system activation, brain development and protection against pathogens. The present study identified and quantified the classes of sialic acid (Neu5Ac and Neu5Gc) in goat milk during lactation. Forty-eight goat milk samples from twelve Saanen goats in four lactation stages were evaluated. Quantification, separation and identification of the compounds were performed using chromatographic method. The goat milk contained high concentrations of sialic acids NeuGc and NeuAc, which then declined at the end of lactation. NeuGc had higher concentrations compared to NeuAc in all the lactation phases. Considering these aspects, the presence of these elements in goat milk provides a potential source of bioactive compounds that can be used as functional ingredient in foods.


      PubDate: 2015-05-04T10:18:35Z
       
  • Evaluating complementary effects of ethanol extract of propolis with the
           probiotic on growth performance, immune response and serum metabolites in
           male broiler chickens
    • Abstract: Publication date: Available online 23 April 2015
      Source:Livestock Science
      Author(s): A. Daneshmand , G.H. Sadeghi , A. Karimi , A. Vaziry , S.A. Ibrahim
      The aim of this study was to evaluate the effects of propolis (a natural resinous substance that bees collect from different sources of plants) extract alone or in combination with probiotics on the growth performance and immune response of male broiler chickens. A total of 256 broiler chickens were randomly assigned to 4 treatments: maize-soybean meal basal diet with no supplement as control, the basal diet containing propolis (0.20g/kg), probiotic (0.45g/kg), or a combination of propolis (0.20g/kg) and probiotic (0.45g/kg). Each treatment consisted of 4 replicated pens with 16 broiler chickens per pen. Broiler chickens had ad libitum access to feed and water and the light program was 23h light/1h dark. The inclusion of propolis extract decreased (P<0.05) body weight and feed intake. Propolis extract alone or in combination with probiotic increased (P<0.05) the relative spleen weight in broiler chickens at 42 d of age compared to the control and probiotic. The relative weight of bursa of Fabricius was greater (P<0.05) in broiler chickens receiving probiotics, propolis extract, or their combination compared to those fed the control diet. Supplementation of diet with probiotic, propolis extract, or a combination of both caused an increase (P<0.05) in the concentration of antibody titer to Newcastle Disease virus. In conclusion, supplementation of the diet with propolis extract decreased the body weight of broiler chickens, however, inclusion of propolis, probiotic, and their combination in the diet caused an immunomodulatory effect in broiler chickens.


      PubDate: 2015-05-04T10:18:35Z
       
  • Effects of diets with High and low protein contents and two concentrate
           levels in Santa Ines x Texel lambs
    • Abstract: Publication date: Available online 23 April 2015
      Source:Livestock Science
      Author(s): R.S. Santos , K.G. Ribeiro , S.C.Valadares Filho , O.G. Pereira , S.D.J. Villela , L.N. Rennó , J.L. Silva
      Two experiments were conducted to evaluate the effects of diets containing two levels of crude protein (CP) and concentrates on the intake, total nutrient digestibility, nitrogen balance (NB), microbial efficiency, and performance of lambs. The diets consisted of 10% or 14.25% CP and 40% or 60% concentrate, with corn silage as the forage. In the digestibility assay, four intact male F1 Santa Ines x Texel lambs, with an average body weight of 21.0±2.48kg and rumen-cannulated, were used. The lambs were distributed in a 4 × 4 Latin square design with four treatments and four periods. There was no effect of the CP x concentrate interaction on the variables that were studied. There was an effect of CP levels on the intake and digestibility of CP, as well as on the amounts of N that were ingested, absorbed, and retained from urine (NB). There was also an effect of CP levels on uric acid excretion. In the performance assay, 32 intact F1 Santa Ines x Texel lambs with an average body weight of 19.0±2.02kg were used. They were distributed in a 2 × 2 factorial arrangement of treatments in a randomized block design with eight replicates. There was a significant interaction between CP and concentrate levels on the ether extract (EE) intake. The CP level affected the intake of dry matter (DM), organic matter (OM), CP, neutral detergent fiber corrected for ash and protein (apNDF), non-fiber carbohydrates (NFC), total digestible nutrients (TDN), and rumen-degraded protein (RDP), as well as the carcass gain (CG) and the feed conversion (FC). Concentrate levels affected the intake of DM, OM, CP, NFC, TDN, and RDP, as well as the CG, the CG/average daily gain (ADG), and the FC. It was concluded that levels of CP and concentrate do not affect microbial efficiency or nutrient digestibility, except for CP digestibility. A high level of CP or concentrate in the diet results in greater nutrient intake and better animal performance.


      PubDate: 2015-05-04T10:18:35Z
       
  • Investigations into genetic variability in Holstein horse breed using
           pedigree data
    • Abstract: Publication date: Available online 23 April 2015
      Source:Livestock Science
      Author(s): L. Roos , D. Hinrichs , T. Nissen , J. Krieter
      A pedigree data set including 129,923 Holstein warmblood horses was analyzed to determine genetic variability, coefficients of inbreeding, the age of inbreeding and the genetic contributions of founder animals and foreign breeds. The reference population contained all horses which had been born between 1990 and 2010. The average Pedigree Completeness Index (PEC) for the reference population was determined as 0.88 and the average complete generation equivalent (GE) was computed at 5.62. The mean coefficient of inbreeding for the reference population (inbred and non-inbred horses) was 2.27%. Most of the inbreeding was defined as “new” inbreeding, which had evolved during recent generations. The effective population size and the effective number of founders were calculated to be 55.31 and 50.2 effective individuals respectively. The most influential foreign breed was the English Thoroughbred with a contribution of 25.98%, followed by Anglo Normans (16.38%) and Anglo Arabians (3.27%). At 2.75%, Hanoverian warmblood horses were determined to be the most important German horse breed. The stallions Cor de la bryere, Ladykiller xx and Cottage son xx were found to be the most important male ancestors. The mare Warthburg was defined as the most affecting female. It was possible to detect the occurrence of the loss of genetic diversity within the Holstein horse breed, related to unequal founder contributions caused by the intensive use of particular sire lines. However, a slight increase in the effective population size and a stagnation of inbreeding during the last generation might show the impact of more open access given to foreign stallions in the recent past.


      PubDate: 2015-05-04T10:18:35Z
       
  • Response of pigs divergently selected for residual feed intake to
           experimental infection with the PRRS virus
    • Abstract: Publication date: Available online 27 April 2015
      Source:Livestock Science
      Author(s): J.R. Dunkelberger , N.J. Boddicker , N.V.L. Serão , J.M. Young , R.R.R. Rowland , J.C.M. Dekkers
      Feed efficiency is of great importance to the swine industry, yet few studies have evaluated the robustness of pigs selected for increased feed efficiency based on residual feed intake (RFI) when challenged with disease. RFI is calculated as the difference between the observed and expected feed intake. The objective of this study was to assess the effect of porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV) infection on lines of pigs divergently selected for RFI. Hypothesizing that the more feed efficient low RFI (LRFI) pigs would be more affected by PRRSV-infection, 97 piglets from LRFI and 99 piglets from high RFI (HRFI) selection lines were experimentally infected with the NVSL 97–7985 PRRSV isolate 1 to 3 weeks post-weaning. Pig body weight was recorded weekly and used to calculate average daily gain (ADG). For comparison, ADG was also evaluated on 489 non-challenged LRFI and HRFI pigs housed in a separate facility. Viral load (VL) was quantified as area under the curve for 0–21 days post-infection (dpi) of the log of PCR-based serum viremia. Antibody level was analyzed from serum samples collected at 4, 7, and 11 dpi by PRRS ELISA and MAGPIX assays to quantify PRRSV-specific IgG antibody and total antibody, respectively, during the early stages of PRRSV-infection. There was a tendency for pigs from the LRFI line to have lower VL (P=0.09), greater ADG (P=0.10), and be more likely to survive the PRRSV-challenge (P=0.06) than pigs from the HRFI line. However, joint analysis of challenged and non-challenged pigs showed a significant interaction between RFI line and challenge status (P=0.04), which demonstrated that growth of the LRFI line was less affected by PRRSV-challenge than growth of the HRFI line. Additionally, a significant interaction between RFI line and dpi for the ELISA (P<0.001) and MAGPIX (P=0.007) assays indicated that the increase in antibody levels from 7 to 11 dpi was greater for the LRFI line than for the HRFI line. In conclusion, the line selected for increased feed efficiency based on RFI (LRFI line) had greater growth under challenge and was therefore less affected by the PRRSV-challenge than the line selected for reduced efficiency (HRFI line). This suggests that the pigs selected for reduced RFI were more robust to the viral challenge.


      PubDate: 2015-05-04T10:18:35Z
       
  • Effect of mycobacterium avium subsp. paratuberculosis infection status on
           culling and calving difficulty in dairy cattle
    • Abstract: Publication date: Available online 28 April 2015
      Source:Livestock Science
      Author(s): I. Mato , N. Pesqueira , C. Factor , M.L. Sanjuan , E. Yus , R. Fouz , I. Arnaiz , F. Camino , F.J. Diéguez
      The present paper was designed to assess the effect of Mycobacterium avium subsp. paratuberculosis (MAP) infection status (antibody positive vs antibody negative, as measured by ELISA) on time to culling and calving difficulty in dairy cows. The study was carried out in 8 dairy farms in Galicia (north-west Spain). All of them were taking part in an ongoing paratuberculosis control program, as well as in a dairy herd improvement program. In order to estimate the relation between time to culling and MAP serological status of dairy cows, the present study followed the Andersen-Gill model for survival analysis. Similarly, in order to evaluate the influence on calving difficulty an ordinal logistic regression model was applied. The results indicated that seropositive cows were more likely to be culled due to death/urgent slaughter (hazard ratio=1.88), low productivity (hazard ratio=2.55), infertility (hazard ratio=4.64) and other causes (hazard ratio=1.67). Additionally, the probability of difficulties at calving time was 2.74 times higher for seropositive cows. The estimated effects could determine the economic benefits of a paratuberculosis control program.


      PubDate: 2015-05-04T10:18:35Z
       
  • The effect of selected staining techniques on stallion sperm morphometry
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): Dorota Banaszewska , Katarzyna Andraszek , Ewa Zdrowowicz , Agata Danielewicz
      A problem in evaluating the morphology and morphometry of sperm is the lack of standardization of staining techniques. The method of staining and evaluating specimens can significantly affect the results of morphometric measurements. The aim of the study was to determine the effect of two techniques for staining stallion sperm on the morphology and morphometric dimensions of sperm cells and the formation of artefacts. The subject of the study was the sperm of Polish Half Bred stallions, isolated post mortem from the tail of the epididymis. Morphometric measurements were made of the following: length, width, perimeter and surface area of the sperm head, surface area of the acrosome, midpiece length, tail length and total sperm length. Sperm evaluation was expanded to include acrosome coverage, i.e. the surface area of the acrosome as a percentage of the total area of the sperm head, and a characterization of the tail, particularly the midpiece. Tygerberg strict criteria were used to evaluate sperm morphology. The data show that the staining method and the chemical reagents applied have a substantial effect on the dimensions and shape of the stallion sperm. The literature on the subject draws attention to the fact that a staining technique should be established or developed which would enable precise and unambiguous analysis of the morphology and morphometry of human and animal spermatozoa. Moreover, a standard should be developed for preparing specimens for morphological analysis. This would enable comparison of results between laboratories, thus enhancing the value of morphological analyses of sperm in predicting and evaluating fertility.


      PubDate: 2015-05-04T10:18:35Z
       
  • Changes of muscle fibre profile and fat cell size around first parturition
           in cows differing in lactation performance
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): Mohamed Hamada , Elke Albrecht , Abdel-Rahman El Bagory , Abo-Bakr Edris , Harald M. Hammon , Gerd Nuernberg , Steffen Maak
      The presented study investigated changes of fat cell and muscle fibre size, and muscle fibre type composition around first parturition in cows with a combined beef and dairy genetic background. In contrast to high-merit dairy cows, these cows can serve as a model for beef cows because of the very low milk production level. Fifty heifers used in this experiment were F 2 offspring originating from mating Charolais bulls to German Holstein cows and a following intercross of F 1 individuals. They were assigned to 3 groups according to their lactation performance, namely high lactating (HL), low lactating long (LLL; duration of first lactation at least 100 days), and low lactation short (LLS; duration of first lactation shorter than 100 days). Biopsy samples were taken from semitendinosus muscle (MST) and subcutaneous fat (SCF) at three time points, 10 days before first parturition, 30 and 100 days after calving. These samples were investigated by histology and computer image analysis for muscle fibre profile, as well as intramuscular and subcutaneous fat cell size to estimate the impact of lactation on body reserves. Most cows continued growth and gained weight during lactation. Continuous tissue accretion was indicated on the cellular level by an increase in intramuscular fat cell size. Subcutaneous fat cells were larger in low lactating cows with a short lactation period. There were no morphological signs of fat mobilization from fat cells. There was also no protein mobilization indicated by changes in muscle fibre size. However, the increase in percentage of fast, glycolytic muscle fibres indicated alterations in muscle metabolism during transition from late pregnancy to early lactation. Cows remained obviously in a positive energy balance in this study and continued tissue accretion during lactation. This was reflected on the cellular level in skeletal muscle and subcutaneous fat.


      PubDate: 2015-05-04T10:18:35Z
       
  • Impact of diet deprivation and subsequent over-allowance of gestating sows
           on mammary gland and skeletal muscle development of their offspring at
           puberty
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): C. Farmer , M.-F. Palin , D. Lösel , C. Rehfeldt , C. Kalbe
      The impacts of diet deprivation and subsequent over-allowance during gestation on mammary development, skeletal muscle histochemistry and gene expression in mammary and muscle tissue of offspring at puberty were determined. Twenty three pubertal gilts (11 control, CTL, and 12 treated, TRT) were used. These gilts were born from sows that were reared under a conventional or an experimental dietary regimen during gestation. The experimental regimen provided 70% (restriction diet, RES) and 115% (over-allowance diet, OVER) of the protein and digestible energy contents provided by the conventional diet. The RES diet was given during the first 10 weeks of gestation followed by the OVER diet until farrowing. Female offspring from these dams were grown until puberty using standard commercial practices and were slaughtered at 212±4 days of age. Mammary tissue and the semitendinosus (ST) muscle were collected. Weights of TRT gilts was less than those from CTL gilts at birth (P<0.05) but were similar thereafter (until puberty, P>0.1). Mammary composition and mammary expression for the genes IGF1, IGF2, ODC1, PRLR-LF, STAT5A, and STAT5B were not affected by treatment (P>0.1). Maternal dietary regime during gestation did not influence skeletal muscle microstructure or relative mRNA abundance for IGF1 and IGF2 (P>0.1). In conclusion, restricted feeding followed by overfeeding of gestating sows has no harmful effects on the development of skeletal muscle and mammary tissue of their female offspring up to puberty.


      PubDate: 2015-05-04T10:18:35Z
       
  • Improved pasture and herd management to reduce greenhouse gas emissions
           from a Brazilian beef production system
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): A.M. Mazzetto , B.J. Feigl , R.L.M. Schils , C.E.P. Cerri , C.C. Cerri
      Brazilian farms produce 15% of the world׳s beef, and consequently they are important sources of greenhouse gases (GHG). The beef sector faces the challenge to meet the increasing demand without further increase of GHG emissions. To reduce the pressure on forests it is essential that farmers are provided with sustainable options of intensification of pasture growth and cattle production. The improvement of the whole-farm beef production system is essential to reduce emissions from all relevant sources, like land use, land use change and livestock. The main objective was to quantify the GHG gas emissions of different beef production systems in Brazil. Therefore we developed a whole farm model that allowed us to calculate GHG emissions from all-important sources (only “on-farm” i.e., not considering emissions from the production of fertilizer, lime or other inputs) for a beef production system in Brazil. We studied the effects of intensification in several steps, starting with a baseline extensive system, followed by four steps of intensification. The main differences between the scenarios are related to pasture management, i.e. continuous or rotational grazing, pasture condition, stocking rate, use of lime and fertilizer, and irrigation; and animal performance, i.e. calving interval, age at first calving, conception rate, total life time until slaughter, and genetic improvement. Compared to the baseline extensive scenario, the total pasture area decreased up to 92% in the most intensified system, while beef production nearly doubled. Intensification increased the number of calves, steers and heifers decreased the total production cycle time and the slaughter age of the steers. Overall, the emission of kgCO2eqkgcarcass−1 was lower with increasing intensification, with an average of 41kgCO2eqkgcarcass−1. The emissions of CH4 decreased, while the emissions of N2O and CO2 increased due to nitrogen fertilizer and lime application. The intensification of beef production, through improved pasture and herd management, reduced the GHG emissions per kg of beef from 2% to 57%. The complete cycle of beef production in intensified systems required less time (years) and area (ha), and may thus help to alleviate the pressure on forests.


      PubDate: 2015-05-04T10:18:35Z
       
  • Fat coating of Ca butyrate results in extended butyrate release in the
           gastrointestinal tract of broilers
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): J.J.G.C. van den Borne , M.J.W. Heetkamp , J. Buyse , T.A. Niewold
      Based on its described beneficial effects on small and large intestinal epithelium, butyrate can be a very good alternative to antimicrobial growth promoters. Effective dietary application requires coating because the majority of uncoated butyrate is purportedly absorbed before reaching the proximal small intestine. Several studies using different protocols reported varying stomach passage times in chickens. In the present study, we compared feeding uncoated vs. fat coated [1-13C] labeled Ca butyrate, and compared the effect of butyrate coating with [1-13C] labeled octanoic acid which is an established indicator of stomach passage. By monitoring 13CO2 expiration continuously, we show that the majority (about 80%) of uncoated Ca butyrate is oxidized proximally of the small intestine, and that base line levels were reached after 6h. Fat coating of Ca butyrate resulted in reduced proximal oxidation (from about 80% to about 45%), and in an extended release pattern of 13CO2 from butyrate similar to that of octanoic acid, and that the return to base line levels was extended to 12h. This indicated that fat coating of butyrate results in absorption along the entire intestinal tract in broilers, offering an explanation for the described beneficial effects as a growth promoter.


      PubDate: 2015-05-04T10:18:35Z
       
  • Optimum standardized ileal digestible tryptophan to lysine ratio for pigs
           weighing 7–14kg
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): J.V. Nørgaard , T.F. Pedersen , E.A. Soumeh , K. Blaabjerg , N. Canibe , B.B. Jensen , H.D. Poulsen
      The objective of the present study was to evaluate the optimum ratio of standardized ileal digestible (SID) Trp to Lys for pigs after weaning. A total of 96 female pigs were allocated to 1 of 6 diets containing 0.13, 0.15, 0.17, 0.19, 0.21, and 0.23 SID Trp:Lys, with 16 individually housed pigs/treatment. The diets contained similar crude protein (154g/kg), NE (10.5MJ/kg), and SID Lys (10.9g/kg). Average daily feed intake (ADFI), average daily gain (ADG), and gain to feed ratio (G:F) were determined for a 21-d period. Blood and urine samples were collected on d 8 and 15. Urea concentration in plasma and urine decreased (P<0.001) concurrently with increasing SID Trp:Lys. The ADFI, ADG, and G:F improved (P<0.001) with increasing SID Trp:Lys. By fitting by a curvilinear-plateau model, minimum SID Trp:Lys to support optimum ADFI, ADG, and G:F were estimated to be 0.20, 0.20, and 0.16, respectively. By fitting a broken-line model, the minimum SID Trp:Lys was estimated to be 0.18, 0.18, and 0.15 for optimum ADFI, ADG, and G:F, respectively. In conclusion, growth performance of pigs weighing 7–14kg increased up to 0.20 SID Trp:Lys.


      PubDate: 2015-05-04T10:18:35Z
       
  • Oregano, rosemary and vitamin E dietary supplementation in growing
           rabbits: Effect on growth performance, carcass traits, bone development
           and meat chemical composition
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): R. Cardinali , M. Cullere , A. Dal Bosco , C. Mugnai , S. Ruggeri , S. Mattioli , C. Castellini , M. Trabalza Marinucci , A. Dalle Zotte
      The study aimed to evaluate the effect of dietary supplementation with different natural additives (aqueous extracts) on the performance of growing rabbits, the nutritional composition and oxidative stability of their meat and on their hind leg bone traits. For this experiment, 200 New Zealand White rabbits weaned at 30 days of age were randomly allocated into five dietary groups (n=40 rabbits/group) until 80 days of age, when they were sacrificed. Dietary groups were: S (standard diet with no supplementation), E (standard diet+150ppm vitamin E positive control), O (standard diet+0.2% oregano, Origanum vulgare, aqueous extract), R (standard diet+0.2% rosemary, Rosmarinus officinalis, aqueous extract) and OR (standard diet+0.1% oregano extract+0.1% rosemary extract). An additional 50ppm vitamin E was added to each diet. Rabbits in the O and OR groups showed the highest final live weight and carcass weight (P<0.001). Oregano supplemented animals also had the best feed conversion ratio. Longissimus dorsi (LD) meat of E and R rabbits had higher protein content compared to O and OR (P<0.001) which had a higher moisture content than E rabbits (P<0.005). All dietary treatments improved the oxidative stability of the LD meat compared to the S group. Treatments O and E were the most effective in delaying the lipid oxidation of LD meat, followed by the OR and R diets (P<0.005). No significant differences among groups in composition of the hind leg meat (HL) were observed. The O rabbits had a higher bone weight (P<0.05) than E animals and this difference was mainly ascribable to femur weight (P<0.01). In conclusion, the study showed that supplementation with 0.2% oregano can have a positive effect on productive performance and meat quality of rabbits.


      PubDate: 2015-05-04T10:18:35Z
       
  • Evaluation of 3 bromegrass species as pasture: Herbage nutritive value,
           estimated grass dry matter intake and steer performance
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): H.A. Lardner , D. Damiran , J.J. McKinnon
      A 2 year grazing study was conducted to evaluate the effects of grazing meadow bromegrass (Bromus riparius Rehm.; cv. Paddock), smooth bromegrass (B. inermis Leyss.; cv. Carlton), and hybrid bromegrass (B. riparius×B. inermis.; cv. AC Knowles) on herbage nutritive value, dry matter (DM) intake and grazing beef steer performance. Each year, 36 crossbred beef steers (297±6kgBW) (15 month initial age) were randomly allocated to 1 of 3 replicated (n=2) paddocks of each bromegrass species in a “put and take” stocking system from May to July. Herbage samples were collected at start, middle, and end of each grazing period and analyzed for DM, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), in vitro dry matter digestibility (IVDMD) and in situ rumen degradation kinetics. Herbage DM intake was estimated by combining fecal output with herbage in vitro dry matter digestibility. Fecal output was estimated using chromium sesquioxide (Cr2O3) as an external marker. Herbage CP (138±4.2g/kg), NDF (574±5.3g/kg), ADF (340±5.3g/kg), IVDMD (628±3.5g/kg), and effective degradation of herbage DM (35.87±1.07% of DM) did not differ (P>0.05) among the bromegrasses. In all 3 bromegrasses, CP and IVOMD decreased (P<0.05) and NDF and ADF increased (P<0.05) as the grazing season progressed. Over the 60d grazing season, DM intake (10.0±1.7kg/d), ADG (1.0±0.24kg/d), and final BW (329.0±9.2kg) were similar (P>0.05) among steers grazing either bromegrass pasture. The results of this study suggest that meadow bromegrass, smooth bromegrass and hybrid bromegrass are suitable species for grazing providing suitable nutritive value and steer performance for pasture in western Canada.


      PubDate: 2015-05-04T10:18:35Z
       
  • The effect of milk source on body weight and immune status of lambs
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): L.E. Hernández-Castellano , I. Moreno-Indias , A. Morales-delaNuez , D. Sánchez-Macías , A. Torres , J. Capote , A. Argüello , N. Castro
      Milk source is one of the several factors that can affect lamb body weight (BW) and immune status before weaning. The aim of this experiment was to evaluate the effect of milk source (natural rearing method, named NR group, vs. artificial rearing method using a commercial milk replacer, named MR group vs. artificial rearing method using whole powdered cow milk, named CM group) on the BW and immune status of lambs during the milk feeding and weaning period. In this study, 60 lambs were equally divided according to sex and then randomly divided in three groups (NR, MR and CM). Blood plasma was collected to measure the immunoglobulin concentration (IgG and IgM), the chitotriosidase activity and complement system activity, total complement activity (TCA) and alternative complement activity (ACA). Results showed that lambs reared with NR presented, in general, higher BW, IgG, IgM, TCA and ACA than animals reared with MR or CM at 3 and 5 days after birth (P<0.05). These differences, however, disappeared during weaning. At the end of weaning, animals from MR and CM groups showed higher BW than NR lambs (15.28, 16.89 and 17.66kg in NR, MR and CM groups, respectively, P<0.05). In addition, MR and CM groups showed higher IgM concentrations than the NR group (1.05, 1.90 and 1.60mg/mL in NR, MR and CM, respectively, P<0.05). Present findings may improve the management in sheep farms, reducing the expenses of the artificial rearing systems if the described alternative milk feeding source (whole powdered cow milk for human consumption) is selected for feeding lambs reared under an artificial rearing system. Accordingly, these results can be used for increasing the economic benefits of the sheep producers.


      PubDate: 2015-05-04T10:18:35Z
       
  • A meta-analysis of milk production responses to increased net energy
           intake in Scandinavian dairy cows
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): Charlotte Jensen , Søren Østergaard , Ingunn Schei , Jan Bertilsson , Martin Riis Weisbjerg
      The objectives of this analysis were to develop empirical prediction models for milk yield based on cow characteristics and dry matter intake (DMI) or net energy intake (NEL) and to evaluate the effect of breed, parity, stage of lactation and the additional prediction value of using NEL estimates versus DMI estimates for incorporation in future economical optimization models of the energy level in dairy cow rations. Previous Danish response models are outdated due to higher yield capacity of cows and the use of the new Nordic feed evaluation system NorFor since 2011. A data set with 195 treatment mean observations was compiled from original data of 13 trials from Denmark, Norway and Sweden representing the breeds Danish Holstein, Danish Red, Danish Jersey, Norwegian Red and Swedish Red. Total data were grouped into 4 sub datasets according to parity; either primiparous or multiparous and according to stage of lactation; either DIM 1 to 100 (Early) or DIM 101 to 200 (Mid). All analyzed ration characteristics were calculated from NorFor principles or estimated from NorFor feed table values. Data were analyzed using linear mixed effects model with trials as random effect. Residuals were weighted by number of cows in each treatment mean. Best fit model was by use of linear and natural log transformation of NEL intake rather than DMI in the regression, especially when also including the ration concentration of the individual nutrients (g/MJ NEL), neutral detergent fibre, amino acids absorbed in the small intestine and crude fat, in the model. Breed specific responses were parallel and only differed by their intercept. In early lactation for multiparous cows with a mean NEL intake (136MJ) the model predicted an ECM response of 35.4kg and for primiparous cows with mean NEL intake (115MJ) the model predicted an ECM response of 27.8kg. Marginal milk response (kg ECM/MJ NEL) decreased more for multiparous cows (from 0.34 to 0.08) than for primiparous cows (from 0.20 to 0.15) within the observation ranges of NEL intake.


      PubDate: 2015-05-04T10:18:35Z
       
  • Effects of rumen-protected choline with calcium salts of long chain fatty
           acids on milk yield and milk composition of middle and late lactation
           Holstein cows
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): A. Pineda , F.C. Cardoso
      The objective of this study was to evaluate the effect of rumen-protected choline (RPC) supplementation on milk production and milk composition of dairy cows. Fifty lactating multiparous Holstein cows >80 days in milk were randomly assigned to one of two treatments groups. Cows were fed with: (1) control diet (CON; n=25), not supplemented with RPC and (2) supplemented diet (RPC; n=25), supplemented with RPC (115g/cow/d). Control and supplemented cows were fed at ad libitum intake twice daily. Body weight and body condition score were measured weekly. Milk production and dry matter intake were recorded daily. Milk samples were collected twice weekly on week 3, 6, and 9 and analyzed for fat, protein, lactose, urea nitrogen, somatic cell count, fatty acid (FA) composition, and free choline concentration. Plasma was obtained on week 1, 3, 4, 6, 7, and 9 and analyzed for concentrations of free choline and non-esterified fatty acids. Cows remained in the experiment for 9 weeks. Data were analyzed using the MIXED procedure of SAS (v9.4). Higher free choline concentration in plasma (P<0.001) confirmed intake and absorption of RPC by supplemented cows. Dry matter intake (23.6 vs. 23.4kg/d), body weight (704 vs. 703kg), and body condition score (2.86 vs. 2.90; 1–5 scale) were not affected (P>0.05) by RPC supplementation (CON vs. RPC, respectively). There was no difference (P>0.05) on milk yield (36.72 and 36.81kg/d, respectively), 3.5% fat corrected milk, or energy corrected milk between supplemented and non-supplemented cows, respectively. Although production parameters were not affected by RPC supplementation, they were significantly affected (P<0.01) by period and lactation stage. While concentration of de novo and mixed (16:0+cis-9 16:1) FA in milk fat were greater in CON cows, preformed FA were greater in RPC (P<0.05) supplemented cows. Concentration of total saturated FA (P<0.001) was higher in CON cows, whereas total monounsaturated FA (cis and trans) and cis polyunsaturated FA concentrations were greater in RPC cows (P<0.05). Yield of polyunsaturated omega-3 FA was greater when RPC was added to the diet. Although milk production was not affected, supplemental RPC either in middle or late lactation resulted in milk fat composition enriched by long chain polyunsaturated FA.


      PubDate: 2015-05-04T10:18:35Z
       
  • Effects of concentrate supplementation on enteric methane emissions and
           milk production of grazing dairy cows
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): Camila Muñoz , Sara Hube , Jorge M. Morales , Tianhai Yan , Emilio M. Ungerfeld
      Although concentrate supplements in ruminant diets have been recognised as an effective enteric methane mitigation strategy, very few studies have examined the effects of concentrate supplementation on enteric methane emissions under grazing conditions. Twenty four multiparous Holstein Friesian cows were used in a crossover design study to investigate the effects of two concentrate feeding levels across two periods on enteric methane emissions and milk production of grazing dairy cows. Each period had a duration of four weeks (three weeks for diet adaptation and one week for measurements) and no interval in between them. Dietary treatments consisted of two concentrate feeding levels per cow (1 vs. 5kg; as-fed basis) offered daily in equal meals during milking. Enteric methane emissions from cows grazing perennial ryegrass pasture were measured during the final week of each period using the sulphur hexafluoride tracer technique. Milk yield and liveweight were determined daily during each methane measurement period, whereas milk composition and body condition score (BCS) were determined weekly. Daily herbage intake by individual cows during methane measurement weeks was estimated using an energy requirement model and animal records and diet composition. In period 1, cows receiving 5kg concentrate supplement were estimated to reduce herbage intake by 1.8kg DM/d compared to cows receiving 1kg of concentrate, whereas in period 2 cows receiving the 5kg concentrate supplementation were estimated to reduce herbage intake by 4.4kg DM/d, compared to cows receiving 1kg of concentrate. In both periods, milk yield increased with increasing concentrate level, with an average milk response to concentrate supplementation of 0.68kg milk DM/kg concentrate DM over the two periods. Concentrate feeding level had no effect on milk fat, protein or total solids contents. In period 2, lactose content increased in cows offered 5kg/d concentrate. Increasing concentrate feeding level increased liveweight and BCS in period 1, but not in period 2. Feeding 5kg of concentrate supplement increased enteric methane emission by 34g/d in period 1 (323 vs. 357g/d) and 41g/d in period 2 (349 vs. 390g/d) compared to 1kg of concentrate supplement. However, enteric methane emission per unit of estimated feed intake (dry matter or gross energy) or milk output (gross or energy corrected) was not affected by level of concentrate supplementation. It was concluded that under generous grazing conditions (high allowance of good quality herbage) a moderate increase in concentrate supplementation resulted in a simultaneous increase in milk yield and enteric methane emission, so that enteric methane emission per unit of milk yield was unaffected. Thus, a moderate level of concentrate supplementation of dairy cows grazing pastures of high digestibility would not be an effective enteric methane mitigation strategy.


      PubDate: 2015-05-04T10:18:35Z
       
  • Genetic diversity and phylogeographic structure of sixteen Mediterranean
           chicken breeds assessed with microsatellites and mitochondrial DNA
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): S. Ceccobelli , P. Di Lorenzo , H. Lancioni , L.V. Monteagudo Ibáñez , M.T. Tejedor , C. Castellini , V. Landi , A. Martínez Martínez , J.V. Delgado Bermejo , J.L. Vega Pla , J.M. Leon Jurado , N. García , G. Attard , A. Grimal , S. Stojanovic , K. Kume , F. Panella , S. Weigend , E. Lasagna
      The genetic diversities and relationships among 16 local breeds of chicken originating from five countries (Italy, Spain, Serbia, Albania and Republic of Malta) within the Mediterranean basin were assessed by sequencing part of the mitochondrial DNA (mtDNA) D-loop region and by genotyping individuals at 27 autosomal microsatellite loci. The aim was to study the microevolution of chicken on the northern shores of the Mediterranean and to determine their present genetic status. A 506bp fragment of the mtDNA control region was sequenced in 160 individual DNA samples. The mtDNA sequence polymorphisms nomenclature that is normally used in these studies suggests that the Mediterranean chicken breeds under investigation are related to haplogroup E. A total of 465 blood samples were collected and utilised for microsatellite analysis. Six breeds (Ancona, Livornese Bianca—Italy; Pita Pinta Asturiana, Gallina de Sobrarbe—Spain; Albanian population—Albania; and the Maltese Black—Malta) showed significant high levels of inbreeding. About 22% of the total genetic variation observed was due to variability between populations. STRUCTURE analysis confirmed the breed variability result (F ST=0.22) also observed in the Neighbor-Net dendrogram. These results strongly allude that the 16 Mediterranean chicken breeds studied originated from three distinct maternal lineages and retain moderate levels of autosomal genetic diversity.


      PubDate: 2015-05-04T10:18:35Z
       
  • Genomic–polygenic evaluation of multibreed Angus–Brahman
           cattle for postweaning ultrasound and weight traits with actual and
           imputed Illumina50k SNP genotypes
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): M.A. Elzo , M.G. Thomas , D.D. Johnson , C.A. Martinez , G.C. Lamb , D.O. Rae , J.G. Wasdin , J.D. Driver
      The objectives were to estimate additive genetic variance fractions for 4 postweaning ultrasound and weight traits explained by 46,839 actual and imputed SNP genotypes, to compare rankings of calf additive genetic predictions from genomic–polygenic (GP), genomic (G), and polygenic (P) models, and to assess trends for GP, G, and P predicted additive genetic values as functions of calf Brahman fractions in a multibreed Angus–Brahman population. Traits were postweaning ultrasound ribeye area (UREA), backfat thickness (UBF), and percent intramuscular fat (UPIMF), and weight (UW). Phenotypes and Illumina3k genotypes were from 812 bull, heifer, and steer calves housed at the Feed Efficiency Facility of the University of Florida from 2006 to 2010. Program Findhap2 was used to impute from 2899 Illumina3k SNP to 46,839 Illumina50k SNP using a reference population of 828 Brangus heifers. Fixed effects for all models were contemporary group (year-pen), age of dam, sex of calf, age of calf, Brahman fraction of calf, and heterozygosity of calf. Random effects were additive SNP (GP and G models), additive polygenic (GP and P models), and residual. Software GS3 was used to compute variance components and heritabilities, and additive genetic predictions. Additive genetic variance fractions explained by the 46,839 actual and imputed SNP were 0.17 for UREA, 0.32 for UBF, 0.25 for UPIMF, and 0.19 for UW. Heritabilities were 0.33 for UREA, 0.22 for UBF, 0.43 for UPIMF, and 0.54 for UW. These additive genetic variance fractions were 1.8, 1.0, 4.4, and 2.1 times greater and heritabilities were 1.0, 1.2, 1.0, and 1.2 times greater than those obtained for these 4 traits using only the 2899 Illumina3k SNP. Rank correlations between EBV from GP and P models were the highest (0.93 to 0.96), followed by those between EBV from GP and G models (0.81 to 0.94), and by those between EBV from G and P models (0.66 to 0.81). Regression coefficients of EVB on Brahman fraction were small for all traits and models indicating that animals of comparable EBV existed in all breed groups. Imputation from Illumina3k to 50k increased the explained fraction of additive SNP variance resulting in higher rank correlations between additive genetic predictions from G and GP, and from G and P models for all ultrasound traits in this Angus–Brahman multibreed population.


      PubDate: 2015-05-04T10:18:35Z
       
  • Body condition score of Nelore cows and its relation with mature size and
           gestation length
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): D.D. Silveira , F.R.P. Souza , C.C. Brauner , D.R. Ayres , F.A. Silveira , N.J.L. Dionello , A.A. Boligon
      The objective of this study was to evaluate the genetic variability of body condition score (BCS) in Nelore cows, and analyze its genetic correlations with mature weight (MW), mature height (MH) and gestation length (GL), in order to obtain information supporting the possible use of this score in breeding programs. The BCS was recorded on pregnancy diagnosis and ranged from 1 (very thin) to 5 (extremely fat). Adjusted means for MW, MH and GL according to the BCS classes were obtained using an univariate mixed model for each trait. Bayesian Inference using Gibbs Sampling was applied to estimate (co)variances components and genetic and phenotypic correlations, in two-trait analyses, considering a threshold animal model for BCS and a linear animal model for the other traits. Adjusted means for MW, MH and GL showed significant variation (p<0.0001) among BCS classes, indicating that cows with higher BCS have greater mature size, assessed by MW and MH measures, and longer GL than those with lower BCS. The BCS showed genetic variability, with posterior mean heritability of 0.23±0.05. Genetic correlations between the BCS with MW, MH and GL were 0.41±0.04; −0.06±0.03 and 0.10±0.02, respectively. Selection based on BCS should result in gain for body condition and, by indirect response, in changes in the same direction for cows MW. However, selection for BCS has little or no effect on MH and GL. So that BCS can effectively be used as a selection criterion of beef cows, further studies should be performed in order to obtain genetic associations with other economic traits.


      PubDate: 2015-05-04T10:18:35Z
       
  • Editorial Board
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175




      PubDate: 2015-05-04T10:18:35Z
       
  • Genome-wide association study for somatic cell score in Argentinean dairy
           cattle
    • Abstract: Publication date: May 2015
      Source:Livestock Science, Volume 175
      Author(s): Juan P Nani , Maria A Raschia , Mario A Poli , Luis F Calvinho , Ariel F Amadio
      This study aimed to understand the genomic architecture of Argentinean dairy herds by measuring linkage disequilibrium (LD) and identifying loci associated with parameters calculated from somatic cell count (SCC). Phenotypic data consisted of 3530 SCC records from 544 Holstein and Holstein x Jersey cows owned by a single dairy company located in the Central dairy area of Argentina. SCC was recorded every 40 days. After quality control, genotypic data consisted in 38,872 single nucleotide polymorphisms (SNP). The squared correlation of the alleles at two loci (r 2) was computed for all SNP pairs on each chromosome. At marker distances less than 10kb the average r 2 was 0.40. Between 40 and 50kb the average r 2 was 0.25 and 0.18 for 100kb apart. Three different variables were calculated from the somatic cell score (SCS): the arithmetic mean (AM), the maximum value (MAX) and the arithmetic mean of the top 3 values (TOP3). Few significant SNP associations were found. As expected, polygenic traits such as SCC are influenced by multiple loci throughout the genome, each with a relatively small effect. AM on one side and TOP3 and MAX on the other, showed different SNP associated showing that they capture different aspects of mastitis response. AM was significantly associated with two SNP: ARS-BFGL-NGS-114608 (BTA1) and Hapmap60306-rs29023088 (BTA5). MAX and TOP3 were significantly associated with four SNP: ARS-BFGL-NGS-107594, ARS-BFGL-NGS-104220 (BTA10), BTA-43543-no-rs (BTA18) and ARS-BFGL-NGS-109705 (BTA26). MAX and TOP3 were equivalent phenotypic variables to be used in a GWAS. These results contribute to gain insight into the genomic regions influencing the SCC in Argentinean herds.


      PubDate: 2015-05-04T10:18:35Z
       
  • Growth performance, apparent nutrient digestibility, intestinal morphology
           and carcass traits of broiler chickens fed dry, wet and fermented-wet feed
           
    • Abstract: Publication date: Available online 2 May 2015
      Source:Livestock Science
      Author(s): O.S. Akinola , A.O. Onakomaiya , J.A. Agunbiade , A.O. Oso
      This study seeks to investigate the growth performance, intestinal morphology, carcass traits and apparent nutrient digestibility of broiler chickens fed with dry, wet and fermented-wet feed. Three experimental diets were formulated in this study. Diet 1 was dry mash feed. Diet 2 was wet mash feed in a 1:1.3 mix with water. Diet 3, was fermented-wet mash feed in a 1: 1.3 mix with water which was fermented for 24h in sealed plastic polythene bags prior to feeding. A total of 192 two-weeks-old broilers (Marshal strain) were randomly assigned to the experimental diets in a completely randomized design (CRD). Each treatment group was replicated four times with 16 birds per replicate. Each dietary treatment was fed immediately to the birds after re-constitution. Fermentation of the feed reduced (P<0.05) the pH from 6.61 to 4.37. Birds fed fermented-wet and wet mash recorded higher (P<0.05) final live weight and weight gain. Feed intake and feed conversion ratio were not affected (P>0.05) by wet and fermented-wet fed birds compared to the dry fed birds. Mortality was not affected by dietary treatment imposed. Apparent organic matter digestibility was higher (P<0.05) in birds fed fermented-wet feed when compared to birds fed with dry and wet feed. Intestinal villus morphology and carcass measurement were not affected (P>0.05) by the treatment imposed. However, birds fed wet feed showed lower (P<0.05) gizzard weight when compared to birds fed fermented-wet feed. Birds fed with fermented-wet mash recorded higher (P<0.05) abdominal fat than those fed with dry mash. The results of this study indicated fermented-wet feeding improved apparent organic matter digestibility with a resultant improved growth performance of broiler chicken.


      PubDate: 2015-05-04T10:18:35Z
       
  • Prediction of the Ym factor for livestock from on-farm accessible data
    • Abstract: Publication date: Available online 2 May 2015
      Source:Livestock Science
      Author(s): G. Jaurena , J.M. Cantet , J.I. Arroquy , R.A. Palladino , M. Wawrzkiewicz , D. Colombatto
      Methane emission factor (Ym) is directly involved to calculate the worldwide livestock methane inventories, hence it is important to refine the estimation of this parameter for different livesctock production systems. The purpose of this work was to generate refined mathematical models to predict CH4 emissions from an extensive compilated database at on-farm level and to compare them with different models already available in the literature. Methane emission predictive models (expressed as Ym, % gross energy intake; and methane production, CH 4 p, g an−1 d−1) where fitted taken into account the production system, the livestock type and the feed characteristics available at on-farm level within a reasonable uncertainty range. In order to develop the models, only easy available paramenters were selected to fit new mathematical models. Hence, the full model included: ruminant types (beef cattle, dairy cattle, and sheep), fibre sources (fresh forage, conserved forage, and straw) and concentrate levels (DM basis) in the diet (low, <35%; intermediate, 35–65%; high, >65%). Full models were assessed by the Bayesian Information Criterion (BIC) and terms that did not reach significance level (P≤0.05) were dropped from the model. Furthermore, predicted results were assessed through correlation and regression analysis considering the model significance. Models developed in this study were compared by the degree of adjustment of a simple regression. Additive and technique terms were initially dropped from the full model used to predict Ym because they did not have effect in the prediction (P>0.10). Therefore, the final equation for Model 1 was: Ym(a)=Intercept – 0.243 (± 0.051) ×DMI (kg d−1)+5.9×10−3 (±1.17×10−3) ×NDF (g kg−1 DM−1)+5.7×10−3 (±1.63×10−3)×DMD (g kg−1 MS−1) (BIC=559). All terms of this model, intercept factor (type of cattle × source of fibre × level of concentrate), DMI, NDF, and DMD were significant (P<0.0001). DMI was the term with the greatest weight in the model. The predicted Ym value decreased about 0.243 percentage units (P<0.0001) per each additional kg in DMI. When the equation was compared with previous publicated models, our model showed a satifactory degree of fitting. In conclusion, this new model improved the estimation of the Ym factor from beef and dairy production systems, using different forage quality characteristics from on-farm level to increase precision.


      PubDate: 2015-05-04T10:18:35Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2015