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D P Berry - One of the best experts on this subject based on the ideXlab platform.

  • prediction of Genetic Merit for live weight and body condition score in dairy cows using routinely available linear type and carcass data
    Journal of Dairy Science, 2021
    Co-Authors: D P Berry, R D Evans, M M Kelleher
    Abstract:

    ABSTRACT Accurate estimates of Genetic Merit for both live weight and body condition score (BCS) could be useful additions to both national- and herd-breeding programs. Although recording live weight and BCS is not technologically arduous, data available for use in routine Genetic evaluations are generally lacking. The objective of the present study was to explore the usefulness of routinely recorded data, namely linear type traits (which also included BCS but only assessed visually) and carcass traits in the pursuit of Genetic evaluations for both live weight and BCS in dairy cows. The data consisted of on-farm records of live weight and BCS (assessed using both visual and tactile cues) from 33,242 dairy cows in 201 commercial Irish herds. These data were complemented with information on 6 body-related linear type traits (i.e., stature, angularity, chest width, body depth, BCS, and rump width) and 3 cull cow carcass measures (i.e., carcass weight, conformation, and fat cover) on a selection of these animals plus close relatives. (Co)variance components were estimated using animal linear mixed models. The Genetic correlation between the type traits stature, angularity, body depth, chest width, rump width, and visually-assessed BCS with live weight was 0.68, −0.28, 0.43, 0.64, 0.61, and 0.44, respectively. The Genetic correlation between angularity and BCS measured on farm (based on both visual and tactile appraisal) was −0.79; the Genetic and phenotypic correlation between BCS assessed visually as part of the linear assessment with BCS assessed by producers using both tactile and visual cues was 0.90 and 0.27, respectively. The Genetic (phenotypic) correlation between cull cow carcass weight and live weight was 0.81 (0.21), and the Genetic (phenotypic) correlation between cull cow carcass fat cover and BCS assessed on live cows was 0.44 (0.12). Estimated breeding values (EBV) for live weight and BCS in a validation population of cows were generated using a multitrait evaluation with observations for just the type traits, just the carcass traits, and both the type traits and carcass traits; the EBV were compared with the respective live weight and BCS phenotypic observations. The regression of phenotypic live weight on its EBV from the multitrait evaluations was 1.00 (i.e., the expectation) when the EBV was generated using just linear type trait data, but less than 1 (0.83) when using just carcass data. However, the regression changed across parities and stages of lactation. The partial correlation (after adjusting for contemporary group, parity by stage of lactation, heterosis, and recombination loss) between phenotypic live weight and EBV for live weight estimated using the 3 different scenarios (i.e., type only, carcass only, type plus carcass) ranged from 0.38 to 0.43. Although the prediction of phenotypic BCS from its respective EBV was relatively good when using just the linear type trait data (regression coefficient of 0.83 with a partial correlation of 0.22), the predictive ability of BCS EBV based on just carcass data was poor and should not be used. Overall, linear type trait data are a useful source of information to predict live weight and BCS with minimal additional predictive value from also including carcass data. Nonetheless, in the absence of linear type trait data, information on carcass traits can be useful in predicting Genetic Merit for mature cow live weight. Prediction of cow BCS from cow carcass data is not recommended.

  • short communication differences in Genetic Merit for visually assessed body condition score materialises as phenotypic differences in tactile based body condition score in commercial dairy cows
    Animal, 2021
    Co-Authors: D P Berry, M M Kelleher
    Abstract:

    Abstract Body condition score (BCS) is a known risk factor for cow health and well-being. Many different BCS scales and systems for assessment exist;while the scales used for assessing BCS vary, differences in how BCS is assessed (i.e., visual versus visual plus tactile) and the extent of training and experience of the assessor (i.e., professional linear classifiers versus producers) also contributes to the underlying variability. Registered dairy cows globally are routinely assessed for linear type traits which describe biological extremes in the morphological attributes; BCS and a correlated trait angularity are within this suite of traits assessed. These linear-type data are used to generate estimates of Genetic Merit (predicted transmitting ability), but how these estimates manifest themselves as phenotypic differences when assessed by producers on commercial multiparous cows has never been quantified. To evaluate this, 58 440 phenotypic BCS records from 48 823 lactations in 38 608 cows were used. Associations were undertaken using linear mixed models relating phenotypic BCS to Genetic Merit after accounting for nuisance factors. Differences in Genetic Merit for either BCS or angularity (assessed visually by professionals on a 1 to 9 scale just once during lactation in primiparous registered cows) translated to phenotypic difference in BCS (assessed by producers using both tactile and visual assessment on a 1 to 5 scale across lactation in commercial dairy cows). The partial correlation between test phenotypic BCS and Genetic Merit for either BCS or angularity was 0.13 and  0.10, respectively. Based on the model coefficients estimated in the present study, the mean expected difference in phenotypic BCS on a 1 to 5 scale between the top and bottom 10% on Genetic Merit for BCS or angularity was 0.28 and 0.31 units, respectively. Results from the present study clearly provide confidence that Genetic Merit for BCS or angularity based on a single visual assessment in primiparous cows is useful to breed for cows of better body condition, irrespective of stage of lactation or parity.

  • how herd best linear unbiased estimates affect the progress achievable from gains in additive and nonadditive Genetic Merit
    Journal of Dairy Science, 2019
    Co-Authors: F L Dunne, M M Kelleher, S Mcparland, Siobhan W Walsh, D P Berry
    Abstract:

    Sustainable dairy cow performance relies on coevolution in the development of breeding and management strategies. Tailoring breeding programs to herd performance metrics facilitates improved responses to breeding decisions. Although herd-level raw metrics on performance are useful, implicitly included within such statistics is the mean herd Genetic Merit. The objective of the present study was to quantify the expected response from selection decisions on additive and nonadditive Merit by herd performance metrics independent of herd mean Genetic Merit. Performance traits considered in the present study were age at first calving, milk yield, calving to first service, number of services, calving interval, and survival. Herd-level best linear unbiased estimates (BLUE) for each performance trait were available on a maximum of 1,059 herds, stratified as best, average, and worst for each performance trait separately. The analyses performed included (1) the estimation of (co)variance for each trait in the 3 BLUE environments and (2) the regression of cow-level phenotypic performance on either the respective estimated breeding value (EBV) or the heterosis coefficient of the cow. A fundamental assumption of Genetic evaluations is that 1 unit change in EBV equates to a 1 unit change in the respective phenotype; results from the present study, however, suggest that the realization of the change in phenotypic performance is largely dependent on the herd BLUE for that trait. Herds achieving more yield, on average, than expected from their mean Genetic Merit, had a 20% greater response to changes in EBV as well as 43% greater Genetic standard deviation relative to herds within the worst BLUE for milk yield. Conversely, phenotypic performance in fertility traits (with the exception of calving to first service) tended to have a greater response to selection as well as a greater additive Genetic standard deviation within the respective worst herd BLUE environments; this is suggested to be due to animals performing under more challenging environments leading to larger achievable gains. The attempts to exploit nonadditive Genetic effects such as heterosis are often the basis of promoting cross-breeding, yet the results from the present study suggest that improvements in phenotypic performance is largely dependent on the environment. The largest gains due to heterotic effects tended to be within the most stressful (i.e., worst) BLUE environment for all traits, thus suggesting the heterosis effects can be beneficial in mitigating against poorer environments.

  • cattle stratified on Genetic Merit segregate on carcass characteristics but there is scope for improvement
    Translational animal science, 2019
    Co-Authors: D P Berry, T Pabiou, Denis Brennan, Patrick J Hegarthy, Michelle M Judge
    Abstract:

    The study objective was to quantify the ability of Genetic Merit for a generated carcass index to differentiate animals on primal carcass cut weights using data from 1,446 herds on 9,414 heifers and 22,413 steers with weights for 14 different primal carcass cuts (plus 3 generated groups of cuts). The carcass Genetic Merit index was compromised of carcass weight (positive weight), conformation (positive weight), and fat score (negative weight), each equally weighted within the index. The association analyses were undertaken using linear mixed models; models were run with or without carcass weight as a covariate. In a further series of analyses, carcass weight and carcass fat score were both included as covariates in the models. Whether the association between primal cut yield and carcass weight differed by Genetic Merit stratum was also investigated. Genetic Merit was associated (P < 0.001) with the weight of all cuts evaluated even when adjusted to a common carcass weight (P < 0.01); when simultaneously adjusted to a common carcass weight and fat score, Genetic Merit was not associated with the weight of the cuberoll or the group cuts termed minced-meat. The weight of the different primal cuts increased almost linearly within increasing Genetic Merit, with the exception of the rump and bavette. The difference in mean primal cut weight between the very low and very high Genetic Merit strata, as a proportion of the overall mean weight of that cut in the entire data set, varied from 0.05 (bavette) to 0.28 (eye of round); the average was 0.17. Following adjustment for differences in carcass weight, there was no difference in cut weight between the very low and very high strata for the rump, chuck tender, and mince cut group; the remaining cuts were heavier in the higher index animals with the exception of the cuberoll and bavette, which were lighter in the very high index animals. The association between carcass weight and the weight of each of the evaluated primal cuts differed (P < 0.05) by Genetic Merit stratum for all cuts evaluated with the exception of the rump, striploin, and brisket as well as the group cuts of frying and mincing. With the exception of these 5 primal (group) cuts, the regression coefficients of primal cut weight on carcass weight increased consistently for all traits with increasing Genetic Merit stratum, other than for the fillet, cuberoll, bavette, chuck and neck, and heel and shank.

  • predicted carcass meat yield and primal cut yields in cattle divergent in Genetic Merit for a terminal index
    Translational Animal Science, 2019
    Co-Authors: Stephen M Connolly, A R Cromie, Roy D Sleator, D P Berry
    Abstract:

    Several studies have clearly demonstrated the favorable impact of Genetic selection on increasing beef cattle performance within the farm gate. Few studies, however, have attempted to quantify the value of Genetic selection to downstream sectors of the beef industry, such as the meat processing sector. The objective of the current study was to characterize detailed carcass attributes of animals divergent in Genetic Merit for a terminal index as well as individual measures of Genetic Merit for carcass weight, conformation, and fat. The data used consisted of 53,674 young bulls and steers slaughtered between the years 2010 and 2013 in multiple Irish processing plants. All animals had a Genetic evaluation as well as phenotypic measures of carcass characteristics. A terminal index, based on pedigree index for calving performance, feed intake, and carcass traits, calculated from the Irish national Genetic evaluations, was obtained for each animal. Animals were categorized into four terminal index groups based on Genetic Merit estimates derived prior to the expression of the carcass phenotype by the animal. The association between Genetic Merit for terminal index with predicted phenotypic carcass red meat yield, carcass fat, carcass bone, and carcass composition, as well as between Genetic Merit for carcass weight, conformation, and fat with predicted phenotypic carcass red meat yield and composition were all quantified using linear mixed models. A greater terminal index value was associated with, on average, heavier phenotypic weights of each wholesale cut category. A greater terminal index value was also associated with a greater weight of meat and bone, but reduced carcass fat. Relative to animals in the lowest 25% Genetic Merit group, animals in the highest 25% Genetic Merit group had, on average, a greater predicted yield of very high value cuts (4.52 kg), high value cuts (13.13 kg), medium value cuts (6.06 kg), low value cuts (13.25 kg) as well as more total meat yield (37 kg). The results from the present study clearly signify a benefit to meat processers from breeding programs for terminal characteristics; coupled with the previously documented benefits to the producer, the benefits of breeding programs across the entire food production chain are obvious.

S T Butler - One of the best experts on this subject based on the ideXlab platform.

  • Genetic Merit for fertility traits in holstein cows vi oocyte developmental competence and embryo development
    Journal of Dairy Science, 2019
    Co-Authors: S G Moore, Sean B Cummins, P Lonergan, Solomon Mamo, T Fair, S T Butler
    Abstract:

    ABSTRACT The hypothesis of this study was that cows with good Genetic Merit for fertility traits (Fert+) would produce oocytes and embryos of greater quality than cows with poor Genetic Merit for fertility traits (Fert−) and that mRNA expression of candidate genes would reflect the observed differences in quality. The aim of the study, therefore, was to determine the effect of Genetic Merit for fertility traits on morphological classification and mRNA abundance of key genes in immature oocytes and cumulus cells following ovum pick-up and in embryos following superovulation, artificial insemination (AI), and uterine flushing. In experiment 1, 17 Fert+ and 11 Fert− cows, ranging from 54 to 84 d in milk, were submitted to ovum pick-up on 4 occasions during a 2-wk period. Recovered cumulus–oocyte complexes (COC) were morphologically graded. Oocytes and cumulus cells were separated, and mRNA abundance of genes associated with oocyte developmental competence was measured. There was no effect of genotype on the distribution of COC grades or on the mRNA abundance of the candidate genes in grade 1 COC. In experiment 2, 20 Fert+ and 19 Fert− cows, ranging from 71 to 189 d in milk, were submitted to superovulation and AI. The uteri of cows that responded to the superovulation protocol (17 Fert+ and 16 Fert− cows) were nonsurgically flushed 7 d postovulation. Recovered embryos were morphologically graded, and mRNA abundance of genes associated with embryo development was measured in grade 1 blastocysts. The response to the superovulation protocol was assessed by counting the number of codominant follicles on the day of AI, which was similar for both genotypes (22.0 ± 9.7 and 19.8 ± 8.2 for Fert+ and Fert− cows, respectively). There was no effect of genotype on the proportion of transferable embryos recovered or on the mRNA abundance of the candidate genes tested in the grade 1 blastocysts. Of the total embryos classified as blastocysts, however, the Fert+ cows tended to have a greater proportion of grade 1 blastocysts compared with Fert− cows (90% vs. 64%, respectively). In conclusion, Genetic Merit for fertility traits had a no effect on mRNA abundance of the candidate genes that were examined in immature oocytes and cumulus cells and in embryos recovered after superovulation. The observed differences in morphological blastocyst quality following superovulation would suggest that the superior reproductive performance of Fert+ cows could arise during the later stages of embryo development from d 7 until maternal recognition of pregnancy.

  • follicular fluid and serum metabolites in holstein cows are predictive of Genetic Merit for fertility
    Reproduction Fertility and Development, 2017
    Co-Authors: T Fair, S G Moore, Aoife Ogorman, Lorraine Brennan, S T Butler
    Abstract:

    The aims of the present study were to: (1) characterise the metabolome of follicular fluid and serum in dairy cows with similar Genetic Merit for milk production but with extremes of good (Fert+) or poor (Fert–) Genetic Merit for fertility; and (2) identify potential biomarkers of dairy cow fertility. Follicular fluid from the first wave dominant follicle and serum were collected on Day 7 of the oestrous cycle. The most pronounced effect of genotype was noted in the serum, where the abundance of total polyunsaturated fatty acids and n-6 polyunsaturated fatty acids was greater in Fert+ cows, and the abundance of total saturated fatty acids was greater in Fert– cows. The abundance of nine fatty acids (arachidic acid, heneicosanoic acid, myristic acid, behenic acid, myristoleic acid, heptadecenoic acid, cis-11-eicosanoic acid, nervonic acid and γ-linolenic acid) in follicular fluid was affected by genotype. Concentrations of cysteine, leucine, ornithine, proline and tyrosine in follicular fluid, and asparagine, creatinine, cysteine, methionine, proline and valine in serum, were also affected by genotype. Receiver operating characteristic curve analysis indicated that the follicular fluid and serum fatty acids and follicular fluid amino acids that were significantly affected by genotype were highly predictive of fertility genotype.

  • Genetic Merit for fertility traits in holstein cows iv transition period uterine health and resumption of cyclicity
    Journal of Dairy Science, 2014
    Co-Authors: P Lonergan, S G Moore, T Fair, S T Butler
    Abstract:

    Abstract The objective of this study was to monitor the dry matter intake (DMI), metabolic status, uterine health, and resumption of cyclicity in cows with similar Genetic Merit for milk production traits but with either good (Fert+) or poor Genetic Merit (Fert−) for fertility traits. Twenty-six cows were enrolled in the study and data are reported for 15 Fert+ and 10 Fert− cows that completed the study. All cows received a total mixed ration diet during early lactation and were turned out to pasture in late spring. Dry matter intake was recorded daily from wk −2 to 5 relative to parturition. Blood metabolites and metabolic hormones were measured from wk −2 to 8 relative to parturition. Milk production, body condition score, and body weight until wk 35 of lactation are reported. To monitor uterine health, vaginal mucus was scored weekly on a scale of 0 (no pus) to 3 (≥50% pus) from parturition to wk 8 and uterine polymorphonuclear neutrophil count was measured at wk 3 and 6 postpartum. Prepartum DMI was similar between genotypes, but Fert+ cows had significantly greater DMI than Fert− cows (19.7 vs. 16.8kg of dry matter/d) during the postpartum period. Energy balance at wk 1 was significantly greater in Fert+ cows than in Fert− cows [2.3 vs. −1.12 unite fourragere lait (UFL)/d]. The Fert+ cows had significantly greater daily milk solids production (1.89 vs. 1.74kg/d) and tended to have greater daily milk yield (24.2 vs. 22.3kg/d). The Fert+ cows had significantly greater mean circulating insulin-like growth factor-I (102.62 vs. 56.85ng/mL) and tended to have greater mean circulating insulin (3.25 vs. 2.62μIU/mL) compared with Fert− cows from wk −2 to 8 relative to parturition. Mean circulating glucose (3.40 vs. 3.01mmol/L) concentrations were significantly greater in Fert+ cows compared with Fert− cows from wk −2 to 3 relative to parturition. The Fert+ cows maintained significantly greater mean body condition score throughout lactation compared with Fert− cows (2.98 vs. 2.74 units). Moreover, Fert+ cows had better uterine health compared with Fert− cows, as evidenced by lower weekly vaginal mucus scores from wk 2 to 6 postpartum and, based on uterine cytology, smaller proportions were classified as having endometritis at wk 3 (0.42 vs. 0.78) and 6 (0.25 vs. 0.75). Also, a significantly greater proportion of Fert+ cows had resumed cyclicity by wk 6 postpartum (0.86 vs. 0.20) compared with Fert− cows. Hence, we report for the first time that Genetic Merit for fertility traits is associated with postpartum uterine health status. Superior uterine health and earlier resumption of cyclicity may be mediated through differences in DMI, energy balance, insulin, insulin-like growth factor-I, and body condition score profiles. Importantly, phenotypic improvement in fertility traits was achieved without antagonizing milk production.

  • Genetic Merit for fertility traits in holstein cows iii hepatic expression of somatotropic axis genes during pregnancy and lactation
    Journal of Dairy Science, 2012
    Co-Authors: Sean B Cummins, Sinead M Waters, A C O Evans, P Lonergan, S T Butler
    Abstract:

    Abstract The objective of this study was to characterize the circulating concentrations of insulin-like growth factor-I (IGF-I) and the hepatic expression of key genes regulating the somatotropic axis in cows divergent in Genetic Merit for fertility traits but with similar Genetic Merit for milk production traits. A total of 11 cows with good Genetic Merit for fertility (Fert+) and 12 cows with poor Genetic Merit for fertility (Fert−) underwent liver biopsy by percutaneous punch technique on d 20 (±6.7 d) prepartum and on d 2 (±1.5 d), d 58 (±3.7 d), d 145 (±13 d), and d 245 (±17.1 d) postpartum. Total RNA was isolated and the mRNA expression of growth hormone receptor ( GHR 1A and GHRtot ), IGF-I , janus tyrosine kinase 2 ( JAK2 ), signal transducer and activator of transcription 5B ( STAT5B ), suppressor of cytokine signaling 3 ( SOCS-3 ), acid-labile subunit ( ALS ), and IGF-binding proteins ( IGFBP1 to IGFBP6 ) were measured by real-time quantitative PCR. During lactation, the circulating concentrations of IGF-I were 34% greater in Fert+ cows. The Fert+ cows had increased mean expression of IGF-I mRNA during the study; however, the difference in IGF-I mRNA abundance between Fert+ and Fert− cows was most pronounced at d 145 and 245. The expression of IGFBP3 and ALS transcript was similar in Fert+ and Fert− cows for the duration of the study. The Fert− cows, however, had greater expression of IGFBP2 , IGFBP4 , IGFBP5 , and IGFBP6 . Genotype had no effect on mRNA abundance of GHR 1A , STAT5B , JAK2 , or SOCS-3 . Genetic Merit for fertility traits affects hepatic expression of key genes of the somatotropic axis regulating the synthesis, bioavailability, and stability of circulating IGF-I.

  • Genetic Merit for fertility traits in holstein cows i production characteristics and reproductive efficiency in a pasture based system
    Journal of Dairy Science, 2012
    Co-Authors: D P Berry, R D Evans, Sean B Cummins, A C O Evans, P Lonergan, S T Butler
    Abstract:

    Abstract The objective of the present study was to characterize the phenotypic performance of cows with similar proportions of Holstein Genetics, similar Genetic Merit for milk production traits, but with good (Fert+) or poor (Fert−) Genetic Merit for fertility traits. Specifically, we tested the hypothesis that cows with a negative estimated breeding value for calving interval would have superior fertility performance and would have detectable differences in body reserve mobilization and circulating concentrations of metabolic hormones and metabolites compared with cows that had a positive estimated breeding value for calving interval. For the duration of the study, cows were managed identically as a single herd in a typical grass-based, spring-calving production system. A total of 80 lactation records were available from 26 Fert+ and 26 Fert− cows over 2 consecutive years (2008 and 2009). During yr 1, cows were monitored during a 20-wk breeding season to evaluate reproductive performance. Milk production, body condition score (scale 1 to 5), body weight, grass dry matter intake, energy balance, and metabolic hormone and metabolite data were collected during both years. The Fert+ cows had greater daily milk yield (19.5 vs. 18.7kg/d), shorter interval from calving to conception (85.6 vs. 113.8 d), and fewer services per cow (1.78 vs. 2.83). No difference between groups in grass dry matter intake, energy balance, or body weight was observed. The Fert+ cows maintained greater BCS during mid (2.84 vs. 2.74 units) and late lactation (2.82 vs. 2.73 units). Circulating concentrations of insulin-like growth factor-I were greater throughout the gestation-lactation cycle in Fert+ cows (148.3 vs. 128.2ng/mL). The Fert+ cows also had greater circulating concentrations of insulin during the first 4 wk of lactation (1.71 vs. 1.24μIU/mL). Analysis of records from national herd data verified the association between Genetic Merit for fertility traits and phenotypic reproductive performance; Fert+ cows (n=2,436) required 11.1 d less to recalve than did Fert− cows (n=1,388), and the percentage of cows that successfully calved for the second time within 365 and 400 d of the first calving was 8 and 13% greater for Fert+ compared with Fert− cows, respectively. These results demonstrate that Genetic Merit for fertility traits had a pronounced effect on reproductive efficiency, BCS profiles, and circulating concentrations of insulin-like growth factor-I.

Luc Delaby - One of the best experts on this subject based on the ideXlab platform.

  • ability of dairy cows to be inseminated according to breed and Genetic Merit for production traits under contrasting pasture based feeding systems
    Animal, 2017
    Co-Authors: Nicolas Bedere, Catherine Disenhaus, Vincent Ducrocq, Segolene Leurentcolette, Luc Delaby
    Abstract:

    Strong Genetic selection on production traits is considered to be responsible for the declined ability of dairy cows to ensure reproduction. The present study aimed to quantify the effect of Genetic characteristics (breeds and Genetic Merit for production traits) and feeding systems (FS) on the ability of dairy cows to be inseminated. An experiment was conducted during 9 years on Normande and Holstein cows assigned to contrasted pasture-based FS. Diets were based on maize silage in winter and grazing plus concentrate in spring in the High FS; and on grass silage in winter and grazing with no concentrate during spring in the low FS. Within breed, cows were classified into two Genetic groups with similar estimated breeding values (EBV) for milk solids: cows with high EBV for milk yield were included in a Milk-Group and those with high EBV for fat and protein contents were included in a Content-Group. Holstein produced more milk throughout lactation than Normande cows (+2294 kg in the High FS and +1280 kg in the Low FS, P<0.001) and lost more body condition to nadir (-1.00 point in the High FS and -0.80 kg in the Low FS, P<0.001). They also showed a poorer ability to be inseminated because of both a delayed commencement of luteal activity (CLA) and delayed first service (more days from start of the breeding season to first service, DAI1). Cows in the Milk-Group produced more milk than cows in the Content-Group, but milk solids production was similar. Cows in the Content-Group had earlier CLA than cows in the Milk-Group (P<0.01). Genetic group neither affected ovulation detection rate nor DAI1. Within breed and FS, cows with high Genetic Merit for milk yield had later CLA and DAI1. Cows in the High FS produced more milk and lost less condition to nadir than cows in the Low FS. FS did not affect dairy cows' ability to be inseminated. However, cows with higher milk protein content, and presumably better energy balance, had earlier CLA (P<0.01) and DAI1 (P<0.10). In addition, higher milk yield was associated with poorer ovulation detection rate and oestrus intensity (P<0.05). The study showed that at similar EBV level for milk solids, selection for increased milk fat and protein content resulted in improved cyclicity and similar oestrous expression and submission rates compared with selection for increased milk yield.

  • Ability of dairy cows to ensure pregnancy according to breed and Genetic Merit for production traits under contrasted pasture-based systems
    Journal of Dairy Science, 2017
    Co-Authors: Nicolas Bedere, Ségolène Colette, Catherine Disenhaus, Vincent Ducrocq, Luc Delaby
    Abstract:

    The present study aimed to assess and measure the effects of breed, Genetic Merit for production traits, and feeding systems (FS) on the ability of dairy cows to ensure pregnancy through its components (fertilization, embryonic losses, recalving). An experiment was conducted over 9 yr on Normande and Holstein cows assigned to contrasted FS. Diets were based on maize silage in winter and grazing plus concentrate in spring in the high FS group, and on grass silage in winter and grazing with no concentrate during spring in the low FS group. Within breeds, cows were classified into 2 groups with similar estimated breeding values (EBV) for milk solids: cows with high EBV for milk yield were included in a milk group and those with high EBV for fat and protein contents were included in a content group. Holstein cows produced more milk throughout lactation than Normande cows (the differential was greater in the high FS group, +2,294 kg, compared with +1,280 kg in the low FS group) and lost more body condition to nadir (the differential was greater in the high FS group, -1.00 point, compared with -0.80 point in the low FS group). Within breeds, milk solids production was similar between Genetic groups. Cows in the high FS group produced more milk (+2,495 kg for Holstein and +1,481 kg for Normande cws) and had a higher body condition score at nadir (+0.40 point for Holstein and +0.60 point for Normande) than cows in the low FS group. Holstein cows had a lower recalving rate than Normande cows (-19 percentage units). We found no effect of Genetic group and FS on fertility of Normande cows. However, according to FS, Holstein cows in the content group exhibited different fertility failure patterns. In the low FS group, Holstein cows in the content group had more nonfertilizations or early embryo mortality (+26 percentage units at first and second services) than Holstein cows in the milk group. In the high FS group, Holstein cows in the content group had a higher proportion of late embryo mortality than in the milk group (+10 percentage units at first and second services). We observed no effect of FS on recalving rate; however, indicators of energy balance (protein content or body condition score) were positively associated with successful conception and pregnancy. This suggested a link between Genetic Merit for fat and protein content and lower ability of dairy cows to ensure pregnancy because of more nonfertilizations and early or late embryo mortality.

  • Toward improved postpartum cyclicity of primiparous dairy cows: Effects of Genetic Merit for production traits under contrasting feeding systems
    Journal of Dairy Science, 2016
    Co-Authors: Nicolas Bedere, Ségolène Colette, Vincent Ducrocq, Luc Delaby, Catherine Disenhaus
    Abstract:

    Milk Genetic Merit is known to affect commencement of luteal activity (C-LA) in dairy cows. This effect is considered to be due to energy exported in milk production. The present study aimed to identify and quantify the effects of Genetic characteristics [breed and estimated breeding value (EBV) for milk yield and fat and protein contents] and feeding system on C-LA of primiparous cows. From 2006 to 2013, an experiment was conducted on 97 primiparous dairy (Holstein) and 97 primiparous dual-purpose (Normande) cows. Within breed, cows were classified into 2 groups: cows with high EBV for milk yield were included in a "milk group" and those with high EBV for fat and protein contents were included in a "content group." Within breed, exported energy in milk and body weight (BW) loss were similar for both Genetic groups. Two grazing-based strategies were used, a high feeding system (maize silage in winter and grazing plus concentrate) and a low feeding system (grass silage in winter and grazing with no concentrate). Interval from calving to C-LA was studied performing survival analyses. Milk progesterone profile, milk yield, and body condition were analyzed using χ2-test and analysis of covariance. Holstein cows produced more milk (+1,810 kg in the high feeding system and +1,120 kg in the low feeding system) and lost more BW from wk 1 to 14 of lactation (-1.4 kg/wk) than Normande cows, whereas Normande cows had earlier C-LA than Holstein cows. Within breed, cows in the content group had earlier C-LA (associated hazard ratio = 2.0) than cows in the milk group. Body weight at calving and loss from wk 1 to 14 of lactation tended to be associated with later C-LA. Cows in the high feeding system produced more milk (+2,040 kg for the Holstein cows and +1,350 kg for Normande cows) and lost less BW from wk 1 to 14 of lactation (+3.8 kg/wk) than cows in the low feeding system. No effect of feeding system or milk yield was observed on C-LA. Prolonged luteal phases were frequent (18% of cows) and were not associated with either breed or Genetic group. Ovarian cycles were longer for Holstein than for Normande cows (+1.7 d) because of a longer luteal phase and a longer interluteal interval. Results of the study could be useful to establish strategies to manage declining reproductive performances at Genetic and environmental levels. This study showed that cows with a Genetic predisposition to export milk energy through fat and protein contents had earlier C-LA than predisposed to export milk energy through yield.

  • effect of Genetic Merit and concentrate supplementation on grass intake and milk production with holstein friesian dairy cows
    Journal of Dairy Science, 2003
    Co-Authors: Luc Delaby, P Dillon, J Kennedy, Philippe Faverdin, G Stakelum, M Rath
    Abstract:

    Abstract A total of 48 high Genetic Merit (HM) and 48 medium Merit (MM) cows, each given a low (LC), medium (MC), or high (HC) level of concentrate supplementation, were used in a split-plot design experiment, which was run in three consecutive years, to evaluate animal production responses. Individual cow intakes were estimated twice each year while at pasture; measurement period 1 (MPI) was in May/June, and measurement period 2 (MP2) was in early September, corresponding on average to d 110 and 200 of lactation, respectively. In MP1, cows were offered 0 (LC), 3 (MC), and 6kg (HC), whereas in MP2 the levels were 0 (LC), 0 (MC), and 4kg (HC) of concentrate daily. Genotype had a significant effect on all milk production parameters in MP1 and MP2. The HM cows had the highest yield of milk, fat, protein, and lactose, whereas the MM cows had the highest milk fat, protein, and lactose concentrations. The HM cows had significantly higher grass dry matter intake (GDMI) estimates. In MP1, the average responses, per kg concentrate dry matter, was +1.10kg of milk, +0.038kg of protein, +0.032kg of fat. The corresponding values in MP2 were +0.94kg of milk, +0.037kg of protein, and +0.025kg of fat. The response to concentrate was linear and independent of preexperimental milk yield. In MP1, the partial regression coefficients relating daily GDMI to an increase in 1kg of preexperimental milk yield (PMY), preexperimental BW (PBW), and concentrate intake (CI) were 0.123, 0.006, and −0.54, respectively, whereas the corresponding values in MP2 were 0.190, 0.007, and −0.444, respectively. This study indicates that with high yielding dairy cows, on gras only GDMI of 17kg of supporting milk yield of 30-kg/d is achievable. In this scenario, concentrate supplementation will result in lower substitution rates, and higher milk yield response than previously published with lower yielding cows.

  • the influence of cow Genetic Merit for milk production on response to level of concentrate supplementation in a grass based system
    Animal Science, 2002
    Co-Authors: J Kennedy, Luc Delaby, P Dillon, F Buckley, Philippe Faverdin, M Rath
    Abstract:

    The objective of this study was to investigate if there is a genotype ✕ feeding system interaction for milk production in Holstein-Friesian dairy cows. For this purpose, 48 high Genetic Merit (HM) and 48 medium Genetic Merit (MM) dairy cows, were used in a two (genotypes) ✕ three (levels of concentrate feeding) randomized-block design experiment in three consecutive years. In year 1, all animals were in their first lactation, while in year 2 and year 3, 18 and 12 first lactation cows replaced animals culled at the end of the previous lactation. A total of 66 cows remained in the study in the same feeding system for the 3-year duration of the study. Concentrate feeding levels were 376, 810 and 1540 kg per cow per lactation; these were identified as the LC, MC and HC feeding systems respectively. There was a separate farmlet for each feeding system; farmlets were managed so that pre-grazing and post-grazing herbage height were similar for all three feeding systems. When compared on treatment means there was a significant genotype ✕ feeding system interaction for fat yield, while for mean solid-corrected milk yield the interaction was close to statistical significance (P = 0·07). However, regression coefficients of both milk and protein yield on pedigree index for milk and protein yield were significantly different between the LC and the HC. The interaction between feeding system and the regression of both on pre-experimental milk and protein yield were close to statistical significance (P = 0·08 and P = 0·09 respectively). Outputs of milk, fat, protein and lactose were greater for the HM than the MM cows. Feeding system had a significant effect on milk, fat, protein and lactose yields. There was a significant genotype ✕ feeding system interaction for body condition score (BCS) at the end of lactation; the MM cows had a higher rate of body tissue repletion than the HM cows especially in the HC system. The results suggest that there is a genotype ✕ concentrate feeding level interaction and that feeding systems developed in the past for animals of lower Genetic Merit may require adaptation if they are to be optimal for higher Genetic Merit animals.

M Rath - One of the best experts on this subject based on the ideXlab platform.

  • the effect of Genetic Merit for milk production and concentrate feeding level on the reproductive performance of holstein friesian cows in a grass based system
    Animal Science, 2003
    Co-Authors: J Kennedy, P Dillon, F Buckley, Kathleen Osullivan, M Rath
    Abstract:

    The objective of the study was to evaluate the effect on reproductive performance of varying level of concentrate supplementation with both high and medium Genetic Merit cows in a spring calving grass-based system of milk production. The effect of year, cow Genetic Merit for milk production and concentrate feeding level on milk production, body condition score, live weight, blood metabolites and dry-matter (DM) intake were studied. A repeated measures model with a factorial arrangement of Genetic Merit and concentrate feeding level was used to do this. Associations between these variables and pregnancy to first service (PREG1), pregnancy to first and second service (PREG12) and overall pregnancy (PREG) rates were assessed using logistic regressions for year 2. Cows were grouped into high (HM) and medium (MM) Genetic Merit based on their pedigree indices for milk production (PD milk). The HM cows had a PD milk of + 276 (s.d. 100) kg, while the MM cows had mean PD milk of + 81 (s.d. 95) kg. Within Genetic Merit groupings, cows were assigned to one of three concentrate feeding levels; low (LC), 376 kg; medium (MC), 810 kg; and high (HC), 1540 kg of concentrate per cow per lactation. In year 1, all 78 cows were second lactation animals, while in year 2, 71 cows (previously in year 1) were third lactation and 12 second lactation. All cows calved between February and April, and were presented for rebreeding from late April until late July each year. When treatment means were compared, genotype and concentrate feeding levels had no significant effects on reproductive performance while year was significant for most parameters. Comparing year 2 to year 1 pregnancy rate to first service (P 0•001; 37 v. 64%), pregnancy rate to first and second service (P < 0•05; 64 v. 81%), overall pregnancy rate (P < 0•05; 78 v. 92%) were lower. Also in year 2, cows had significantly higher milk yields at first insemination (36•9 v. 32•3 kg per cow per day), greater live-weight losses from calving to first insemination (-86 v. –53 kg per cow), lower live-weight gain in the 90 days after their first insemination (+ 24•6 v. + 34•2 kg per cow), higher DM intake (20•6 v. 17•3 kg DM per cow per day) and lower plasma glucose concentrations (3•18 v. 3•61 mmol/l) than in year 1. In year 2, there were significant negative associations between the likelihood of PREG12 and both PD milk and live-weight gain in the 90 days after first insemination. The results of this study indicate that continued selection for increased milk production, resulting in greater partitioning of energy to milk production rather than body reserves will reduce reproductive performance and offering higher levels of concentrate supplementation may not alleviate this problem.

  • effect of Genetic Merit and concentrate supplementation on grass intake and milk production with holstein friesian dairy cows
    Journal of Dairy Science, 2003
    Co-Authors: Luc Delaby, P Dillon, J Kennedy, Philippe Faverdin, G Stakelum, M Rath
    Abstract:

    Abstract A total of 48 high Genetic Merit (HM) and 48 medium Merit (MM) cows, each given a low (LC), medium (MC), or high (HC) level of concentrate supplementation, were used in a split-plot design experiment, which was run in three consecutive years, to evaluate animal production responses. Individual cow intakes were estimated twice each year while at pasture; measurement period 1 (MPI) was in May/June, and measurement period 2 (MP2) was in early September, corresponding on average to d 110 and 200 of lactation, respectively. In MP1, cows were offered 0 (LC), 3 (MC), and 6kg (HC), whereas in MP2 the levels were 0 (LC), 0 (MC), and 4kg (HC) of concentrate daily. Genotype had a significant effect on all milk production parameters in MP1 and MP2. The HM cows had the highest yield of milk, fat, protein, and lactose, whereas the MM cows had the highest milk fat, protein, and lactose concentrations. The HM cows had significantly higher grass dry matter intake (GDMI) estimates. In MP1, the average responses, per kg concentrate dry matter, was +1.10kg of milk, +0.038kg of protein, +0.032kg of fat. The corresponding values in MP2 were +0.94kg of milk, +0.037kg of protein, and +0.025kg of fat. The response to concentrate was linear and independent of preexperimental milk yield. In MP1, the partial regression coefficients relating daily GDMI to an increase in 1kg of preexperimental milk yield (PMY), preexperimental BW (PBW), and concentrate intake (CI) were 0.123, 0.006, and −0.54, respectively, whereas the corresponding values in MP2 were 0.190, 0.007, and −0.444, respectively. This study indicates that with high yielding dairy cows, on gras only GDMI of 17kg of supporting milk yield of 30-kg/d is achievable. In this scenario, concentrate supplementation will result in lower substitution rates, and higher milk yield response than previously published with lower yielding cows.

  • the influence of cow Genetic Merit for milk production on response to level of concentrate supplementation in a grass based system
    Animal Science, 2002
    Co-Authors: J Kennedy, Luc Delaby, P Dillon, F Buckley, Philippe Faverdin, M Rath
    Abstract:

    The objective of this study was to investigate if there is a genotype ✕ feeding system interaction for milk production in Holstein-Friesian dairy cows. For this purpose, 48 high Genetic Merit (HM) and 48 medium Genetic Merit (MM) dairy cows, were used in a two (genotypes) ✕ three (levels of concentrate feeding) randomized-block design experiment in three consecutive years. In year 1, all animals were in their first lactation, while in year 2 and year 3, 18 and 12 first lactation cows replaced animals culled at the end of the previous lactation. A total of 66 cows remained in the study in the same feeding system for the 3-year duration of the study. Concentrate feeding levels were 376, 810 and 1540 kg per cow per lactation; these were identified as the LC, MC and HC feeding systems respectively. There was a separate farmlet for each feeding system; farmlets were managed so that pre-grazing and post-grazing herbage height were similar for all three feeding systems. When compared on treatment means there was a significant genotype ✕ feeding system interaction for fat yield, while for mean solid-corrected milk yield the interaction was close to statistical significance (P = 0·07). However, regression coefficients of both milk and protein yield on pedigree index for milk and protein yield were significantly different between the LC and the HC. The interaction between feeding system and the regression of both on pre-experimental milk and protein yield were close to statistical significance (P = 0·08 and P = 0·09 respectively). Outputs of milk, fat, protein and lactose were greater for the HM than the MM cows. Feeding system had a significant effect on milk, fat, protein and lactose yields. There was a significant genotype ✕ feeding system interaction for body condition score (BCS) at the end of lactation; the MM cows had a higher rate of body tissue repletion than the HM cows especially in the HC system. The results suggest that there is a genotype ✕ concentrate feeding level interaction and that feeding systems developed in the past for animals of lower Genetic Merit may require adaptation if they are to be optimal for higher Genetic Merit animals.

  • Genetic Merit for milk production and reproductive success in dairy cows
    Animal Reproduction Science, 2001
    Co-Authors: S E M Snijders, D Ocallaghan, P Dillon, K J Ofarrell, M G Diskin, A R G Wylie, M Rath, M P Boland
    Abstract:

    Abstract The effect of Genetic Merit for milk production traits — fat, protein and milk yield — in dairy cows on milk production, body condition, blood metabolites, reproductive hormones, feed intake and reproductive performance was studied over a period of 2 years. Cows were grouped into two categories, based on calculated pedigree indices using multiple-trait across country evaluation (MACE). Cows of high Genetic Merit (HGM, n=48 in year 1 and n=46 in year 2) had a mean predicted difference ±standard deviation for milk production of 475±76 kg. The cows of medium Genetic Merit (MGM, n=48 in both years) had a mean predicted difference for milk production of 140±68 kg. The cows calved between January and April, and were offered grass silage ad libitum plus 9 kg concentrates per cow per day, irrespective Genetic Merit, from calving to turnout in March, when they were subjected to one of three grazing systems. Cows were available for rebreeding from late April until late July of each year. High Genetic Merit cows had higher milk production, incurred greater body condition loss between calving and first service and had lower plasma glucose and insulin-like growth factor-1 (IGF-1) concentrations than medium Genetic Merit cows. Furthermore, HGM cows had lower first and second service and overall conception rates, and required more services per conception than the MGM cows. Cows that did not conceive to first service were retrospectively compared to those that conceived to first service within each Genetic Merit group. There were no significant differences between the HGM cows that did not conceive to first service and those that conceived to this service in terms of milk production, body condition score change between calving and first service, feed intake at first service, or in plasma concentrations of glucose, non-esterified fatty acids (NEFA) or IGF-1. Medium Genetic Merit cows that did not conceive to first service lost more body condition between calving and first service than did those that conceived to this service. In the present study, HGM cows had higher milk production and reduced reproductive performance in comparison with MGM cows. However, reproductive performance was not associated with milk production, feed intake or plasma concentrations of glucose, NEFA or IGF-1 between calving and first service, since there were no significant differences in these variates between high or medium Genetic Merit cows that did not conceive to first service and those that conceived to this service. Therefore, these variates are unlikely to be useful predictors of reproductive performance, under the conditions of the present study.

  • the effects of cow Genetic Merit and feeding treatment on milk production herbage intake and grazing behaviour of dairy cows
    Irish Journal of Agricultural and Food Research, 2000
    Co-Authors: J M Oconnell, F Buckley, M Rath, P Dillon
    Abstract:

    The objective of the present study was to investigate the effects of cow Genetic Merit and grass-based feeding treatment on milk production, herbage intake and grazing behaviour of first lactation Holstein-Friesian dairy cows. A total of 48 high Genetic Merit cows (HG) and 48 medium Genetic Merit cows (MG) were assigned, within Merit group to three grass-based feeding treatments: 1) standard feeding treatment, 2) high concentrate and 3) high grass allowance. The HG cows had a higher milk yield (24.7 v. 21.2 kg/day; P < 0.001), fat yield (0.87 v. 0.82 kg/day; P < 0.05), protein yield (0.81 v. 0.73 kg/day; P < 0.001) and lactose yield (1.14 v. 1.00 kg/day; P < 0.001) than the MG cows. The milk of the HG cows had lower fat (35.6 v. 38.7 g/kg; P < 0.01), protein (33.2 v. 34.5 g/kg; P < 0.01) and lactose (46.4 v. 47.6 g/kg; P < 0.01) concentrations. The HG cows had a higher (P < 0.01) grass dry matter (DM) intake. Total grazing time was not affected by cow Genetic Merit but the HG cows had more (P < 0.10) grazing bouts of shorter (P < 0.05) duration. The HG cows also had higher (P < 0.001) biting rates and spent a greater (P < 0.01) proportion of time ruminating than the MG cows. Offering a higher level of concentrate (Treatment 2) significantly increased yield of milk (P < 0.001), fat (P < 0.05), protein (P < 0.001) and lactose (P < 0.001). The higher concentrate feeding treatment also resulted in a significantly (P < 0.001) higher lactose concentration with no effect on fat or protein concentrations. Allocating a higher allowance of grass (Treatment 3) had no effect on milk production except for lactose concentration which was higher (P < 0.05). Offering a higher level of concentrate reduced (P < 0.001) grass DM intake. Feeding treatments 2 and 3 both reduced (P < 0.05) the duration of grazing bouts and biting rate during the day.

Katrin Gegenfurtner - One of the best experts on this subject based on the ideXlab platform.

  • Genetic Merit for fertility alters the bovine uterine luminal fluid proteome†
    Biology of Reproduction, 2020
    Co-Authors: Katrin Gegenfurtner, Thomas Fröhlich, Florian Flenkenthaler, Miwako Kösters, Sébastien Fritz, Olivier Desnoes, Daniel Le Bourhis, Pascal Salvetti, Olivier Sandra, Gilles Charpigny
    Abstract:

    Over the last decades, fertility of dairy cows has declined due to selection strategies focusing on milk yield. To study the effect of Genetic Merit for fertility on the proteome of the bovine uterine luminal fluid, Holstein heifers with low- and two groups of heifers with high-fertility index (high-fertility Holstein and Montbeliarde) were investigated. To focus on the maternal effect, heifers from all groups were synchronized and received on Day 7 high-quality embryos. Uterine luminal fluid from Day 19 pregnant heifers was analyzed in a holistic proteomic approach using nano-LC-MS/MS analysis combined with a label-free quantification approach. In total, 1737 proteins were identified, of which 597 differed significantly in abundance between the three groups. The vast majority of proteome differences was found comparing both high-fertility groups to the low-fertility Holstein group, showing that the Genetic predisposition for fertility is prevalent regarding the uterine luminal fluid proteome. Evaluation of this dataset using bioinformatic tools revealed an assignment of higher abundant proteins in low-fertility Holstein to several metabolic processes, such as vitamin metabolic process, which comprises folate receptor alpha (FOLR1) and retinol-binding protein, indicating an involvement of disturbed metabolic processes in decreased fertility. Moreover, immune system-related proteins - lactotransferrin and chromogranin A - were enriched in low-fertility cows together with interferon tau 3 h and interferon tau-2. Our results indicate that the Genetic Merit for fertility leads to substantial quantitative differences at the level of proteins in uterine fluid of pregnant animals, thus altering the microenvironment for the early conceptus.

  • 67 influence of metabolic status and Genetic Merit for fertility on proteomic composition of bovine uterine luminal fluid
    Reproduction Fertility and Development, 2018
    Co-Authors: Katrin Gegenfurtner, P Lonergan, Thomas Fröhlich, Miwako Kösters, Sébastien Fritz, Pascal Salvetti, Evamaria O Riedel, Niamh Forde, E Wolf, G J Arnold
    Abstract:

    Intensive selection strategies focusing on increased milk yield over several decades has been associated with a decline in fertility in dairy cows. To study the effect of the Genetic Merit for fertility and the metabolic status of the female on the oocyte, early embryo and the maternal environment, 2 animal models were established. The Genetic Merit model involved Holstein heifers with a low (LFH) and high fertility (HFH) index and heifers from the Montbeliarde breed (MBD), known to have good reproductive performance. The metabolic model comprised samples from maiden heifers (MH), postpartum lactating cows (Lact), and non-lactating cows (dried off immediately after calving; Dry). A common pool of Day 7 embryos recovered from superovulated and artificially inseminated Holstein heifers were transferred into synchronised recipients (1/recipient) of the above-mentioned animal models and uterine lumen fluid (ULF) of confirmed pregnant animals was recovered on Day 19 post-oestrus. As communication between the conceptus and the uterine environment is crucial for the successful establishment of pregnancy, we analysed uterine luminal fluid of pregnant cows from both models using a holistic proteomic approach. Using nano-liquid chromatography-tandem mass spectrometry analysis combined with a label-free quantification approach, we analysed the uterine luminal fluid from the uterine horn ipsilateral to the corpus luteum (where the conceptus was located in all cases). A total of 2127 proteins were quantified in all samples of both models. Among this set of proteins, 458 were found to differ significantly (P-value < 0.05) in abundance between the groups of the Genetic model, and 141 were altered in abundance in the metabolic model. The majority of proteome differences in ULF samples was found comparing HFH to the LFH group (358) and between Dry and Lact cows (70) in the metabolic model. Evaluation of this dataset using bioinformatic tools comprising DAVID GO and gene set enrichment analysis revealed that the affected proteins were predominantly assigned to the terms “translation”, “monosaccharide metabolic process”, “enzyme inhibitor activity”, “lipid binding”, and “response to oxidative stress”. Our study revealed that metabolic status and Genetic Merit for fertility lead to quantitative molecular differences at the level of proteins in uterine fluid of pregnant animals, thus altering the microenvironment for the early conceptus. This research was funded by European Union Seventh Framework Programme FP7/2007-2013 under grant agreement no. 312097 (‘FECUND’).