Progress 08/01/08 to 12/31/10
Outputs
Progress Report Objectives (from AD-416) This study will utilize genotypes from the Illumina Bovine SNP50 chip on the foundation sires used in the Virginia Tech � Univ. of Kentucky � NC State Univ. crossbreeding project. The purpose of this project is to evaluate the use of genome scans of Holstein and Jersey sires used in a designed crossbreeding study for prediction of production and fitness traits in purebred and crossbred progeny. A further objective is to compare health, fitness, and fertility traits on purebred Holsteins, Jerseys, and reciprocal crosses of those two breeds in the same experiment and to estimate heterosis for these and other traits in Holstein-Jersey crosses. Approach (from AD-416) Phenotypes will be collected from animals in three crossbreeding projects. Phenotypes available include disease incidence, reproductive and production data and feed intake data. This crossbreeding experiment utilizes a diallele scheme whereby both males and females of both breeds are mated in purebred and crossbred combinations. The design will enable us to examine the accuracy of genomic prediction of transmitting ability in purebred and crossbred progeny managed contemporaneously. The plan allows estimates of heterosis with precision not possible from field data. Phenotypes will be collected under management conditions that are nearly equal across breed groups. Data analysis to determine utility of genomic information for prediction of daughter performance will be based similar to those outlined by VanRaden (Interbull Bull. 37:33�36. 2007). Breed group comparisons will be based on mixed models with genetic relationships considered. Heterosis will be measured for the various traits in two ways: as a percentage through the ratio of mean crossbred performance to purebred midpoint; and based on the linear regression of phenotype on percent of heterozygous gene combinations in the animal expressing the trait. In this approach, additive and maternal effects of Holstein genes will be contrasted to Jersey genes in the same model to eliminate those genetic effects from heterosis. Prediction of phenotypes by estimates of transmitting ability of sires (and dams) of cows has been widely used to evaluate utility of estimates of genetic merit. This study will use published estimates of genetic merit as well as research estimates of transmitting ability including genome data to predict performance of purebred and crossbred Holstein/Jersey cows. The utility of genome data for prediction of performance of crossbred animals is unknown. The structure of the diallele cross used in this experiment is ideally suited to address this question. These data will provide a unique test of the ability to predict the performance of crossbred animals and produce information for educational programs. A variety of unique phenotypes may become available during the time covered by this agreement. For instance, blood samples are drawn from animals in the Virginia Tech herd (approximately 40 cows of each breed group) once a week for the first 10 weeks of first or second lactation. These blood samples are being used to determine progesterone levels as well as other blood parameters related to health events such as sub- clinical ketosis. Progesterone profiles can be used as an additional measure of reproductive fitness, as interval to first detection of progesterone indicates the rapidity with which cows return to normal reproductive cycles. Detection of ketone bodies in the blood following calving may prove useful to identifying cows more able to recover from the rigors of calving and cow movement to consume adequate nutrients for high production. Breed group differences will help researchers make good recommendations to dairy producers regarding value of purebreds versus crossbreds. The project was related to in-house objectives 1 (collect genotypes and new phenotypes to improve accuracy and comprehensiveness of the national dairy database), 2 (characterize phenotypic measures of dairy practices and provide the industry with information for determining impact of herd management decisions on profitability), and 3 (improve accuracy of prediction of economically important traits currently evaluated, determine merit and potential for developing genetic predictions for new traits, and investigate methods to incorporate high-density genomic data). Calvings from the Holstein-Jersey crossbreeding trial at Virginia Tech, University of Kentucky, and North Carolina State University were analyzed for breed comparisons, heterosis, additive and maternal effects for dystocia, stillbirth, gestation length and birth weight. Heifers born at the Virginia Tech dairy also were used to investigate first-lactation feed intakes, body weights, milk weights, fertility, and metabolic diseases. Energy balance curves and components of energy balance curves were derived for all cows. Incidences of metabolic diseases during early lactation were used to investigate breed differences for metabolic diseases and their relationship to energy balance and related traits. In addition, three methods for multibreed genomic evaluation were investigated and compared to results within breed. The research resulted in three peer-reviewed scientific publications. Monitoring activities for the project included consultation with the Cooperator's principal investigator at national meetings and direct interaction with the Cooperator�s postdoctoral research associate as well as e-mail and phone calls.
Impacts
(N/A)
Publications
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Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) This study will utilize genotypes from the Illumina Bovine SNP50 chip on the foundation sires used in the Virginia Tech � Univ. of Kentucky � NC State Univ. crossbreeding project. The purpose of this project is to evaluate the use of genome scans of Holstein and Jersey sires used in a designed crossbreeding study for prediction of production and fitness traits in purebred and crossbred progeny. A further objective is to compare health, fitness, and fertility traits on purebred Holsteins, Jerseys, and reciprocal crosses of those two breeds in the same experiment and to estimate heterosis for these and other traits in Holstein-Jersey crosses. Approach (from AD-416) Phenotypes will be collected from animals in three crossbreeding projects. Phenotypes available include disease incidence, reproductive and production data and feed intake data. This crossbreeding experiment utilizes a diallele scheme whereby both males and females of both breeds are mated in purebred and crossbred combinations. The design will enable us to examine the accuracy of genomic prediction of transmitting ability in purebred and crossbred progeny managed contemporaneously. The plan allows estimates of heterosis with precision not possible from field data. Phenotypes will be collected under management conditions that are nearly equal across breed groups. Data analysis to determine utility of genomic information for prediction of daughter performance will be based similar to those outlined by VanRaden (Interbull Bull. 37:33�36. 2007). Breed group comparisons will be based on mixed models with genetic relationships considered. Heterosis will be measured for the various traits in two ways: as a percentage through the ratio of mean crossbred performance to purebred midpoint; and based on the linear regression of phenotype on percent of heterozygous gene combinations in the animal expressing the trait. In this approach, additive and maternal effects of Holstein genes will be contrasted to Jersey genes in the same model to eliminate those genetic effects from heterosis. Prediction of phenotypes by estimates of transmitting ability of sires (and dams) of cows has been widely used to evaluate utility of estimates of genetic merit. This study will use published estimates of genetic merit as well as research estimates of transmitting ability including genome data to predict performance of purebred and crossbred Holstein/Jersey cows. The utility of genome data for prediction of performance of crossbred animals is unknown. The structure of the diallele cross used in this experiment is ideally suited to address this question. These data will provide a unique test of the ability to predict the performance of crossbred animals and produce information for educational programs. A variety of unique phenotypes may become available during the time covered by this agreement. For instance, blood samples are drawn from animals in the Virginia Tech herd (approximately 40 cows of each breed group) once a week for the first 10 weeks of first or second lactation. These blood samples are being used to determine progesterone levels as well as other blood parameters related to health events such as sub- clinical ketosis. Progesterone profiles can be used as an additional measure of reproductive fitness, as interval to first detection of progesterone indicates the rapidity with which cows return to normal reproductive cycles. Detection of ketone bodies in the blood following calving may prove useful to identifying cows more able to recover from the rigors of calving and cow movement to consume adequate nutrients for high production. Breed group differences will help researchers make good recommendations to dairy producers regarding value of purebreds versus crossbreds. The project is related to in-house objectives 1 (collect genotypes and new phenotypes to improve accuracy and comprehensiveness of the national dairy database), 2 (characterize phenotypic measures of dairy practices and provide the industry with information for determining impact of herd management decisions on profitability), and 3 (improve accuracy of prediction of economically important traits currently evaluated, determine merit and potential for developing genetic predictions for new traits, and investigate methods to incorporate high-density genomic data). Energy balance and incidence of disease (displaced abomasum, ketosis, mastitis, and metritis) early in lactation (first 15 weeks) were investigated for Holsteins, Jerseys, and Holstein-Jersey crossbreds. Probability of an incidence of mastitis was lower for Holsteins than for crossbreds or Jerseys, but crossbreds were less likely than Holsteins to have an occurrence of metritis. No breed differences were found for ketosis, displaced abomasum, or pregnancy at 150 days in milk. Cows that had an incidence of ketosis had a more negative energy balance at week 15 in lactation, but energy balance was not affected by other health disorders. Energy intake was lower for cows with an incidence of displaced abomasums or mastitis. Energy balance at 15 weeks did not affect incidence of mastitis, metritis, or displaced abomasums, but cows with less severe negative energy balance tended to have higher odds of becoming pregnant by 150 days in milk. An incidence of mastitis reduced intakes, milk production, and feed efficiency but did not affect energy balance because declines in feed intake and milk production were enough to compensate. Differences in reproductive performance and nonesterified fatty acid concentration between Holsteins, Jerseys, and crossbreds also were examined. Days open were fewer for crossbreds sired by Jerseys. Services per conception were higher for Holsteins. Nonesterified fatty acid concentration was affected more by parity, season, week postpartum, and interaction between breed and parity. Two scientific papers and a scientific abstract were published in the Journal of Dairy Science; another scientific paper was submitted to the Journal of Dairy Science in May 2010. A postdoctoral research associate was hired by the Cooperator and was located at the Animal Improvement Programs Laboratory through May 2010 to allow frequent, direct interaction with Laboratory researchers. Monitoring activities for the project also included consultation with the Cooperator's principal investigator at a national meeting as well as e- mail and phone calls.
Impacts
(N/A)
Publications
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Progress 10/01/08 to 09/30/09
Outputs
Progress Report Objectives (from AD-416) This study will utilize genotypes from the Illumina Bovine SNP50 chip on the foundation sires used in the Virginia Tech � Univ. of Kentucky � NC State Univ. crossbreeding project. The purpose of this project is to evaluate the use of genome scans of Holstein and Jersey sires used in a designed crossbreeding study for prediction of production and fitness traits in purebred and crossbred progeny. A further objective is to compare health, fitness, and fertility traits on purebred Holsteins, Jerseys, and reciprocal crosses of those two breeds in the same experiment and to estimate heterosis for these and other traits in Holstein-Jersey crosses. Approach (from AD-416) Phenotypes will be collected from animals in three crossbreeding projects. Phenotypes available include disease incidence, reproductive and production data and feed intake data. This crossbreeding experiment utilizes a diallele scheme whereby both males and females of both breeds are mated in purebred and crossbred combinations. The design will enable us to examine the accuracy of genomic prediction of transmitting ability in purebred and crossbred progeny managed contemporaneously. The plan allows estimates of heterosis with precision not possible from field data. Phenotypes will be collected under management conditions that are nearly equal across breed groups. Data analysis to determine utility of genomic information for prediction of daughter performance will be based similar to those outlined by VanRaden (Interbull Bull. 37:33�36. 2007). Breed group comparisons will be based on mixed models with genetic relationships considered. Heterosis will be measured for the various traits in two ways: as a percentage through the ratio of mean crossbred performance to purebred midpoint; and based on the linear regression of phenotype on percent of heterozygous gene combinations in the animal expressing the trait. In this approach, additive and maternal effects of Holstein genes will be contrasted to Jersey genes in the same model to eliminate those genetic effects from heterosis. Prediction of phenotypes by estimates of transmitting ability of sires (and dams) of cows has been widely used to evaluate utility of estimates of genetic merit. This study will use published estimates of genetic merit as well as research estimates of transmitting ability including genome data to predict performance of purebred and crossbred Holstein/Jersey cows. The utility of genome data for prediction of performance of crossbred animals is unknown. The structure of the diallele cross used in this experiment is ideally suited to address this question. These data will provide a unique test of the ability to predict the performance of crossbred animals and produce information for educational programs. A variety of unique phenotypes may become available during the time covered by this agreement. For instance, blood samples are drawn from animals in the Virginia Tech herd (approximately 40 cows of each breed group) once a week for the first 10 weeks of first or second lactation. These blood samples are being used to determine progesterone levels as well as other blood parameters related to health events such as sub- clinical ketosis. Progesterone profiles can be used as an additional measure of reproductive fitness, as interval to first detection of progesterone indicates the rapidity with which cows return to normal reproductive cycles. Detection of ketone bodies in the blood following calving may prove useful to identifying cows more able to recover from the rigors of calving and cow movement to consume adequate nutrients for high production. Breed group differences will help researchers make good recommendations to dairy producers regarding value of purebreds versus crossbreds. Significant Activities that Support Special Target Populations The project is related to in-house objectives 1 (collect genotypes and new phenotypes to improve accuracy and comprehensiveness of the national dairy database), 2 (characterize phenotypic measures of dairy practices and provide the industry with information for determining impact of herd management decisions on profitability), and 3 (improve accuracy of prediction of economically important traits currently evaluated, determine merit and potential for developing genetic predictions for new traits, and investigate methods to incorporate high-density genomic data). Net energy balance on a lactation basis was estimated for 1st-lactation Holsteins, Jerseys, and reciprocal crosses. No differences were found for energy analyses of reciprocal crossbreds. Holsteins consumed more energy than Holstein-Jersey crossbreds and Jerseys. No breed group differences were found for total energy required for pregnancy, percentage of energy used for pregnancy and growth, week of return to positive energy balance, or positive cumulative energy balance. Jersey-Holstein crossbreds used less energy (26%) for maintenance than did Holsteins (28%). Effect of breed, profile of plasma progesterone, season (cool or hot), and interaction of breed and season on subsequent reproductive performance was evaluated. Days open were affected by breed, profile, and breed- season interaction: 153 days for Holsteins, around 130 days for crossbreds, and 140 days for Jerseys; cows with a short profile had 33 to 60 fewer days open. Slope of change in progesterone prior to 30 days postpartum also was affected by breed, profile, and breed-season interaction: 0.20 for Holsteins, 0.16 for crossbreds, and 0.23 for Jerseys; cows with a delayed profile had a slope of 0.002. Jersey slope was greater in summer and lower in winter than for other breed groups. Number of services per conception was affected by breed, season, and breed-season interaction: 2.3 for Holsteins, 1.9 to 2.0 for crossbreds, and 2.1 for Jerseys; services per conception were greater for the cool (2. 3) than hot season (1.9) except for Holstein-Jersey crossbreds. Effect of breed group on birth weight, gestation length, dystocia, and stillbirth were analyzed. Gestation length was not affected by breed group. Holsteins weighed more at birth than crossbreds, which weighed more than Jerseys. Dystocia was more likely for Holstein- than Jersey-sired calves. Stillbirth was more likely for Holstein- than Jersey-sired crossbred calves. Two presentations (1 oral, 1 poster) were made at the 2009 meeting of the Federation of Animal Science Societies; 2 abstracts were published in the meeting proceedings. A scientific paper was submitted to the Journal of Dairy Science. Funding for the project was increased to allow Cooperator recruitment of a high-quality postdoctoral candidate, who has an office at the Animal Improvement Programs Laboratory (June through September) to allow frequent, direct interaction with Laboratory researchers. Monitoring activities for the project also included consultation with the Cooperator's principal investigator at 4 national meetings as well as e-mail and phone calls.
Impacts
(N/A)
Publications
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