Bias of Sire Evaluations for Natural Service Sires and Age of Sire
نویسندگان
چکیده
منابع مشابه
Evaluations for service-sire conception rate for heifer and cow inseminations with conventional and sexed semen.
Service-sire conception rate (SCR), a phenotypic fertility evaluation based on conventional (nonsexed) inseminations from parities 1 through 5, was implemented for the United States in August 2008. The SCR model contains the categorical fixed effects of parity for lactations 1 to 5; state-year-month of insemination group; 6 standardized milk yield groups; service number for inseminations 1 to 7...
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The purpose of this research was to determine which (available) nuisance variables should be included in a model for phenotypic evaluation of US service sire conception rate (CR), based on field data. Alternative models were compared by splitting data into records for estimation and set-aside records, computing predictions using the estimation data, and then comparing predictions to bulls' aver...
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ACKNOWLEDGMENTS This project would not have been possible without the help of several individuals within the dairy industry. My advisor, Dr. Stan Henderson, provided the opportunity to research this project. Dr. Henderson guided me throughout the project and assisted in obtaining these data. Dr. Henderson also assisted in compiling these data and developing the manuscript. Without the help of D...
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Procedures for selecting sires are compared in terms of making maximum genetic progress in economic lnerit. A quadratic index, a simplified form of the quadratic index and a linear index to evaluate economic merit, and a restricted index to improve milk as much as possible while holding milk fat percentage constant, all result in nearly equal expected genetic progress in economic merit. Selecti...
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When linear programming is used to rank sires on daughter profits, coefficients of input are required for representative daughters of each sire. Within herdyear-season regressions of daughter's actual 305-day milk, fat percent, days open, 2-min milk yield adjusted for total yield, total milking time, and body weight at birth and first calving on sire's proofs for production, conformation, milki...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 1976
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(76)84492-x