Lactation Records Adjusted for Days Open in Sire Evaluation
نویسندگان
چکیده
منابع مشابه
Use of early lactation days open records for genetic evaluation of cow fertility.
National genetic evaluations for cow fertility were introduced by the USDA in February, 2003. These evaluations, reported as daughter pregnancy rate, are based on days open. One requirement of the evaluation system is that lactations be at least 250 d in milk (DIM) to be included for analysis. The objective of this research was to develop a predictor of days open, usable in genetic evaluation, ...
متن کاملEffects of twinning on lactation and days open in Holsteins.
Effects of twinning on lactation and days open in Holsteins were studied from calving records compiled by member surveys of Eastern Artificial Insemination Cooperative. Records of cows with 305-day mature-equivalent records from the Northeast Dairy Records Processing Laboratory were grouped according to whether the twin calving was associated with dystocia. Records of each cow that had a twin c...
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The standard of comparison for dairy production records is the 305-day lactation, and much research has been directed to estimating 305-day milk and fat records from incomplete or in-progress records. This study was to determine the effect of several methods of extending incomplete records on sire evaluation. Complete 305-day milk and fat records of first lactations of 73,724 daughters of 1,362...
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متن کاملSire Evaluation for Milking Duration
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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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 1973
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(73)85226-9