Author
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Cole, John |
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Submitted to: AIPL Research Reports
Publication Type: Government Publication Publication Acceptance Date: 12/22/2006 Publication Date: 12/26/2006 Citation: Cole, J.B. 2006. Genetic evaluation of stillbirth. AIPL Research Report. SB1 (8-06). Interpretive Summary: A new stillbirth (SB) evaluation has been developed for Holstein bulls, and will be available beginning in August 2006. The data set includes 6 million stillbirth records from calves born since 1980. The genetic analysis includes effects for herd-year, year-season, parity-gender, sire birth year, maternal grandsire (MGS) birth year, sire, and MGS. Service sire SB (SSB) measures the effect of the calf itself on stillbirth. Daughter SB (DSB) measures the effect of a particular cow (daughter) on stillbirths. The SB test run included 44,290 AI bulls that either were the service sire for a cow with a calving record (for SSB) or had a daughter with a calving record (for DSB). The SB evaluations are expressed as percent stillbirths (%SB), where stillbirth is defined as a calf born dead or that dies within 48 hours of birth. Genetic bases for SSB and DSB were both set to 8%. Heritabilities of SSB and DSB are 3.0% and 6.5, respectively. Sire and daughter SB will be included in the August 2006 revision of Lifetime Net Merit (NM$). The four calving traits (SSB, DSB, and sire and daughter CE) will receive a total of 6% of the weight in NM$. Technical Abstract: A new stillbirth (SB) evaluation has been developed for Holstein bulls, and will be available beginning in August 2006. The data set includes 6 million stillbirth records from calves born since 1980. The genetic analysis includes effects for herd-year, year-season, parity-gender, sire birth year, maternal grandsire (MGS) birth year, sire, and MGS. Service sire SB (SSB) measures the effect of the calf itself on stillbirth. Daughter SB (DSB) measures the effect of a particular cow (daughter) on stillbirths. The SB test run included 44,290 AI bulls that either were the service sire for a cow with a calving record (for SSB) or had a daughter with a calving record (for DSB). The SB evaluations are expressed as percent stillbirths (%SB), where stillbirth is defined as a calf born dead or that dies within 48 hours of birth. Genetic bases for SSB and DSB were both set to 8%. Heritabilities of SSB and DSB are 3.0% and 6.5, respectively. Sire and daughter SB will be included in the August 2006 revision of Lifetime Net Merit (NM$). The four calving traits (SSB, DSB, and sire and daughter CE) will receive a total of 6% of the weight in NM$. |
