Factors associated with 56-day non-return rate in dairy cattle

Pesquisa Agropecuária Brasileira

Ramiro Fouz²  Fernando Gandoy²  María Luisa Sanjuán¹  Eduardo Yus¹  Francisco Javier Diéguez¹ 

[1] ,Africor Lugo Ronda de Fingoi Lugo,Spain

关键词: dairy cattle;    logistic models;    reproductive performance;    sire influence;    bovinos leiteiros;    modelos logísticos;    desempenho reprodutivo;    efeito paterno;   

DOI  :  10.1590/S0100-204X2011000600011

来源: SciELO

【 摘 要 】

The objective of this work was to identify factors associated with the 56-day non-return rate (56-NRR) in dairy herds in the Galician region, Spain, and to estimate it for individual Holstein bulls. The experiment was carried out in herds originated from North-West Spain, from September 2008 to August 2009. Data of the 76,440 first inseminations performed during this period were gathered. Candidate factors were tested for their association with the 56-NRR by using a logistic model (binomial). Afterwards, 37 sires with a minimum of 150 first performed inseminations were individually evaluated. Logistic models were also estimated for each bull, and predicted individual 56-NRR rate values were calculated as a solution for the model parameters. Logistic regression found four major factors associated with 56-NRR in lactating cows: age at insemination, days from calving to insemination, milk production level at the time of insemination, and herd size. First-service conception rate, when a particular sire was used, was higher for heifers (0.71) than for lactating cows (0.52). Non-return rates were highly variable among bulls. Asignificant part of the herd-level variation of 56-NRR of Holstein cattle seems attributable to the service sire. High correlation level between observed and predicted 56-NRR was found.

【 授权许可】

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