Data/hora: 05/06/2024 07:39:55

Provedor de dados: 	86	
País: 	Brazil	
Título: 	Factors associated with 56-day non-return rate in dairy cattle	
Autores: 	Fouz,Ramiro; Gandoy,Fernando; Sanjuán,María Luisa; Yus,Eduardo; Diéguez,Francisco Javier.	
Data: 	2011-06-01	
Ano: 	2011	
Palavras-chave: 	Dairy cattle; Logistic models; Reproductive performance; Sire influence.	
Resumo: 	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.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2011000600011	
Editor: 	Embrapa Secretaria de Pesquisa e Desenvolvimento

Pesquisa Agropecuária Brasileira	
Relação: 	10.1590/S0100-204X2011000600011	
Formato: 	text/html	
Fonte: 	Pesquisa Agropecuária Brasileira  v.46 n.6 2011	
Fonte: 	info:eu-repo/semantics/openAccess