Data/hora: 04/06/2024 00:13:34

Provedor de dados: 	19	
País: 	Japan	
Título: 	Effects of heat stress on production, somatic cell score and conception rate in Holsteins	
Autores: 	Hagiya, Koichi; Hayasaka, Kiyoshi; Yamazaki, Takeshi; Shirai, Tatsuo; Osawa, Takefumi; Terawaki, Yoshinori; Nagamine, Yoshitaka; Masuda, Yutaka; Suzuki, Mitsuyoshi.	
Data: 	2017	
Ano: 	2017	
Palavras-chave: 	Genetic correlation; Heat-stress; Holsteins; Temperature-humidity index (THI).	
Resumo: 	We examined the effects of heat stress (HS) on production traits, somatic cell score (SCS) and conception rate at first insemination (CR) in Holsteins in Japan. We used a total of 228242 records of milk, fat and protein yields, and SCS for the first three lactations, as well as of CR in heifers and in first- and second-lactation cows that had calved for the first time between 2000 and 2012. Records from 47 prefectural weather stations throughout Japan were used to calculate the temperature-humidity index (THI); areas were categorized into three regional groups: no HS (THI&lt;72), mild HS (72THI&lt;79), and moderate HS (THI79). Trait records from the three HS-region groups were treated as three different traits and trivariate animal models were used. The genetic correlations between milk yields from different HS groups were very high (0.91 to 0.99). Summer calving caused the greatest increase in SCS, and in the first and second lactations this increase became greater as THI increased. In cows, CR was affected by the interaction between HS group and insemination month: with summer and early autumn insemination, there was a reduction in CR, and it was much larger in the mild- and moderate-HS groups than in the no-HS group.	
Idioma: 	Inglês	
Identificador: 	http://ir.obihiro.ac.jp/dspace/handle/10322/4575

info:doi/10.1111/asj.12617	
Editor: 	Wiley-Blackwell	
Fonte: 	This is the peer reviewed version of the following article: Animal Science Journal: 88(1); JAN 2017; 3-10, which has been published in final form at http://doi.org/10.1111/asj.12617. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.