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| Hagiya, Koichi; Hayasaka, Kiyoshi; Yamazaki, Takeshi; Shirai, Tatsuo; Osawa, Takefumi; Terawaki, Yoshinori; Nagamine, Yoshitaka; Masuda, Yutaka; Suzuki, Mitsuyoshi. |
| 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<72), mild HS (72THI<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... |
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Palavras-chave: Genetic correlation; Heat-stress; Holsteins; Temperature-humidity index (THI). |
| Ano: 2017 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/4575 |
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