806
Genetic Analysis of Reproductive Traits, Milk Yield, and Persistency during the First 3 Lactations of Holstein cows

Tuesday, August 19, 2014
Posters (The Westin Bayshore)
Takeshi Yamazaki , NARO Hokkaido Agricultural Research Center, Sapporo, Hokkaido, Japan
Koichi Hagiya , NARO Hokkaido Agricultural Research Center, Sapporo, Hokkaido, Japan
Hisato Takeda , NARO Institute of Livestock and Grassland Science, Tsukuba, Japan
Shigeki Yamaguchi , Livestock Improvement Association of Japan, Tokyo, Japan
Takefumi Osawa , National Livestock Breeding Center, Fukushima, Japan
Yoshitaka Nagamine , Nihon University, Fujisawa, Japan
Abstract Text: The genetic correlations between reproductive traits in cows, 305-day milk yield, and persistency were estimated by using the first-, second-, and third-lactation records, which represented 476,284; 380,474; and 267,344 Japanese Holstein cows, respectively. Reproductive traits evaluated were days from calving to first insemination (DCF), conception rate for first insemination (CR), number of inseminations (NI), and days open. Persistency was defined as the difference between milk yields at 240 and 60 days in milk. The genetic correlation estimates within the first lactation were similar to those of the other lactations. The genetic correlations among reproductive traits were fairly strong, but those of DCF with CR and NI were relatively weak. Antagonistic genetic correlations, which ranged from 0.17 to 0.43 in absolute values, between reproductive traits and 305-day milk yield or persistency were revealed.

Keywords:

dairy cattle

persistency

reproductive traits

See more of: Posters: Dairy Cattle Breeding (Group 1)
See more of: Species Breeding: Dairy cattle
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