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도창희(Chang Hee Do),조재성(Jae Sung Cho),조광현(Kwang Hyun Cho),양보석(Boh Suk Yang),윤호백(Ho Baek Yun),이지수(Ji Su Lee) 충남대학교 농업과학연구소 2015 농업과학연구 Vol.42 No.3
Records of 490,767 cows collected from 1990 to 2012 by dairy herd milk test of National Agriculture Cooperative Federation The pedigree of dairy cattle were provided by Korea Animal Improvement Association. The data were used to analyze the longevity of dairy cows with the life traits such as days in milk, number of lactation, productive life, and life span. The data were also used to investigate genetic relationship of these longevity traits with profitability of dairy cows, including heritability and genetic correlation. The profitability was calculated with simulation of milk income and production costs for individual cows. Days in milk among the traits had ?0.287, -0.572 and ?0.536 of genetic correlation with number of lactations, productive life and lifespan, respectively. The heritabilities of life span, number of lactations, productive life, and days in milk were found to be 0.045, 0.047, 0.059 and 0.081, respectively. Genetic correlations of profit with productive life, number of lactations, and days in milk were identified as 0.072, 0.080, 0.098 and 0.101. These results suggested that days in milk was most desirable traits to represent longevity of Holstein dairy cattle. In general, since longevity and profitability were close genetic relationship each other, genetic improvement of longevity is necessary for better profitable cows.
유전 및 육종 : 국내 Holstein종 젖소의 생산수준이 젖소의 수익형질에 미치는 효과
도창희 ( Chang Hee Do ),박수훈 ( Su Hun Park ),조광현 ( Kwang Hyun Cho ),최연호 ( Yun Ho Choi ),최태정 ( Tae Jeong Choi ),박병호 ( Byung Ho Park ),윤호백 ( Ho Baek Yun ),이동희 ( Dong Hee Lee ) 한국동물자원과학회(구 한국축산학회) 2013 한국축산학회지 Vol.55 No.5
Data including 1,372,050 milk records pertaining to 438,019 cows from 1983 to 2011 collected during performance tests conducted by the National Livestock Cooperative Dairy Improvement Center were used to calculate milk income and profit of individuals and investigate the effects of production levels of early lactation(parity 1 and 2, respectively). Individuals with a moderate level of early lactation stayed longer in herds. Among parity 1, the 9,000kg or higher group had a lower mean number of lactations than the overall mean of 3.13. The 7,000kg or lower and 10,000kg or higher groups had lower mean life time milking days than the overall mean of 1,076.8 days. Standard deviations of lifetime traits tended to decrease as production levels increased. For parity 2, the 11,000kg or higher group had a lower mean number of lactation than the overall mean of 3.43. The lifetime milking days was highest in the 12,000kg group(1,212.0 days), and generally smaller in the lower groups. Profit increased as the production level of groups increased for both parity 1 and 2. In groups with low production levels, profit of parity 1 was higher than that of parity 2, while the reverse was true in groups with high production levels. These results suggest that individuals in the low production groups had a greater likelihood to be culled due to reproductive or other problems. Furthermore, the accuracy of the prediction of lifetime profit of individuals with a milk yield of 305 days seems to be higher for parity 2 than parity 1; therefore, it is desirable to predict lifetime profit using the 305d milk yield of parity 2. In conclusion, breeding goals are based on many factors in functions for the estimation of profit; however, production levels during early lactation(parity 1 and 2) can be used as indicators of profit to extend profitability.