Some Production Traits of Holstein Cows at a State Farm in Middle Anatolian Conditions
2 Ankara Üniversitesi, Veteriner Fakültesi, Zootekni Anabilim Dalı, ANKARA - This study was carried out at Koças State Farm to investigate the effect of season, calving age, year and number of lactation on milk yield and reproductive traits of 275 Holstein cattles at the period of 1994-2000 and survival rates of calves in the period of 1996-2001 in Middle Anatolian conditions. Environmental factors were analysed by Least Squares Method.
According to the results, least squares mean of 305 day milk yield was 6400.0 kg, lactation length was 297.0 days and dry period was 74.0 days.
Among the reproductive traits of first conseption and first calving ages were found 542.3 days and 830.6 days respectively. While the effects of seasons on both traits were found to be insignificant, the factor of years had significant effect on the age of first conseption and first calving ages (P<0,001).
Least squares mean of service period was 109.7 days and were ranged from 94.9 to 121.5 days among lactation groups. The lactation numbers and calving season were found to be effective on service period (P<0,05). Least squares mean of calving interval was estimated 389.3 days.
The number of inseminations per conseption were ranged from 1.61 to 1.81; 1.21 to 1.91; 1.34 to 2.31 and 1.20 to 2.26 in season, year, lactation number and age of dam groups, respectively. The differences among all groups were found statistically significant (P<0,05, P<0,001).
Least squares mean of gestation length was 277.0 days. Only lactation number and the age of dam were found to be statistically significant on the gestation length ( P<0,001 and P<0,05). Gestation length was increased by the age and lactation number.
Conseption, calving, twinning, abortion and stillbirths rates were found 96.4, 94.5, 4.2, 1.9 and 4.1%, respectively. Conseption and calving rates among the calving season groups were found statistically significant (P<0,001, P<0,05). The lowest conseption and calving rate were obtained in spring group (92,36 and 91.40 %).
The general survival rates of 30, 90 and 180th days were detected 94.4; 92.4 and 92.1%, respectively. It was found that calving year and season effected the 30, 90 and 180th days survival rates, statistically significant (P<0,05; P<0,01; P<0,001). The effects of the sex of calf and the age of dam were found to be statistically insignificant.
According to the results, milk yield and lactation length of a Holstein herd in the Middle Anatolian conditions is ratherly good for Turkey conditions. But there is some problems on the reproductive traits and survival rates. Koças State Farm conditions is suitable to development for milk yield, reproductive traits and survival rates for this herd. For this reason some precautions must be taken in the management.
Keywords : Holstein, milk yield, fertility, survival rate, environmental factors