Тваринництво та технології харчових продуктів (Dec 2020)
THE RELATIONSHIP BETWEEN GROWTH RATES OF KYIV FACTORY TYPE UKRAINIAN BLACK-AND-WHITE DAIRY BREED HEIFERS AND COWS LIFELONG PRODUCTIVITY
Abstract
The studied of Kyiv factory type Ukrainian Black-and-White dairy cows productivity depending on heifers average daily gain. The studied of 1071 animals lifelong use data. Cattle was divide into 5 groups according to the values of average daily gains at the age of 0-3; 3-6; 6-12 and 12-15 months. Animals distributed on the standard deviation from average daily gain of the herd. In animals included in the groups studied the productivity of the first lactation and the period of productive use. It found that increase the heifer’s growth rate leads to decrease in the age of the first calving. The age of the first calving is most affect by the growth rate up to 3 months of age. Preservation of the first calving cows increases when the growth rate of heifers is slightly higher than the average herd. The highest survival of the first calving cows (93.8 %) obtained providing growing heifers aged 3-6 months with increments of 658-853 g. The highest milk yields during the first and highest lactation were obtain by growing heifers aged 6-12 months with an average daily gain over 710 g. Animals with the highest growth rate at other ages had a lactation graph with several peaks, which indicates their increased sensitivity to changes in conditions of use. The bath-shaped udder founded are more common in slow-growing animals from birth to 12 months. The increase in average daily gain led to an increase in the proportion of cows with rounded and cup-shaped udders. The not installed relationship between the average daily gain of heifers and the duration of the open data period and the period between calving. These traits are more relate to the milk production of cows than to the growth of heifers. The greatest duration of lifetime use, milk yield and number of calves during life were at the growth rate of heifers from birth to 12 months at the level of + 0.5σ… + 1.5σ to the average for the herd. A further increase in the growth rate during these periods led to a decrease in the duration of productive use by 0.4… 1.1 years and a lack of 0.4… 0.9 calving. Animals that at the age of 12-15 months had a growth rate at the level of the average herd with deviations within ± 0.5σ were marked by a long productive period. Studies prove the possibility of increasing the lifelong productivity of livestock by heifer’s selection at a growth rate from birth to 15 months
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