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.

The productivity of cows with the first calving depending on live weight and average daily gains of heifers during rearing studied. The data of animals of Ukrainian Black-and-White dairy breed of Kyiv factory type used for the research. Every three months, from birth to 18 months of age, heifers were determined live weight and average daily gain. According to the indicators of weight growth, the heifers divided into 5 groups of the standard deviation principle from the mean. In animals included in these groups studied the performance of the first lactation. It found that obtaining a live weight of 3-month-old heifers over 127 kg can significantly reduce the age of the first calving. The advantage over animals belonging to the groups with less weight is 2.7-3.5 months. Increasing the live weight of heifers at 12 and 15 months also allows reducing the age of the first calving. Moderate (less than 722 g per day) growth of heifers at the age of 6-9 months also has a positive effect on the reduction of the age of the first calving. The weight of newborns heifers during lactation was associated with first calving cow’s milk yield. Heifers born with the lowest live weight (less than 28 kg) had after the first calving milk yield per lactation 145… 1956 kg more than in other groups. The live weight of 3-month-old heifers is of the greatest importance for the formation of high milk productivity of cows. Obtaining live weight of heifers of this age 117-127 kg with an average daily gain of 902-1037 g provided in first the lactation the largest milk yield with an advantage over animals of other groups up to 3119 kg. In older age periods, the influence of growing heifers on the formation of milk productivity is less pronounced, and the optimal live weight and growth rate was at the level of the average size of the herd. The research results can used to optimize the growth plans of heifers and their selection.

The objective of the study is to determine, whether the growth retardations of replacement cows are admissible, and in which periods of culture they most significantly affect the further productivity of the cows. The subject of the analysis was the number of animals who at the age of 15 months had the live weight no less than 300 kg (which complied with the breed standard or was inferior to the requirements for 10 % maximum). The animals were divided into 5 groups. The first group included the animals with growth retardation before the age of 3 months. The second one – at the age of 3-6 months; the third one – 6-9 months and the fourth one – 9-12 months. The fifth one was the control group, without growth retardation. The growth retardation referred to the live weight reduction at the end of the period in comparison with its beginning or the average daily weight gain less than 500 g. The authors measured the live weight, first lactation productivity and the lifetime productivity of the animals. It has been established that the growth retardation of the heifers before the age of 3 months negatively affected the growth rate in the following three-month period. They can completely compensate the growth retardation only at the age of 18 months. The other group animals compensated the live weight retardation in comparison with the control group by the age of 15 months. The firstlings which had the growth retardation at the age of 0-3 and 3-6 months, has the highest milk productivity. The same trend was observed in milk fat and protein output and the age of the first calving. However, in the growth retardation group the livability of firstlings, the number of lactations and the productive live was worse. The lifelong milk yield in the growth retardation group was 15-37 % lower than in the control group. Growth retardation at the age of 6-9 months negatively affected the higher lactation productivity. The highest daily milk yield in this group of cows was lower in the control group by 14 % (p < 0.05). Therefore, growth retardation had no negative effect on the milk yield of the firstlings, but resulted in lower survival of the animals, shortened the productive life and lifetime yield. The later the growths retardation occurs, the sooner the heifers can compensate it and the lower is its effect on the lifetime productivity of the cows. In view of the reduction of lifetime productivity, it is purposeful to draft out the animals with the growth retardation.