<p>It was estimated the conversion of feed into milk, content of urea, fat, protein, somatic cells in the milk of cows of different breeds in different seasons and months of the year. It was established that the peculiarities of the organization of feeding process significantly influence the productive indicators. Thus, in the conditions of a modern milk complex for 1500 cows with an unattached system of keeping in boxes and feeding with the use of mixed rations, the average value of feed conversion (the measures of digestibility of the feed when it "converted" into dairy products) is 1.38 kg of milk per kilogram of dry matter of<br />feed, and the ratio of fat to protein is 1.10, which is lower than the existing standards. It was established that changes in the conditions by months of the year significantly influenced practically all analyzed qualitative characteristics of milk. And this fact entails the corresponding monthly fluctuations of indicators of safety of products, emissions of by-products of metabolism, and, consequently, fluctuations of dairy cattle breeding impact on the environment and ecology. It was found that milk yield positively and significantly (P≥0.999) correlated with the consumption of feed dry matter (r = 0.454) and feed conversion rate (r<br />= 0.547). At the same time, the milk yield is negatively related to the fat content (r = –0.211) and the protein content (r = –0.192) in milk. The level of urea in milk positively correlates with the content of protein in milk (r = 0.130; P≥0.99). The influence of the factor "breed" on the following important economic-useful traits such as daily milk yield (η2 = 0.131) and feed conversion rate (η2 = 0.130) are proved.</p>

The analysis of variance of the breed's influence on the milk yield in the farms has established that there is no difference between the milk yields of Ukrainian black-and-white dairy breed and Ukrainian red-and-white dairy breed. Influence of breed on milk yields was not significant (P>0.05). Therefore, an assessment of feeding technologies and development of a model for prediction of milk yield were carried out without taking into account the breeds. Average duration of working action, called "feed unloading from the shovel", amounts 6.82±0.43 s without weighing and 14.94±3.61 s with weighing during loading. The measure of influence of the feed unloading type on the duration of that working action η 2 =0.217 (P<0.001). Coefficient of correlation between number of forage in feed mixture and: total number of working actions of feeder in cycle of feed preparation amounted 0.58 (P<0.01); specific number of working actions of feeder for service 1 cow in cycles of preparing of feeds was 0.41 (P<0.05); expenses of forage loader for servicing 1 cow in cycles of forages loading equaled 0.60 (P<0.05). The mechanisms of influence of ergonomic components' characteristics of preparation, delivery and distribution of feeds on behavior, milk productivity, labor productivity and efficiency of different technological processes were found and formalized. The model of evaluation of expected milk yields at the farm on base of feeding technology characteristics was developed. The model includes the variables: method of feeding of different forms of forages (total mixed / mixed + separately / separately), number of forage types in ration and method of dosage. The model describes 83% of variation of milk yields significantly (P<0.01). Ceteris paribus, the farms, which apply feeding a total mixed rations ad libitum, are capable to get milk yields on 1581-2585 kg higher than farms, which realize feeding technology less rationally.

The duration of productive use is a complex integral feature and is determined by both genetic and paratypical factors. This feature should ensure maximum milk productivity of animals, economic efficiency of dairy farms and generally limit the cost of raising and keeping cows. Research conducted in the experimental farms of state enterprises "Kutuzovka", Kharkov district of Kharkov region using cow’s Ukrainian black-and-white dairy breed (4038 cows). We studied the duration of productive use of cows divided into gradations according to the conditional bloodline for the Holstein breed, depending on the weight in the control age periods of cultivation (at birth, at 6, 12 and 18 months). The maximum value of the duration of productive use was recorded in the group of cows with a share of conditional blood for the Holstein breed up to 30% inclusive (the average duration of productive use is 2.77 lactations). The highest indicator of the duration of productive use of the studied animals was 4.09 lactations. Among cows with a share of conditional blood for the Holstein breed up to 30% longer produced those born with a weight of more than 40 kg (4.09 lactations), at 6 months of age weighed 100-149 kg, at 12 months – 200-249 kg, at 18 months of age – 350-399 kg. Among animals with a share of bloodline of 31-60 %, those that had a weight at the age of 6 months produced the longest: 155-190 kg (3.17 lactations), at 12 months – 250-299 kg (2.98 lactations), at 18 months – 350-399 kg (3.06 lactations). In the most numerous gradation with the share of bloodline for the Holstein breed 61-90 %, the longest productive use was characterized by animals born with a weight of 30-39 kg (2.12 lactation), at 6 months of age they weighed more than 200 kg (3.29 lactation), at 12 months-300-349 kg (3.40 lactation), at 18 months – 400-449 kg (2.82 lactation). The average duration of productive use of cows of this grade is quite low – in the range of 2.82-3.29 lactations. The highest degree of influence on the duration of productive use in this gradation of animals was recorded by the live weight factor at 6 months of age (η2 = 10.8). Сcomparative assessment of the cows gradation with a share of conditional blood for the Holstein breed of 91 % or more found that the longest productive use was characterized by cows that had a live weight at birth of 30-39 kg (1.93 lactation), in 6 months – 155-199 kg (2.73 lactation), in 12 months – 250-299 kg (2.87 lactation) and in 18 months – 350-399 kg (2.62 lactation). The degree of influence of live weight at this age on the duration of productive use of cows is insignificant, except for live weight at 6 months of age (η2 = 11.8).