Influence of cattle calving season influence on index of productivity and reproduction

The aim of the work: to analize and compare influence of cattle calving season on index of productivity and reproduction. The goals of the work: To Evaluate and compare influence of cattle calving season on milk yield and its composition. To evaluate influence of cattle calving season on reproductive index. To compare influence of cattle lactation and calving season on productivity and reproductive parameters. Influence of cattle calving season on milk yield, fat content, protein content, somatic cell count in the milk (thousand/cm3) over a season and reproductive traits was analyzed. Productivity was compared between lactations and seasons; production and reproduction parameters were compared between cows of different lactation period each season. Applied confidence index was equal to p<0,05. Milk yield of cattle that calved in autumn was bigger than cattle that calved in winter and spring by 203 kg and 591 kg (p<0,05) respectively. Milk content of protein and fat of cattle that calved in autumn was bigger than of cattle that calved in spring by 0,08% (p<0,05) and 0,14%(p<0,05) respectively. Service interval of cows that calved in spring was shorter than of cows that calved in autumn by 25 days (p<0,05). Insemination index of cows that calved in autumn was 0,51 times (p<0,05) bigger than that of cows that calved in summer. During every lactation, biggest milk yields were produced by cows that calved in autumn. During the second and the third lactation of spring, milk yields were smaller than those of autumn by 893 kg and 1093 kg respectively (p