Evaluation of different procedures used for insemination of cows of Holstein cattle

The high-production dairy cows have problems with fertility, because there is negative correlation between fertility and milk production. Very often the problem with fertility is connected with cumulative number of quiet, indistinctive ruts. Such a problem causes prolongation of service period, increases consumption of insemination doses and rises the number of veterinary acts. Therefore new possibilities are searched to ensure satisfying fertility of cows.The objective of this work was to evaluate different procedures for insemination of cows of Holstein cattle. The research proceeded at agricultural company Kosova Hora, which has two stables with dairy cows. The controlled reproduction by means of hormones is used at cow-shed in Janov, whereas the natural reproduction when a cattleman looks for rutting cows is used at cow-shed in Kamenice. The way of stockbreeding, stabling and feeding was very similar in both cow-sheds. There were 203 dairy cows of Holstein cattle (H100%) or crossbreed dairy cows of Czech spotted cattle (H75 and more) included in survey. Reproductive indices (such as insemination interval, service period, meantime and the age of a cow when first calves) and also indices of milk efficiency in 1 kg of milk (for 100, 200 and 305 days of lactation) were monitored. The period of insemination interval was about 16,81 days shorter in the cow-shed where hormones (84,36; 101,17 days) were applied with confirmation statistically highly significant difference at the level of significance P < 0,001. There was no statistically significant difference when the duration of service period was measured. The duration of service period was on the same level in both cow-sheds (162,12; 162,84 days). When the outcomes of both cow-sheds were summarized the difference in the duration of meantime was found. With usage of synchronization the difference was 19,20 days, but without statistical demonstrativeness (P < 0,05) at the level 410,28; 429,48 days. When indices of milk efficiency were measured there were not found statistically significant differences as for the whole lactation (9 926,19; 9 749,48 kg of milk) and also for individual sections of lactation (100 days about 30,96 kg of milk more at the cow-shed without synchronization; 200 days about 78,44 kg of milk more at the cow-shed with synchronization)