Efficiency of using different schemes for synchronizing the sexual heat of heifers in beef cattle breeding

In beef cattle breeding, the transfer of mature herd to a seasonal reproduction system takes time and may be accompanied by a decrease in the yield of young animals. To avoid this, various schemes for synchronizing sexual heat have been developed. Of these, the most effective are double administration of prostaglandins and a combination of prostaglandins with releasing hormone. But even so, the fertilisation rate from frontal insemination is on average 40 %. A reserve for increasing efficiency is the combined use of hormonal drugs and adaptogens in synchronization schemes. Four groups of the Kazakh White-Headed heifers of 40 heads each were formed for comparative tests. Sexual heat was synchronized in all groups according to the following protocols: in I group - a double injection of estrophane, in II group - a double injection of estrophane and two simultaneous injections of cresacin (adaptogen) solution, in III group - the Ovsynch scheme, in IV group - the Ovsynch scheme and two simultaneous injections of cresacin solution. Frontal insemination was performed in each group, fertilization was taken into account, and the economic effect of synchronization was calculated. The results of fertilization were 42.5% in I group, 47.5% in II group, 40.0% in III group, and 50.0% in IV group. The reduced fertility rate in III group is due to a stronger stress effect on animals when performing the Ovsynch scheme in beef cattle breeding. The maximum result was obtained in II and III groups, i.e. with the combined use of hormonal drugs and cresacin. When calculating economic indicators, similar results were obtained: the cost of maintaining infertile heifers decreased in I group by 76296.68 rubles, in II group by 83330.36 rubles, in III group by 72880.64 rubles, in IV group by 91642.4 rubles, Therefore, the inclusion of cresacin in the synchronization scheme of sexual heat of heifers is an economically beneficial measure.