Practices Affecting the Conception Rates Following Oestrus Synchronisation in Cattle

Artificial insemination (AI) is the most common biotechnological method used in cattle breeding. One of the most important factors on the success of AI is true determination of the oestrus. By using various oestrus synchronisation methods in cattle, the problem concerned can be resolved. Numerous researchers conducted comparative studies about the effects of different synchronisation methods on the pregnancy rate. Also, some workers investigated the effects of different synchronisation methods by using certain substances on the pregnancy rate. Considering pregnancy, some researchers stated that there was no difference between different synchronisation methods. On the other hand, some expressed that there was a marked difference between different synchronisation methods based on the pregnancy rate. Further, they indicated that there was difference between heifers and cows of same breeds exposed to the same synchronisation method. To increase the pregnancy rate and success of synchronisation, some vitamins and hormones such as Vitamin E, GnRH, Flunixin meglumine, Beta-carotene and eCG are used along with synchronisation methods in numerous studies. In this review, an up-to-date data about the factors being used along with synchronisation methods and affecting the fertility rates are presented.