The influence of hormonal interference on pregnancy rate in recipient cows

The article presents recent opinions concerning the efficiency, time-period, forms of application anti reasons for biotechnical manipulations which involve supplementing cows with hormones such as progesterone, GnRH and hCC. A number of opinions confirm the positive influence these substances have on pregnancy results in cases where they are applied directly after embryo transfer. Other data, however, indicate that there is no correlation between hormone supplements and pregnancy results, The influence of factors such as heat synchronisation, quality of embryo and/or its development stage have a greater influence on pregnancy rate than hormone application.