Administration of recombinant bovine somatotropin (rbST) at the time of breeding in superovulated fertile and subfertile ewes

Abstract Two experiments were conducted to evaluate the effects of the administration of 125 mg rbST at the time of breeding on fertile and subfertile superovulated ewes – in terms of the ovulation rate, embryo yield and embryonic development. In addition, the effects of the treatment on the plasma progesterone concentrations and interferon-tau (IFNT) expression in the embryos were evaluated in the fertile animals. In the first experiment, carried out on fertile superovulated ewes, the treatment significantly increased the ovulation rate ( p p p p