THE EFFECT OF A BETA-ADRENOCEPTOR ANTAGON IST ON THE EXPULSION OF THEPLACENTA OF CATTLE

The beta-adrenoreceptor antagonist carazolol, administered intravenous ly to 72 cows, predominantly german black pied, immediately post partu m enhanced the spontaneous expulsion of the placenta within 6 hours of calving (40.4% vs 30.1%; p < 0.01). The difference between the experi mental and control groups was most marked in cows which had been subje cted to obstetrical surgery (27.1% vs 2.9%; p < 0.005). Differences we re also observed between treated and control groups of cattle which ca lved normally or for which mild assistance was required (8.6% vs 12.9% ) and of cattle which experienced dystokia (35.1% vs 55.9%). However, these were not statistically significant.