Synchronization of oestrus in the Boer goat doe: Dose effect of prostaglandin in the double injection regime

The administration of different doses (62,5; 125 or 250 ~g per injection) of a prostaglandin analogue (cloprostenol) 14 days apart (in the double injection regime), proved that oestrus can be synchronized very efficiently in the Boer goat doe, at all the doses. Of the does 77,1% responded with oestrus to the first cloprostenol injection. An increase in the dose of cloprostenol was not accompanied by a significant increase in oestrous response (93,8%, 87,5% and 100,0% for the three doses, respectively). The time from prostaglandin administration to oestrus was significantly (P < 0,05) shorter following the double injection prostaglandin regime when compared to the time after a single injection (mean 55,3 and 62,4 h respectively). A significant (P < 0,01) difference in oestrus duration was found between the first and second injections of prostaglandin (mean of 30,9 and 41,9 h respectively). The mean serum progesterone concentration fell rapidly (± 70%) within the first 6 h following the second prostaglandin injection. The mean serum LH concentration following the second injection of prostaglandin varied between 0,23 ng/ml and 10,1 ng/ml for the three treatment groups. A mean conception rate of 58,1% was achieved following AI for the different treatment groups. This study emphasizes the potential of this prostaglandin analogue as a synchronizing agent in Boer goat does. S. Afr. J. Anim. Sci. 1986, 16: 146 -150