Effect of pregnant mare serum gonadotrophin (PMSG) and route of administration after progestagen treatment on oestrus and LH secretion in the Boer goat
During the breeding season, 94 mature Boer goats were treated with intravaginal progestagen sponges (MAP, 60 mg) for a period of 14 days. Upon sponge withdrawal, goats received 300 i.u. PMSG either subcutaneously (n = 32) or intramuscularly (n = 30). A control group was not treated with PMSG (n = 32). Administration of 300 i.u. PMSG at sponge withdrawal had no significant effect on the number of animals exhibiting oestrus in each group. Interval from sponge withdrawal to commencement of oestrus was shorter for intramuscular (P < 0.01) and subcutaneous (P < 0.05) PMSG-treated groups than controls, with the route of PMSG administration not having a significant effect. Mean duration of induced oestrus was significantly shorter (P < 0.05) in the control group. The interval from onset of oestrus to the occurrence of the preovulatory LH peak was shorter (P < 0.05) in the group receiving PMSG subcutaneously. © 1990.