Effect of different mating stimuli on induction of ovulation in the alpaca

TLDR: Results indicate that mounting accompanied by penile intromission is necessary to provide an adequate stimulus for lh release and subsequent ovulation in the alpaca.

Abstract: Summary. The ovulation response following different mating stimuli was studied in 177 adult female alpacas killed 72 hr after mating. Ovulation rates in females that received a mounting stimulus alone, either by aproned males or other females, were low and did not significantly differ from those controls which did not receive any stimulus. Single services by intact, or vasectomized males caused ovulation in 77 to 82% of the females, a significant increase over the previous treatments. Increasing the number of services by intact males to three within 24 hr, or interrupting services 5 min after their initiation, did not significantly affect ovulation or fertilization rates, as compared to single or uninterrupted services. Single hcg injections to females in oestrus induced ovulation in all cases. Results indicate that mounting accompanied by penile intromission is necessary to provide an adequate stimulus for lh release and subsequent ovulation in the alpaca.