Use of oxytocin for the prevention of early embryonic mortality in alpacas

Abstract

The objective of the present experiment was to test the oxytocin effect on embryonic survival during the luteolysis risk period in post-mating alpacas. Forty-three adult alpacas that were receptive to the male and bearing an ovarian follicle >7 mm of diameter were selected. They were mated with fertile males and the copula lasted for >10 minutes. Ovulation was secured with con 1 ml of GnRH i.m. (Day 0). Within the group of alpacas with a corpus luteum confirmed by trans-rectal echography on day 7, 30 were randomly selected and assigned into two similar groups. One group received 40 IU oxitocin on days 9, 10 and 11 post-mating days distributed in 4 doses of 10 IU every 5 hours. The second group was considered as control. The embryonic survival was evaluated based on sexual receptivity on days 8, 10, 11, 12 and 40 post-mating and confirmed on day 40 by ultrasonography. The oxytocin treated alpacas resulted with embryonic survival of 100% on days 8 and 10, 93.3% on days 11 and 12, and 86.7% on day 40 after mating, whereas non-treated alpacas had 100, 80, 66.7, 46.7 and 46.7%, on days 8, 10, 11, 12 and 40 after mating respectively, with significant differences between groups on days 12 and 40 (p<0.05). In conclusion, exogenous oxytocin reduced the embryonic mortality in alpacas before 40 days of pregnancy.