The Effects of Oxytocin and PGF2α Injections on Semen Quality and Libido in Buck

The aim of the present study was to evaluate the effects of exogenous oxytocin and PGF(2 alpha), on seminal quality and libido sexualis in bucks. To investigate the role of these hormones on male fertility, semen samples from 20 Norduz bucks (3-4 years of age) were collected with an artificial vagina twice a week with five replications in breeding season. Bucks were randomly assigned to five groups, control group was administered with 2 ml of sodium chloride, 0.996 (w/v)) i.m., whilst the experimental groups were administered with oxytocin 10 IU, i.v. (Group 1, n = 5), oxytocin 20 IU, i.v. (Group 2, n = 5), PGF(2 alpha), 5 mg, i.m. (Group 3, n = 5) or PGF(2 alpha) 10 mg, i.m. (Group 4, n = 5) 20 min before each collection. There was no statistical difference between the treatment groups in terms of motility (P>0.05). However, semen volume, concentration, abnormal spermatozoa rate, intact membrane rate and libido results were statistically significant among the different groups (P<0.05). As a result, administration of 20 IU oxytocin twenty minutes prior to semen collection in bucks did not improve overall semen quality, however, libido, semen volume, and sperm concentrations were increased. In contrast to oxytocin, PGF(2 alpha) administration has led to a slight decrease in libido and has shown moderate effects on semen quality.