The Time of Artificial Insemination with Cooled Semen does not Affect the Pregnancy Rate in Anestrous Goats

Abstract

Background: The time of artificial insemination (AI) concerning ovulation is one of the main factors that affect the pregnancy rate. This study aimed to compare the time of AI with cooled semen in anestrous goats treated with progesterone (P4) plus hCG-based protocol and the effect of management condition on pregnancy rate. Methods: Forty-nine crossbred (local x dairy goats) and thirty-nine Alpine anestrous multiparous goats managed under extensive and intensive production systems respectively, were used (June, 25°N). Goats were treated with 20 mg of P4 followed by 100 IU of hCG 24 h later. On the day of hCG administration (Day 0), goats in each management system were allocated randomly to each of the two treatment groups. Goats in the first group received a fixed-time AI (FTAI) at 48 and 60 h after hCG whereas goats of the second group received a FTAI at 60 and 72 h with cooled semen. Goats were examined by transrectal ultrasonography (7.5 MHz) 45 days after AI to determine the pregnancy rate. Result: There was no significant difference in pregnant goats inseminated at 48 and 60 h (46.8%, 22/47) or 60 and 72 h (46.3%, 19/41) after hCG administration (P greater than 0.05). There was a tendency for a higher pregnancy rate in intensive compared to extensive management conditions (P=0.09) and no interaction was detected between the time of insemination and the management condition system (P greater than 0.05).