Field evaluation of a technique for transcervical intrauterine insemination of ewes

Abstract

In this study, three groups of ewes were inseminated with a transcervical intrauterine technique in order to evaluate the suitability of the technique for a commercial artificial insemination (AI) program using frozen semen. The ewes were synchronized into estrus with vaginal pessaries and pregnant mare serum gonadotrophin (PMSG) and were inseminated between 48 and 55 h following pessary removal. In Flock I, maiden and multiparous ewes (n = 12) received fresh semen containing 400 × 10 6 spermatozoa. Flock II was divided accordingly: 40 multiparous ewes were inseminated with frozen semen using the transcervical technique and 40 ewes were inseminated laparoscopically with frozen semen. In Flock III, 38 multiparous ewes were inseminated transcervically with frozen semen containing 150 × 10 6 spermatozoa. Pregnancy diagnosis was based on blood progesterone analysis 18 d following breeding, and real time ultrasound examination at 40 d. Pregnancy rates were 50, 50 and 68%, respectively, for the three groups inseminated transcervically and 70% for the ewes inseminated laparoscopically. The lambing rates were 50, 55 and 40%, respectively, for the ewes inseminated transcervically and 65% for the ewes inseminated laparoscopically. Lambing results were confirmed by matching the breeding dates to the lambing dates. These results demonstrate that the described technique is suitable for further evaluation using frozen semen in a commercial sheep AI program.