Date of this Version
Published in Proceedings, Western Section, American Society of Animal Science (2009) 60: 290-293.
Transcervical artificial insemination (AI) with sheep is not frequently used in the US due to low fertility rates. Consequently, laparoscopic AI has been employed to circumvent this situation. The problem with this technique is that while it provides satisfactory levels of fertility the degree of technical expertise necessary to perform the procedure, the costs associated with purchasing equipment, and/or the costs of hiring an inseminator are prohibitive for many producers. Therefore, the purpose of this study was to investigate a transcervical method of AI that is nonsurgical, simple to perform, and inexpensive. The estrous cycles of 40 ewes were synchronized using CIDRs for 12 days. Upon CIDR removal vasectomized rams (n = 4) fitted with raddle harnesses were turned out with the ewes (one ram per 10 ewes in separate pens) to detect estrus. After ewes were observed in estrus they were removed from the pen and inseminated twice with either fresh (n = 19 ewes) or frozen-thawed semen (n = 21 ewes) 15 and 24 hours after observed estrus using a spiral sow insemination catheter. Least square means for lambing rates for fresh and frozen-thawed treatments were 55% and 9%, respectively (P< 0.05). However, mean prolificacy rates did not differ (P > 0.05) for fresh (1.3) or frozenthawed (1.0) treatments. These results demonstrate that this economical, easy to use method of non-surgical AI for sheep is feasible but the results indicate that improvement is needed. Consequently, future studies will be performed with the goal of improving fertility with this technique, particularly when utilizing frozen-thawed semen, which should prove valuable to sheep producers.