1a.Objectives (from AD-416)
To develop a technique that will enable sheep to be inseminated with frozen-thawed semen using a non-surgical artificial insemination method. Development of this technique will enable sheep producers to better utilize the genetics (semen) of desirable rams for flock improvement and provide the National Animal Germplasm Program (NAGP) with a more efficient, cost effective method for utilizing frozen ram semen samples contained in the repository.
1b.Approach (from AD-416)
The estrous cycle of ewes will be synchronized. Ram semen will be collected and cryopreserved. The ewes will then be inseminated using our newly developed technique at a designated time with fresh or frozen-thawed ram semen. The non-return to estrous rate, the pregnancy rate, and the prolificacy rate (number of lambs born per ewe lambing) will be determined. The results will then be evaluated to refine the techniques to improve the fertility rate in subsequent years.
The research in the third year of the project focused on exploring alternative techniques for artificial insemination, and improving the methods for collection of semen for cryopreservation and subsequent inclusion in the repository or for use with artificial insemination. The new artificial insemination method proved simpler than the method that we initially developed. However, no fertility was achieved with either method. We believe the causes of this are due to the difficulty in determining the proper time to inseminate and due to the quality of the semen which was used for the inseminations. The semen used was from repository samples, and is of acceptable quality, however it was originally frozen for the purposes of surgical insemination. Because of this the samples had fewer sperm per straw and was of a lower quality than what is required for a non-surgical insemination which was performed in this experiment. Exploration of alternative methods of semen collection proved beneficial in comparison to past methods because the new approach enables the rams to experience less stress, produce higher quality samples, and is less physically demanding for the collectors. Because of these findings, future experiments will incorporate the new techniques for semen collection and artificial insemination. ADODR monitoring for this project is monitored by regular phone contact, by a site visit in December 2010 for performance of the research, and by email.