Source: University of Nebraska-Lincoln
Dempster M. Christenson, research technician and graduate student
Jordan M. Thomas, assistant professor, Animal Science (University of Missouri)
Daniel J. Kelly, producer, Sutherland, NE
Rick N. Funston, full professor, animal science, West Central Research and Extension Center, North Platte, NE
Summary with Implications
This study compared pregnancy rates of beef heifers artificially inseminated with multi-sire semen versus single-sire semen. It was hypothesized that pregnancy rates would be higher with multi-sire semen. Heifers were inseminated with semen from one of three single sires or from a mix of those sires. Pregnancy rates did not differ significantly. Paternity testing showed that sire parentage could be unequal when using multi-sire semen. In conclusion, producers can expect similar pregnancy rates with both single-sire and multi-sire semen, but progeny may have unequal sire representation.
Conclusions
Methods that increase pregnancy rate to AI (artificial insemination) in heifers increase the productivity of the herd by increasing the lifetime productivity of those heifers and their progeny while decreasing the costs associated with development of heifers who take more time and feed to produce a calf. A greater number of observations from this ongoing research may provide further insight on the effects of multi-sire treatment on heifers from multiple years. Current results indicate pregnancy rate to AI with MS and SS treatment is not significantly different, but the percentage of calves from each sire within the MS treatment tended to be. However, more research is required to solidify these conclusions and understand what unexplored interactions may be influencing these results.
