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Physiology Symposium I: Updates on Frozen Semen Utilization and Associated Technologies across Species Recap

By: Dr. Simone M.M.K. Martins, University of Illinois, Urbana-Champaign

Dr. Mitch Hockett, ST Genetics, began the symposium discussing some relevant points for the significant impact of artificial insemination in dairy Industries. He said that the increase in the lifetime of sperm, the introduction of antibiotics to reduce any sort of infection, reduction of semen dose concentration, and cryopreservation were some main factors responsible for that. Besides, this technology (AI) has improved milk production and increased the number of progeny from elite males. In elite females, when associated with tools like multiple ovulation and embryo transfer (MOET), oocyte pickup (OPU) and in-vitro fertilization (IVF), and sex-sorted semen led to an increase in genetic progress. They resulted in an improvement in profit for the dairy industry.

Dr. Phillip Purdy, USDA National Animal Germplasm Program, used his talk “What quality and Fertility Should we Expect when using Semen Cryopreservation and AI with Livestock? A Comparison across Species” to clarify that the germplasm program has expertise in many areas of assisted reproductive technology. The program has expertise in semen and embryo collection, cryopreservation and vitrification, in-vitro fertilization, and embryo transfer applied to agricultural species (beef and dairy cattle, goats, pigs, poultry, sheep). Dr. Purdy commented about some differences in the fertility obtained among species studied. Furthermore, he also explained some factors that could influence fertility like insemination dose, type of extender, the estrous synchronization, breed, artificial insemination method, and the interval between insemination to ovulation, and that to achieve fertility across any one of these species is needed to match the effects cited above.

Dr. Brandon Hopkins, Washington State University, began his presentation “Honey Bee Semen Cryopreservation” by discussing that AI is not necessarily new but has been slow to be adopted by the industry. Large-scale commercial queen producers rely on the artificial insemination of queens to produce their breeder stock.  Artificial insemination is a valuable tool that allows the controlling of mating and breeding stocks. Dr. Hopkins described how semen collection is made, the steps for semen cryopreservation, as well as artificial insemination or also called instrumental insemination. The use of cryopreservation can be a valuable tool to conservation breeding because of honey bee lineage in the world, and some of these had been lost because it is challenging to maintain these lineages in colonies.

Dr. André Andrade, University of Illinois, used his talk “Analysis of Cryopreserved Semen Quality: With the Tools Available, What Is Possible to be Interpreted” to show that classical methods to assess sperm quality using fluorescent probes, flow cytometry, and a computerized semen analysis system can evaluate the sperm characteristics considered with the potential to fertilize the oocyte, but it is impossible to predict the fertilizing potential accurately. Dr. Andrade commented that other factors could affect fertility, such as breed, age, semen manipulation, nutrition, different ejaculates from the same individual, environment, and all these factors can modify the cryotolerance capacity of sperm. Technologies as proteomics, metabolomics, lipidomics, and miRNAs can be used to look for markers present in the ejaculate before the cryopreservation process, and in this way, they can predict the sperm cryotolerance and, shortly the fertility.

An unedited recording of this symposium can be found on the meeting website.