Review Intrauterine (Transcervical) And Fixed-Time Artificial Insemination In Swine
North Carolina State University Swine Reproduction Research from 2002. A large portion of the current swine artificial insemination (AI) research is focused on a means to reduce the number of sperm required per service (i.e. estrus) without compromising sow farrowing rate or litter size. One strategy proposed to accomplish this is to decrease the number of sperm per insemination dose by depositing semen within the uterus (intrauterine), instead of the cervix, as is the case with natural mating and conventional AI. Based on the limited available data, intrauterine insemination may reduce the number of sperm required to achieve fertilization compared to conventional AI, but it may also increase the chance of causing or aggravating an existing cervical or uterine injury (post-insemination bleeding) and introducing a uterine infection. Insertion of an intrauterine catheter is more difficult in gilts than sows and requires a breeding technician to have more skill as compared to conventional AI. However, the adoption of non-surgical intrauterine techniques could allow other technologies like embryo transfer, frozen semen, and sexed semen to be adopted on a larger scale. An alternate strategy to reduce the number of sperm required per service is to reduce the number of inseminations by controlling the timing of the inherently variable processes of estrus and ovulation through pharmaceutical treatments (i.e. synchronization) and inseminating once at a fixed-time. A gonadotropin preparation (P.G. 600, Intervet, Inc.) is currently available, but more versatile and effective progestagen, GnRH, eCG, and hCG synchronization products exist that are not approved for swine use. The extent to which hormone synchronization treatments are utilized in the future will likely depend on their cost, efficacy, and ethical implications. At present, intrauterine and fixed-time insemination technologies are only being used for research and special genetic transfer situations in swine. Some form of commercial application may be on the horizon, but at this point, there is not enough data to determine if the benefits of these techniques would outweigh the costs. If a major reduction in the number of sperm required per service is achieved, it could substantially increase the economic and genetic efficiency of semen production, but it would also increase the need for accurate evaluation of semen quality.