ELSEVIER PROSTAGLANDIN F2a ADDED TO EXTENDED BOAR SEMEN AT PROCESSING ELICITS IN VITRO MYOMETRIAL CONTRACTILITY AFTER 72 HOURS OF STORAGE H. Cheng’, G.C. Althouse’ and W.H. Hst? ‘Department of Biomedical Sciences, Iowa State University, Ames, Iowa, 50011 ‘Department of Veterinary Clinical Medicine, University of Illinois, Urbana, Illinois, 61802 USA Received for publication: October 12, 2000 Accepted: January 10, 2001 ABSTRACT Improved fertility will maximize productivity of the swine industry. Myometrial contractility is an essential component in the fertilization process because it is the mechanism by which spermatozoa are transported to the site of fertilization. In the present study, we evaluated the potential use of PGF2a supplementation to the extended pig semen in regard to inducing myometrial contractility of sows. Extended boar semen (80mL)was supplemented with PGF2a (5 mg) for 72 hat 17 k 1” C. Cumulative doses of 0.1, 1, 10 and 100 pL of the mixture were tested on uterine strips obtained from die&us sows. An increase in myometrial contractility was recorded with PGF2a supplementation when compared to extended semen or extender treatment alone after 72 h of incubation. Addition of PGF2a to the extended boar semen at the time of the experiment did not differ from the 72 h treated group. The results from this study support that PGF2a preparations can be added to extended doses of boar semen at processing to enhance myometrial contractility at the time of insemination for up to 72 h. 0 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 2001 by Elsevier Science Inc. Key words: PGF2a, boar semen, myometrial contractility, improved fertility INTRODUCTION Assisted reproductive technologies,,such as AI, have greatly increased breeding efficiency in the swine industry. Stimulation of the female during the AI process is quite different from the stimulation she would receive during a natural mating. Myometrial contractility is an essential component in the fertilization process because it is the mechanism by which spermatozoa are transported to the site of fertilization (12). In an effort to stimulate certain physiological events (e.g., uterine contractility) associated with breeding, several research groups examined the use of hormonal supplementation to the pig semen dose at the time of breeding. Products investigated have included estrogen (3,6), oxytocin (7, IO), prostaglandin (5) and relaxin (11) analogs. Reports addressing the supplementation of PGF2a to a pig semen dose at the time of AI indicated significant improvements in overall fertility (5,9). Unfortunately, with the large number of sows needing to be bred per day on many commercial farms, oft-times it is not feasible to compound the large Acknowledgments We thank Mr. Laveme Escher for technical assistance and the Iowa Select for donating boar semen. The work was funded by Pharmacia & Upjohn. aCorrespondence and reprint requests. Theriogenology 55:1901-1906, 2001 0093691WOl/$-see front matter 0 2001 Elsevier Science Inc. PII: 50093-691X(01)00531-3