PS2-10. Does AI Using Relatively Few Sperm Optimize Fertilization in the Pig?.

Abstract The use of artificial insemination (AI) in swine is a management tool that is practiced at a global scale such that >90% of the world’s pigs are bred using AI with fresh semen. Historically, AI doses have been produced using multiple billions of sperm per dose allowing acceptable farrow rates and total pigs born per litter. Following the cattle AI industry pattern, there is a continued movement within the swine industry to produce and utilize AI doses having fewer sperm per AI dose. Unexpectedly, more than a few swine producers have observed an increase in total pigs born when switching to using AI doses possessing less sperm than previously used. The objective of this report is to provide retrospective data based on thousands of services across dozens of farms showing a slight increase in number of pigs born when a production system chooses to use an AI dose with less total sperm. A secondary objective is to propose a possible explanation for the trending results. Data from a particular sow farm is provided as example. We compared farrow rates (FAR) and total number of pigs born (TBN) for sows receiving 2.5 billion total cells/AI dose (n = 758 matings) versus 2.25 billion total cells/AI dose (n = 721 matings) when bred over a 12-week period within farm. Matings were performed consecutively (i.e. 6 weeks at 2.5B and 6 weeks at 2.25B) using 70mL dose volume as conventional AI with technicians unaware of the cell number change. The mean FAR and TBN trends were 85.9% and 15.9 versus 90.0% and 16.5 for the 2.5B and 2.25B, respectively. We propose that a reduction in polyspermy may contribute to the upward fertility trend because fewer sperm may reside at the sperm reservoir leading to an increase in fertility.