Fertility Response of Sows Receiving Oxytocin, Lecirelin and Caffeine in Semen

Maximizing reproductive output during the sow’s lifetime decreases production costs in commercial breeding herds. Artificial insemination (AI) provides sanitary and zootechnical benefits over natural mating but can be associated with a decrease in sow reproductive performance; it has been suggested that inadequate stimulation of the sow during AI may compromise myometrial contractions, impairing sperm transport to the oviduct sperm reservoir and so potentially reducing subsequent fertilization rate and litter size. The objective of this study was to determine effects of a novel seminal additive on fertility of multiparous sows during two consecutive years. A total of 2,639 sows were assigned to receive seminal additives of either 2 IU oxytocin + 5 µg lecirelin + 2 mM caffeine (SF; n = 841) or to serve as controls (CON; n = 1798) during the periods of January to April, May to August, and September to December. Sows were inseminated at detection of estrus and at 24 h intervals while exhibiting estrus. Additives were introduced to insemination doses 15 min prior to the first AI only. The semen used for the study was diluted in a commercial extender, packaged in collapsible squeeze bottles containing 3 × 10⁹ sperm in 80 mL, and stored at 15ºC for no longer than 48 h after collection. Differences in farrowing rates and total litter size between groups were examined by logistic regression and two-way ANOVA, respectively. Compared to CON, SF increased farrowing rate (91.8% vs. 88.0%; P ≤ 0.01) and litter size (14.8±0.23 vs. 13.8±0.19; P ≤ 0.0001) throughout the year. There were no significant differences for control or treated animals between the 3 different periods. We conclude that the administration of a combination of oxytocin, lecirelin and caffeine to semen doses 15 min prior insemination will positively affect sow fertility.