Reproduction Abstracts

Introduction: Bio-stimulation is the stimulus provoked by the presence of a male which induces fertility through genital stimulation or other external cues. In animals, courtship and foreplay which precede mating have reciprocal effects on sexual and reproductive milieu of both sexes. An increase in male exposure to females will also tend to evoke increases in reproductive capacity of both sexes. The study evaluated reciprocity of boar exposure on testicular characteristics and subsequent fertility of their female counterparts.

Materials and methods: Twenty-four South African Mukota boars were allowed 0, 30, 60, 90 or 120 min of fence-line exposure to 120 sows, twice daily during oestrus detection protocols, throughout the 120 days observation to evaluate reciprocal stimulatory effects of boar exposure on testicular characteristics and subsequent fertility of sows following artificial insemination (AI). Non-return rate (NRR) was evaluated as the proportion of females that did not return to service from the overall AI sows.

Results and discussion: Boar exposure for 120 min caused the weight of the testicles to hypertrophise by 96.5%, with the highest total daily sperm production (22.3±2.1×10⁹ per testis) and total Leydig mass (113.5±8.2 g) and largest tubular values. Semen collected following 120 min boar exposure gave highest non-return rate (93.5±2.9%), farrowing rate (88.7±5.1%,), litter size (14±0.02) and live piglets (12±0.06). Results suggest that prolonged (120 min) fence line boar exposure has reciprocal effects on boar testicular characteristics leading to significant improvements in the fertility rates of breeding sows.

Keywords: Sus scrofa mukota, bio-stimulation, testicular hypertrophy, female fertility