Reproductive performance and estimates of labor requirements associated with combinations of artificial insemination and natural service in swine

A study was conducted to examine effects of mating systems composed of natural service (NS) and AI in swine on farrowing rate, litter size, and labor requirements. Sows and gilts were bred once per day via one of the following treatments (d 1/d 2): NS/NS, NS/AI, AI/AI, and NS/none. Gilts bred with NS/AI, AI/AI, and NS/NS had higher (P < 0.05) farrowing rates than gilts bred with NS/none matings. Similarly, farrowing rates were higher (P < 0.05) in NS/AI than in NS/NS gilts. Numbers of pigs born alive were greater (P < 0.05) in NS/NS, NS/AI, and AI/AI than in NS/none gilts. In sows, a treatment x time interaction (P < 0.01) was present for farrowing rate. In the AI/AI treatment, farrowing rate increased (P < 0.01) from 70.0% (wk 1 through 3) to 88.5% (wk 4 through 10). Farrowing rates were 87.3, 93.2, and 76.0% in the NS/NS, NS/AI, and NS/none groups, respectively, and did not change (P = 0.72) over time. Sows bred via NS/NS and NS/AI had larger litters (P < 0.05) than Ns/none sows. In the present study, if four or more sows and gilts were bred, then AI required less (P < 0.05) time per animal than NS. Furthermore, gilts required more P < 0.05) time for breeding than sows. Results from this study demonstrate that gilts and sows responded differently to combinations of NS and AI in terms of reproductive performance. In addition, differences in labor requirements per sow or gilt between NS and AI matings were dependent on parity and daily breeding demands.