Influence of feed intake during individual weeks of lactation on reproductive performance of sows on commercial farms

Abstract

The influence of average daily feed intake (ADFI) during different weeks of lactation on the reproductive performance of sows was investigated. Data contained 18243 farrowing and 15671 ADFI records for sows with lactation length between 7 and 22 days from 30 commercial farms. The regression coefficients of ADFI during individual 3 weeks of lactation on the three measures of reproductive performance were compared. The coefficients of ADFI on natural log-transformed weaning-to-service interval were larger for week 2 (−0.0529 for parity 1; −0.0579 for parity 2 or greater) than for weeks 1 (−0.0340 for parity 1; −0.0277 for parity 2 or greater) and 3 (−0.0295 for parity 1; −0.0188 for parity 2 or greater). The coefficients of ADFI for weeks 2 (0.6667) and 3 (0.6301) in parity 1 sows on litter weight at weaning were larger than that of week 1 (0.3051). In parity 2 or greater, the coefficient of ADFI for week 3 (1.2787) was intermediate between those for weeks 1 (1.0533) and 2 (1.6956). No differences were found between the coefficients of ADFI during individual weeks on subsequent litter size. It is suggested that increased feed intake during early and mid-lactation reduces weaning-to-service interval more than it does during late lactation, and increased feed intake during mid- to late lactation increases litter-weaning weights more than it does during early lactation.