Abstract
Our objective was to determine the impact of controlled feeding for 3, 5, and 7-d post-farrowing compared to ad libitum feeding during lactation on gilts and sows reproductive and litter performance during the summer period. A total of 404 PIC Camborough® gilts and sows were used. Females were randomly allotted in a randomized complete block design based on body weight and caliper withing parity category to one of four treatments. All females were fed 2.0 kg/d of a common lactation diet containing 3.335 Mcal of metabolizable energy/kg and 1.05% standardized ileal digestible lysine from loading into the farrowing room until the day of farrowing. After farrowing, the daily amount of feed provided to each female was individually adjusted according to the treatment. Treatments consisted of: ad libitum feed allowance from d1 post-farrow to weaning (AdLib) or step up feed allowance in small increments for the first 3 days post-farrow (3dStep-Up), for the first 5 days post-farrow (5dStep-Up) or for the first 7 days post-farrow (7dStep-Up) followed by ad libitum feed allowance until weaning. Females were considered the experimental unit for all analysis. The data were analyzed using generalized linear mixed models with the lmer and glmer functions in R. Results showed no evidence of significant differences across treatments (Table 1; P > 0.10) on sow body weight at weaning, body weight change during lactation, or caliper measurement at weaning or body condition losses during lactation. Sows fed AdLib had higher cumulative feed intake for the first 7d post-farrow (P< 0.001), with sows fed 3dStep-Up, 5dStep-Up, and 7dStep-Up eating 14%, 20%, and 32% less feed in the first week post-farrow, respectively, compared to sows fed AdLib. Overall lactation feed intake was significantly lower for sows fed a 7dStep-Up feeding program compared to sows fed AdLib or 3dStep-Up, with sows fed 5dStep-Up intermediate. There was no evidence for treatment differences in litter growth or piglet growth rates during lactation, or proportion of weaned pigs relative to litter size after cross-fostering. In summary, under the conditions of this study, allowing sows ad libitum feeding post-farrowing resulted in higher lactation feed intake compared to a 7dStep-Up feeding regimen. However, no evidence for treatment differences were observed for sow weight and body condition changes nor piglet performance during lactation.