The Effect of Lactation Dietary Protein on the Reproductive Performance of Early and Conventionally Weaned Primiparous Sows

Purdue University 1997 Swine Research Report. The use of segregated early weaning to develop high health status pigs is becoming increasingly common in the swine industry. Based on 1995 USDA statistics, 31.4% of the pigs in the U.S. were weaned at 10 to 20 days of lactation (Swine 95). Early weaning (17 day lactation) provides health status benefits that result in improved pig growth performance, and also allows sows to be cycled through the production system faster (more litters/sow/year). However, early weaning can have some potential consequences in terms of reproductive efficiency of the sow. The incidence of increased weaning to estrus intervals, postweaning anestrus, decreased farrowing rate and decreased litter size become more frequent the earlier sows are weaned. These potential disadvantages need to be weighed against the potential increase in the number of litters/sow/year and improved health and growth rate of the pigs produced. The objectives of this study were to determine the impact of two management practices: 1) weaning age and 2) lactation dietary crude protein level on sow feed intake, body weight change, backfat change, litter weaning weight, follicular development, uterine histology and hormone concentrations in the hypothalamus and pituitary.