There is conflicting evidence regarding their influence on rates of returns to service after mating and total-born litter size. Adding various forms of sugar such as molasses to lactation diets was found in some studies to result in larger subsequent litter sizes and more rapid returns to service after weaning. There is evidence that adding fiber to gestation diets may improve sow longevity, body weight loss during lactation, and the prevalence of stereotypical behavior. Calcium and phosphorus may influence the prevalence of reproductive failure by affecting sows, longevity.
Insufficient salt is associated with reduced litter sizes.
In sum, there is a great deal of research indicating that nutrient intake during lactation has substantial and multiple effects on the reproductive performance of sows after weaning. The diagnostician is not only faced with the problem of ruling out lactation nutrition as one of the several potential causes of reproductive failure but is also faced with the problem of determining which of several nutrients is the cause of suboptimal performance. Koketsu Y, Dial GD, Pettigrew JE, et al. The influence of nutrient intake on biological measures of breeding herd productivity. Swine Health Prod .