The influence of nutrient intake on biological measures of breeding herd productivity

YK, GDD, VLK:Department of Clinical and Population Sciences, College of Veterinary Medicine, 1988 Fitch Avenue, Room 385, St. Paul, Minnesota, 55108; JEP: Department of Animal Science, University of Minnesota, St. Paul, Minnesota, 55108 Summary: This review examines the influence of lactational feed and nutrient intake on common measures of breeding herd productivity: weaning-to-first-service interval, total pigs born per litter, the occurrence of reproductive failure, and percent preweaning mortality. Evidence suggests that inadequate intake of feed, protein, and energy are associated with prolonged weaning-to-first-service intervals. There is conflicting evidence regarding their influence on rates of returns to service after mating and total-born litter size. Adding fat to the diets of lactating sows is cited as having an inconsistent effect on weaning-to-first-service interval and a positive influence on preweaning mortality in those herds with persistently high mortality rates. 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. While being used prophylactically to alleviate constipation, fiber appears to have no beneficial effect on either subsequent litter size, weaning-to-first-service intervals, or preweaning mortality when added to lactation diets. 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. The vitamins biotin, folic acid, vitamin A/ß carotene, and vitamin E/selenium have been found in some studies to influence total-born and/or born-alive litter size by affecting ovulation, implantation, and/or embryonic survival rates. Rates of occurrence of reproductive failure, intervals from weaning to service, and preweaning mortality may be influenced by biotin and/or riboflavin. 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. he intake of several nutrients during the various phases of the reproductive cycle have been found to significantly influence reproductive and/or lactational performance. To optimize breeding herd performance and to efficiently and effectively troubleshoot reproductive problems, the diagnostician must understand the effects of nutrients on breeding female performance. This review critically examines the effects of nutrient intake during various phases of the reproductive cycle on sow lactational and reproductive performance; specifically, number of pigs weaned, litters per sow per year, and litter weaning weights and the parameters that comprise them. It is intended to bridge the gap between what is published in the scientific literature and situations commonly encountered by diagnosticians working with commercial breeding herds.