Review: Nutrient requirements of the modern high-producing lactating sow, with an emphasis on amino acid requirements

Abstract

Sow productivity improvements continue to increase metabolic demands during lactation. During the peripartum period, energy requirements increase by 60%, and amino acid needs increase by 150%. As litter size has increased, research on peripartum sows has focused on increasing birth weight, shortening farrowing duration to reduce stillbirths and improving colostrum composition and yield. Dietary fibre can provide short-chain fatty acids to serve as an energy source for the uterus prior to farrowing; however, fat and glucose appear to be the main energy sources used by the uterus during farrowing. Colostrum immunoglobulin G concentration can be improved by increasing energy and amino acid availability prior to farrowing; however, the influence of nutrient intake on colostrum yield is unequivocal. As sows transition to the lactation period, nutrient requirements increase with milk production demands to support large, fast-growing litters. The adoption of automated feed delivery systems has increased feed supply and intake of lactating sows; however, sows still cannot consume enough feed to meet energy and amino acid requirements during lactation. Thus, sows typically catabolise body fat and protein to meet the needs for milk production. The addition of energy sources to lactation diets increases energy intake and energy output in milk, leading to a reduction in BW loss and an improvement in litter growth rate. The supply of dietary amino acids and CP close to the requirements improves milk protein output and reduces muscle protein mobilisation. The amino acid requirements of lactating sows are variable as a consequence of the dynamic body tissue mobilisation during lactation; however, lysine (Lys) is consistently the first-limiting amino acid. A regression equation using published data on Lys requirement of lactating sows predicted a requirement of 27 g/day of digestible Lys intake for each 1 kg of litter growth, and 13 g/day of Lys mobilisation from body protein reserves. Increases in dietary amino acids reduce protein catabolism, which historically leads to improvements in subsequent reproductive performance. Although the connection between lactation catabolism and subsequent reproduction remains a dogma, recent literature with high-producing sows is not as clear on this response. Many practical aspects of meeting the nutrient requirements of lactating sows have not changed. Sows with large litters should approach farrowing without excess fat reserves (e.g. <18 mm backfat thickness), be fed ad libitum from farrowing to weaning, be housed in a thermoneutral environment and have their skin wetted to remove excess heat when exposed to high temperatures.

Lysine (protein) requirements of lactating sows

“…This analysis is further validated by evaluating the combined data for the parity 4+ sow, which requires approximately 63 g of SID Lys/d when LGR is 2.7 kg/d. Both values would be slightly higher than that estimate of Boyd et al (1993) and slightly lower than that of the review conducted by Tokach et al (2019) , which indicates that sows require 27 g of SID Lys per day per kilogram of LGR without sow body weight catabolism to contributing to the Lys requirement.…”

Effects of Dietary Lysine Levels on Production Performance and Milk Composition of High-Producing Sows during Lactation

“…However, in our previous research, Lys levels (0.95% and 1.10%) over two consecutive lactations did not affect the average weight at weaning, litter weight at weaning, litter weight gain, and litter growth rate in multiparous sows [ 30 ]. A recent study that used a regression equation using published data on Lys requirement of lactating sows predicted a requirement of 27 g/day of digestible Lys intake for each 1 kg of litter growth, and 13 g/day of Lys mobilization from body protein reserves [ 4 ]. Therefore, increasing dietary Lys intake can reduce BW loss and body protein mobilization during lactation, especially younger parity sows.…”

“…The development of modern lactating sows has also resulted in animals with lessened body fat reserves and decreased appetite [ 2 , 3 ]. Therefore, sows need more nutrients to meet their lactation needs with a high litter size [ 4 ].…”

Meta-analysis of recommended digestible lysine levels for primiparous lactating sows

“…productivity has increased considerably in recent years, mainly owing to an increase in litter size, which has resulted in an increased metabolic demand for nutrients to support fetal growth and colostrum and milk production (TOKACH et al, 2019). However, this increase in nutritional requirements has not been accompanied by the pattern of sow intake, thus, sows undergo excessive mobilization of body protein during lactation (YANG et al, 2000a).…”