Amino acid nutrition of the lactating sow: the requirement for dietary lysine

Abstract

ABSTRACTThe lysine requirement of the lactating sow was examined in two Latin-square experiments using multiparous sows, in mid lactation, each of which suckled a litter of 10 piglets. The lysine requirement was examined by the addition of supplementary synthetic lysine to a basal diet deficient in lysine, to give dietary lysine levels of 6·4 to 17·2g/kg dry matter. The adequacy of the lysine supply was judged by the responses of plasma lysine, plasma and urea-nitrogen, urinary urea-nitrogen and milk composition. Intersecting linear regression lines were fitted to the treatment means. The responses of urinary urea-nitrogen, in the two experiments, indicated that the lactating sow required approximately 48·5 g dietary lysine per day while the response of plasma lysine indicated a requirement of approximately 51 g lysine per day. Plasma urea and milk composition were less useful as indicators of the nutritional adequacy than were urinary urea-nitrogen and plasma lysine.