Amino Acid Needs of Lactating Sows

University of Illinois researchers conduced three experiments to evaluate the order of limiting amino acids in a corn-soybean meal diet for lactating sows experiencing high body weight loss during lactation. A reference corn-soybean meal diet containing 17.2% crude protein, 0.90% lysine, 0.65% threonine, 0.82% valine and 0.28% methionine was diluted with cornstarch, sucrose and soybean oil to provide a lysine level of 0.51% while keeping the ration of corn to soybean meal constant. Synthetic amino acids were added to the basal diet to provide needed amino acid levels and combinations. Preliminary results indicated that plasma urea nitrogen was sensitive to amino acid levels when the diets were fed for a four-day feeding period. Results indicated that lysine was first limiting and threonine was second limited in the experimental diets. These results become increasingly important as the availability of low-lysine feed ingredients become more plentiful.

Soltwedel, K.T., R.A. Easter and J.E. Pettigrew. 2006. Evaluation of the order of limitation of lysine, threonine and valine, as determined by plasma urea nitrogen, in corn-soybean meal diets of lactating sows with high body weight loss. J. Animal Sci. 84(7): 1734-1741.