Protein nutrition of gestating sows

Dietary amino acid requirements of gestating sows vary depending on genetic strain, energy intake, body weight, and other factors. Estimation of amino acid requirements for gestating sows in a defined situation should be directed toward achieving a high rate of protein accretion and a modest rate of fat accretion. More information is needed to set target accretion rates precisely. A simple mathematical model was developed with the limited objectives of 1) aiding in understanding the interactions among energy intake, amino acid intake, protein accretion potential, and body weight in affecting the amount of body protein and fat accreted by pregnant sows and 2) providing general guidelines for feeding programs. Predictions from the model suggest that the daily lysine requirement varies markedly with variation in ME intake but that the requirement as a percentage of the diet is more stable as ME intake varies. At moderate ME intake, the lysine requirement seems greater during late gestation than earlier. The lysine requirement of heavy sows is less than that of light gilts at a similar ME intake, and this offers opportunity for modest cost savings in pork production. A compromise is necessary between the goals of a high rate of protein accretion and a modest rate of fat accretion. It seems that a sow's potential protein accretion rate is rarely limiting.