Optimizing nutrition of the gestating and lactating sow is dependent on several factors, including valid estimates of energy and amino acid requirements, knowledge of feed ingredient quality and nutrient availability, and feeding systems. Together, these factors are critical to ensure sow health, wellbeing and long-term productivity. Determinants of energy and amino acid requirements for gestation include body maintenance, growth of conceptus and changes in maternal energy and protein stores; for lactation, litter growth rate is by far the most important determinant. Energy requirement for these processes have been quantified and effective metabolizable energy requirements estimated. In contrast to net energy, effective metabolizable energy accounts for the effect of dietary energy source on energetic efficiencies. Amino acid requirements are now universally expressed on a standardized ileal digestible basis, which represents amino acid availability following small intestinal absorption, and accounts for basal endogenous amino acid losses. The main determinant of amino acid requirement for maintenance include the basal intestinal endogenous amino acid losses, which are related to the level of feed intake, and to the amino acid losses from skin and hair, which are a function of the sow's metabolic body size. For gestation, five protein pools together define the sow's global body protein pool, namely the maternal body, the fetal body, the uterus, the placenta and associated fluids, and the udder. The unique amino acid profiles (i.e. amino acid:lysine) for each of these pools and estimated efficiency of amino acid deposition are used to calculate a global standardized ileal digestible requirement for each amino acid for gestation. For lactation, the amino acid requirements are defined by the amino acid composition of two pools (maternal body and milk), the estimated efficiency of amino acid utilization and their relative contribution to protein accretion over the course of lactation. Ensuring that gestating and lactating sows receive the energy and amino acids needed to meet the expected productive demands (i.e. conceptus and litter growth, respectively) is dependent upon feed ingredient quality and gestation and lactation feeding systems. Optimal feeding systems which include feeder designs and feed delivery methods are those that optimize feed intake, reduce stereotypies and ensure wellbeing.
- Amino acid