Nutrient Recommendations -- We believe the nutrient recommendations in Tables 11, 12, 13, 14, 15 and 16 will result in a “bestcost” feeding strategy for most producers the majority of the time. However, certain conditions (i.e., specific genetic populations, economic, nutrient availability, nutrient profile and nutrient interactions) may require significant deviations from the recommendations presented. Also, the current debate surrounding the environmental consequences of nitrogen and phosphorus excretion was considered in the development of amino acid and phosphorus recommendations.
Although crude protein values still appear on feed labels and in some feeding recommendations, we did not list dietary protein recommendations because pigs do not require protein in their diet. Instead they require amino acids, which are found in protein. The recommended levels for the most critical amino acids are given in Tables 11, 12, 13, 14 and 15. Lysine is the first limiting amino acid in grain-soybean meal-based diets. In these diets, there is a strong relationship between the protein and the lysine level of the diet. For example, a corn or milo soybean meal-based diet containing .95% lysine will contain about 18% protein. A diet with .80% lysine will contain about 16% protein and a diet with .65% lysine has about 14% protein.
Health -- When pigs are exposed to antigens (substances foreign to the body), there may be fewer nutrients available for normal growth.
Management procedures such as segregated early weaning (SEW) or medicated early weaning (MEW) are being employed to reduce or eliminate the pig’s exposure to antigens. Presumably because of an improved health status, SEW or MEW pigs consume more feed, grow faster and require less feed per unit of gain from weaning to slaughter weight than do pigs weaned after about 21 days of age and kept in the vicinity of older pigs.
Feed intake -- Feed intake is used synonymously with feed disappearance from feeders or storage bins. Feed disappearance includes feed that is eaten and feed that is wasted or spilled and probably overestimates actual feed consumed. Certain processing methods (e.g., pelleting), feeder design and management practices reduce feed disappearance because feed wastage is reduced, but they may have little effect on feed intake. Other practices, such as liquid or paste feeding, may produce a real increase in feed consumption.
Water -- Water is one of the most important components of a feeding program for swine. Vital to all body functions, water accounts for as much as 80% of body weight in pigs at birth and declines to about 50% in market swine.
Feed Processing -- Processing feed is an important step between the nutritionist and the pig. No matter how precisely diets are formulated, pig performance will suffer if the diets are not processed and mixed properly. Critical components of feed preparation include particle size reduction and mixing efficiency.