Methods of Supplying Nutrients -- Making sound decisions about the method(s) used to supply pigs nutrients is an important part of feed program design. However, the terminology used to describe the methods of supplying pigs nutrients often is confused.
There are four basic methods of supplying nutrients to pigs:
1) purchased complete feed;
2) grain plus concentrate or supplement;
3) grain plus soybean meal and basemix; or
4) grain, plus soybean meal, salt, calcium and phosphorus source(s) and premix.
Tools for Quantifying Performance -- We have provided nutrient recommendations based on fat-free lean growth rate, 21-day litter weight and feed intake in this publication. These factors influence the quantity of nutrients pigs require. By monitoring pig performance, it is possible to formulate diets to specific production situations and reduce the consequences of underfeeding or overfeeding nutrients. This section will describe tools to use in quantifying pig performance. The procedures involve feeding high nutrient dense diets to a sample of pigs to evaluate their performance when dietary nutrient density is not likely a limiting factor. Once the performance potential of the pigs is known, diets can be formulated.
Example Diets -- Example diets for all classes of swine are presented in Tables 19, 21, 22, 24 and 25. Ingredient analysis values in Table 29 were used to formulate the diets. Diets containing added fat were formulated to contain the same lysine:calorie ratio as diets without added fat. Fat reduces feed intake and unless the amino acid density is increased pig performance may be compromised due to a shortage of amino acids relative to calories. In general, these diets promote best-cost gain. Because ingredient price and availability are not constant, consider using alternate feedstuffs to optimize cost of gain. Refer to Tables 1 and 2 for guidelines when using alternate energy and protein sources.
Growing Pig Management -- Pigs undergo many physiological changes between weaning and market weight. The digestive system converts from one best suited to using milk to one suitable for the breakdown and absorption of complex carbohydrates and proteins found in grain and soybean meal. Daily feed intake normally increases steadily between weaning and market weight. Lean growth rate reaches a plateau when the pigs weigh about 130 lb and declines thereafter. These changes are the basis for the feeding recommendations listed for growing finishing pigs in this nutrition guide. Pigs should have ad libitum access to feeds reformulated to contain different ingredients and nutrient densities as they grow. This is commonly called "phase feeding." Phase feeding is essential to optimizing pig performance and controlling feed costs in a swine enterprise by limiting the time that nutrients are over- or underfed. In addition, phase feeding reduces the amount of nitrogen and phosphorus pigs excrete. Starting pigs weighing less than about 25 lb should be fed diets containing several specialty ingredients. Thereafter, switch them to grain-soybean meal-based diets containing few, if any, specialty ingredients. Reduce the nutrient density of the diet as pigs approach market weight.
Practical Applications and Outcomes.
The recommendations and concepts presented in this publication are intended to help pork producers apply appropriate nutrition-based technologies. These technologies are designed so that nutrition does not limit production potential and profitability in most situations. However, pigs must be capable of responding to improved nutrition. Weaknesses in the operation such as crowding, poor sanitation, inadequate ventilation, chronic disease, and lack of proper temperature control will limit the response to nutrition. Optimum nutrition can not substitute for good management practices but must be used to complement good management.