Example Diets for Swine

The ability to properly formulate diets to achieve production goals and optimize profitability is essential for the success of any pork production operation. Swine diets are increasingly more complex with the emergence of improved nutritional technologies and greater availability and use of alternative feed ingredients. This factsheet is intended to teach key practical concepts and principles of swine nutrition and diet formulation through the presentation of diets made for various classes of swine.

Objectives

•  To demonstrate key concepts and principles of swine nutrition and diet formulation.
• To provide examples of practical diets that may be fed to pigs during various production phases.

Key Concepts and Principles Demonstrated

The key concepts and principles demonstrated in the factsheet are:

• The importance of formulating diets on a standardized ileal digestibility (SID) basis vs. total basis
• Amino acid balance
• The importance of formulating diets on an available phosphorus or digestible phosphorus basis vs. total basis
• Adjusting dietary nutrient concentration as dietary metabolizable energy (ME) density changes
• Phytase use in swine diets
• Use of alternative ingredients in swine diets

Process to Develop Diets

The National Swine Nutrition Guide (NSNG) Diet Formulation and Evaluation CD was used to develop the example diets used in this factsheet. Diets were formulated to meet or exceed SID lysine:ME (g/Mcal ME) and available phosphorus (% of the diet) recommendations using ingredient profiles and use rates presented in PIG Factsheet # 07-02-09 (NSNG Tables on Nutrient Recommendations, Ingredient Composition and Use Rates). All diets are corn and soybean meal-based, nutritionally adequate and contain common ingredients used in swine diets in the US.

All diets were formulated to demonstrate key concepts as stated previously with least cost formulation used when utilizing crystalline amino acids and phytase in applicable diet examples.

Also, all diets contain vitamin and trace mineral premixes at the suggested inclusion rates as recommended by PIG Factsheet # 07-02-06 (Trace Minerals and Vitamins for Swine Diets). While there are vitamins and trace minerals in grain and protein sources, additional quantities of several vitamins and trace minerals are required to be added in diets to ensure deficiencies do not occur.

In Tables 1 and 2, diet 1 is designated as a base diet to which various other feed ingredients are added. All the diets inTable 1 are formulated for a high lean gain line of swine (0.85 lb of lean per day) growing from 180 to 225 lb. Both diets inTable 2 are formulated for parity 2 gestating females. All diets contained within a table (Tables 1 and 2 only) are expected to produce similar pig performance.

Diet Examples

Diet 1 is a typical corn-soybean meal based diet. Corn and soybean meal are the sole sources of energy and amino acids in this diet, and also provide a portion of the pig’s requirement for calcium and phosphorus with monocalcium phosphate (an inorganic phosphorus source) and limestone included to provide the balance of the pig’s calcium and phosphorus requirements. Salt is included to provide sodium and chloride.

Diet 2 is the base diet with the inclusion of crystalline lysine (L-lysine HCl). Because some lysine is supplied by L-lysine HCl, less soybean meal is needed in this diet. However, diet 2 contains the same amount of SID lysine as diet 1, but less crude protein. Even though diet 2 contains less crude protein and soybean meal than diet 1, pig performance will be unaffected because the proper balance of amino acids has been maintained. This illustrates that pigs have a requirement for amino acids (lysine being the most limiting in practical diets) rather than crude protein.

Diet 3 is the base diet containing crystalline lysine, threonine (L-threonine) and methionine (DL-methionine). This diet contains significantly less soybean meal and crude protein (14.0 vs.17.3%) than diet 1, but the same amount of SID lysine and sufficient quantities of threonine, methionine and other amino acids to meet the pig’s requirements.Tryptophan is the next limiting amino acid but soybean meal rather than crystalline tryptophan is used as a more economical source to meet this requirement. Pigs fed diet 3 will excrete about 25% less nitrogen due to fewer excesses of amino acids in the diet. Diet 3 is considered more ideal in terms of amino acid balance than diet 1, because it contains concentrations of amino acids that are closer to the pig’s actual requirement.

Diet 4 is the base diet formulated to contain 400 lb/ton of corn distillers dried grains with solubles (DDGS). Note this diet contains the same amount of SID lysine as diet 1, but significantly more crude protein (20.2 vs. 17.3%). Diet 4 also contains more total lysine than diet 1 (0.94 vs. 0.90%). If diet 4 had been formulated on a total lysine basis to contain 0.90% total lysine, the amount of lysine available to the pig for growth would have been less than required, and consequently would likely reduce pig performance.This illustrates the importance of formulating diets on a SID basis rather than on a total basis. In addition, note the difference in the amount of monocalcium phosphate in diet 4 compared to diet 1 (5.6 vs.14.6 lb/ton). Use of DDGS in swine diets reduces the need for phosphorus supplementation, because the phosphorus in DDGS is significantly more available and digestible than that in corn.

Diet 5 is the base diet containing crystalline lysine and threonine and 400 lb of DDGS/ton of feed. This diet contains the least amount of soybean meal of any of the previous diets. Higher levels of crystalline lysine can be used in diets containing DDGS which further reduces the level of soybean meal in diets containing DDGS when formulating on a SID lysine basis. Thus, the crude protein content of diet 5 is considerably less than that of diet 4 which contains no crystalline amino acids (16.5 vs. 20.2%).

Diet 6 is the base diet plus phytase. Phytase improves the availability and digestibility of phosphorus from grain and soybean meal; therefore, significantly less monocalcium phosphate is required in the diet to meet the pig’s phosphorus requirement (5.0 vs. 14.6 lb/ton). Also, note that the amount of available phosphorus in diet 6 equals the amount (requirement) supplied by diet 1. However, the concentration of total phosphorus in the diet is significantly less in diet 6 vs. diet 1 (0.42 vs. 0.52%).This illustrates the importance of formulating diets on an available phosphorus basis rather than total. Pigs fed diet 6 will excrete approximately 19% less phosphorus than pigs fed diet 1 ((0.52% – 0.42%) divided by 0.52%). More details about phytase are presented in PIG # 07-03-04 (Feed Additives for Swine – Enzymes and Phytase).

Diet 7 is the base diet with the addition of crystalline lysine and phytase. This diet contains less soybean meal and monocalcium phosphate than diets 1 and 6.

Diet 8 is the base diet plus crystalline lysine and threonine (other crystalline amino acids are not needed or are not economical in least cost formulation), DDGS and phytase. This diet contains the least amount of soybean meal of all diets inTable 1 (218.6 lb/ton). Also, no inorganic phosphorus and less phytase are required than in diets 6 and 7, because of the greater phosphorus availability and digestibility of DDGS vs. that of corn. Note the low total phosphorus content in this diet compared to that of diet 1 (0.40 vs. 0.52%); yet the dietary concentrations of available and digestible phosphorus match those of diet 1.

Diet 9 is the base diet plus 3% added fat. Liquid fat sources can be added to growing and finishing diets as a means to increase growth rate and improve feed efficiency. A general rule is that daily gain will increase by 1% and feed efficiency will improve by 2% for every 1% added fat to the growing and finishing diets. This type of diet can be implemented if the economic return from improved growth and feed efficiency are greater than the increase in feed cost associated with this type of diet. This diet contains more soybean meal and SID lysine (as % of the diet) than diet 1, yet the amount of SID lysine per Mcal of ME is similar. Because feed intake is expected to decrease when fat is added to the diet, it is important to increase nutrient concentrations in the diet to maintain sufficient daily intake of nutrients. Therefore, a higher density of SID lysine (as % of the diet) and other nutrients is required. Formulating diets on a g/ Mcal of ME basis takes into account variations in the energy density of the diet. Diet 9 is the most energy dense of all the diets inTable 1 (1577 kcal/lb).

Table 2 The purpose of this table is to demonstrate the effect of adding a fibrous feedstuff to a sow gestation diet. Diet 1 is a typical corn-soybean meal diet for gestating sows. Diet 2 is the base diet containing soybean hulls to lower the diet energy level to 1350 kcal of ME/lb. Due to the lower energy density of diet 2 (1350 vs.1492 kcal/lb), it must be fed at a higher amount than diet 1 (4.7 vs. 4.2 lb/d) to provide the same daily ME intake (6.3 Mcal/d) in limit-fed gestating sows. Because a greater quantity of diet 2 is provided to meet the sow’s energy requirement, the dietary density of amino acids, calcium and phosphorus should be lower compared to diet 1, resulting in similar daily nutrient intakes. However, for total phosphorus and digestible phosphorus, the lower energy diet provides a lower daily intake then that provided by the base diet. This is due to differences in ingredient values for these two nutrients, as the diets were formulated for available phosphorus based on dietary energy level. Thus, specific nutrient variables not formulated to minimum or suggested specifications may not have the same daily nutrient intake.

Table 3 Example diets for a 4-phase nursery feeding program are shown in Table 3. Several specialty ingredients such as whey, plasma protein, fish meal, and blood cells are typically added to phase 1, 2 and 3 diets to improve feed intake of newly weaned pigs and provide sources of nutrients that are highly digestible which allow for a smooth transition to simpler corn-soybean meal based diets. For example, the amount of dried whey decreases from 625, to 500, to 200 lb/ton of feed in the Phase 1, 2, and 3 diets, respectively. Choice white grease or other sources of fat are added to increase diet energy density and enable diets to be pelleted while minimizing potential heat damage to the amino acids and/or lactose of specialty ingredients. Sources of zinc or copper can be added to provide pharmacological concentrations of those minerals which improve feed intake and growth performance.The phase 4 diet contains no specially ingredients and those similar to that normally included in growing and finishing diets. More details about the nutrition of nursery pigs are presented in PIG factsheet #07-01-08 (Nursery Swine Nutrient Recommendations and Feeding Management).

Table 4 Example diets for a 5-phase growing-finishing feeding program with and without feeding ractopamine are shown inTable 4.The addition of ractopamine hydrochloride (Paylean®) to the diet (phase 5 + RAC) increases lean gain, thereby increasing the daily requirement of amino acids, calcium and phosphorus from the diet. If feed intake is largely unchanged with addition of ractopamine, dietary concentration of these nutrients must increase in order to meet increased daily requirements. For example, the SID lysine level is increased by approximately 30% (0.69 vs. 0.90%) for pigs fed a diet containing ractopamine compared to pigs at the same weight (225-270 lb) not fed ractopamine. More details about the nutrition of growingfinishing pigs are presented in PIG factsheet #07-01-09 (Growing-Finishing Swine Nutrient Recommendations and Feeding Management).

Table 5 Example diets for parity 2 or greater gestating and lactating sows and breeding boars are shown inTable 5.The gestating sow and breeding boar diets are limit-fed to control energy intake, but the lactation diet is full-fed. The lactation diet contains crystalline lysine (0.9 lb/ton); valine is the next limiting amino acid in this diet. More details about the nutrition of gestating and lactating sows and breeding boars, respectively, are presented in the following PIG factsheets: #07-01-11 (Gestating Swine Nutrient Recommendations and Feeding Management); #07-01-12 (Lactating Swine Nutrient Recommendations and Feeding Management); and #07-01-13 (Breeding Boar Nutrient Recommendations and Feeding Management).

Summary

Proper nutrition plays an important role in achieving production goals and optimizing profitability in any pork production business. Swine diets are increasingly more complex due to the emergence of improved nutritional technologies and greater availability and use of alternative feed ingredients. Practical concepts and principles of swine nutrition and diet formulation critical to the development of a successful swine feeding program are detailed in this factsheet.