Each stage of production has special nutritional needs and problems. These needs and problems must be considered when developing an economical feeding program.
Feed management for the developing replacement gilt must prepare the gilt for five to seven parities of production. They must be fed to encourage the growth of the skeleton, muscles, and general body size and to stimulate sexual maturity at an early age.
Select replacement gilts as early as possible (200 to 220 pounds) and hand feed to insure proper condition. Excessive fat or finish is wasteful and will lead to lowered reproductive performance. Extremely lean gilts may have trouble maintaining adequate condition during lactation. Generally, 5 to 7 pounds of a growing diet will provide adequate nutrients.
Gilts selected from high-producing sow lines may need the vitamin and mineral fortification of a lactation diet. A diet specifically for gilt development should be fed in this case. It should contain 0.80 percent lysine, 16 percent protein, 0.90 percent calcium, 0.75 percent phosphorus, and the vitamin and trace minerals listed for lactating sows in Table 2.
Breeding gilts that are too small (under 250 pounds) and in poor body condition will often lead to rebreeding problems after weaning. Flushing gilts (at least 6 to 8 pounds of feed per head per day) before breeding may improve litter size; however, feed intake must be reduced to about 4 pounds per head per day as breeding begins.
Most open sows have recently been weaned or have failed to conceive in a previous breeding period. Feed levels for these open sows should control body condition but put them in a weight-gaining situation at breeding time. Open sows should receive 4 to 6 pounds of a quality gestation diet per day while in the breeding area. Extremely thin sows may require more feed to enhance rebreeding.
If many sows become extremely thin because of heavy milk production, consider ways to increase feed intake during lactation. More frequent feeding or adding palatable ingredients to the diet may help. Adding fat to the lactation diet may also increase energy consumption. If a sow does not cycle or rebreed, consider culling the sow. Don't allow the sow to become fat in the breeding pen.
No special diet ingredients are necessary for breeding females. Adequate amounts of protein, calcium, phosphorus, and vitamins are important for breeding success. Do not use moldy feedstuffs in diets for breeding females! Hormones, aflatoxins, or other toxic substances produced by certain molds can drastically reduce reproduction in the sow.
Mature bred sows require little more than a maintenance diet during the first 90 days of gestation. During the last 20 to 25 days of gestation, rapid growth of the developing litter demands extra nutrients. Gestation weight gain for mature sows need not be more than 30 to 60 pounds (80 to 110 pounds including the products of conception). Some producers prefer to maintain a constant daily feed allowance throughout gestation. Others increase feed amounts as gestation progresses. Research shows that either method can be successful if the total gestation feed allowance supplies adequate nutrients.
Bred gilts require feed nutrients for maintenance, growth of the developing litter, and additional body growth of the gilt herself. Assuming proper body condition at breeding, gilts should gain about 75 pounds during the first gestation. When possible, a special gestation diet for gilts from high-producing lines may improve longevity. Research has shown advantages to increasing the protein level to 16 percent for gilts. Inadequate nutrition at this time frequently leads to problems in rebreeding the first-litter sows.
The amount of feed intake during gestation depends on the type of housing, the energy concentration of the diet, and the season of the year. Typical corn-soybean meal diets fed at 4 pounds per head per day will supply adequate energy to maintain the average sow in acceptable body condition. Diets containing higher fiber levels (including oats, barley, alfalfa, etc.) may be required in higher amounts.
Sows kept in group pens or individual stalls get less exercise and are generally not exposed to as much cold weather as sows kept on pasture or in outside lots. Therefore, the bred sow requires less feed energy when confined. Total feed intake may vary from 3 to 4 pounds per day for individually-penned sows in summer to 6 pounds for sows in outside lots during winter.
The adequacy of feed intake during the reproductive cycle of a sow can be evaluated by the degree of condition or body fat levels. Condition can be measured as backfat, fatness over the hook or hitch bone, and general body shape. Sows that have 0.7 inches of fat at the last rib probably have adequate condition to enter a normal lactation period if a sufficient lactation diet is consumed. Also, the hook bones or point of the hip can be felt with the fingertips to estimate condition. This bone can barely be felt if the desired level of finish is covering it. The sow's body as viewed from the rear should show a general oval shape.
A sow's daily feed intake during gestation varies widely according to the factors discussed earlier. Therefore, the concentrations of protein, minerals, and vitamins also vary in order to supply the sow's daily needs. For example, a sow receiving 6 pounds of feed per day would only require a calcium level of 0.60 percent to supply the 16.3 grams of calcium needed daily. But a sow fed 3.5 pounds daily would require 1.03 percent calcium in the diet.
Fat, added to sow diets during the final 7 to 10 days before farrowing, may increase the survival of baby pigs shortly after farrowing. If the survival rate of pigs born alive is under 85 percent, adding 80 to 100 pounds of fat per ton of sow diet may provide an economical boost to litter size and weight at weaning. Increasing total intake of a standard sow diet during this period may also improve survival.
The farrowing house diet should provide increased nutrients for milk production, prevent constipation and prevent excessive weight losses. From gestation to full lactation, the sow's total energy requirements may double or triple. Although the sow can use nutrients stored in her body to produce milk, inadequate feed intake will often result in lowered milk production; smaller, weaker pigs; and rebreeding problems.
A sow must consume at least 10 to 14 pounds of a standard lactation diet daily (14,000 to 19,000 kcal of metabolizable energy) to maintain adequate milk production and body condition. Sows with large litters (10 pigs or more) may require as much as 16 to 18 pounds and peak intake may be over 20 pounds per day. If you use a self-feeder in the farrowing crate, try to identify sows that do not consume adequate amounts of feed. Low consumption levels may suggest sickness, constipation, or heat stress in the sow.
If lactation problems occur in sows fed with self-feeders (on full feed), implement a program of limited feeding. Instead of filling the feeder on the day after farrowing, hand-feed the sows 4 to 5 pounds the first day, then gradually increase by 1 to 2 pounds daily.
Excessive weight losses in sows and gilts may lead to slow returns to heat, nonreturns, or poor conception rates following weaning. These problems are more common when high-fiber diets are used, during long lactation periods, or in first-litter gilts or heavily-milking sows. Check feed intake levels, estimate daily nutrient intake, and correct feeding shortages. More frequent feeding, reduced bulkiness, or fat addition may be necessary to prevent excessive weight losses and meet daily nutrient needs.
Constipation occurs in many sows farrowed today and often goes undetected. This reduction in feed passage results in lowered feed intake and, therefore, reduced milk production. A laxative effect may be exerted by feed ingredients containing fiber, fat, or certain minerals.
Bulky fibrous feedstuffs exert a mild laxative effect on the sow. Wheat bran (added at 10 to 25 percent of the diet), oats, barley, beet pulp, linseed meal, and alfalfa meal will decrease constipation problems. However, these bulky feedstuffs lower the energy concentration of the ration, which may limit milk production. Fiber will also increase the heat of digestion in the sow, adding to heat-stress problems in summer.
Proper use of mineral laxatives in lactation diets will prevent constipation with little reduction of the diet energy concentration. Potassium chloride at 15 pounds per ton is an economical, effective laxative that can be safely fed through 4 weeks of lactation. Epsom salts (magnesium sulfate) at 20 pounds per ton is a good alternative.
A practical goal for feeding nursing pigs is to make maximum use of milk, yet teach young pigs how to eat food. A heavily milking sow will provide essentially all the nutrients (except iron) needed for excellent pig growth up to 3 weeks of age (see Figure 1). At that point, the sow's milk production levels off or begins to decrease and the pig's needs continue to increase. After 3 weeks of age, pigs need additional creep feed intake to insure adequate weaning weights and post-weaning growth.
Traditionally, creep feed was offered at 2 to 3 weeks of age. On many farms today, pigs are weaned at 18 to 21 days of age. Age at weaning will determine the age when creep feed should be offered and the quality of the creep diet. Pigs that are eating a dry feed prior to weaning are less affected by the weaning process.
Creep feed consumption depends on the palatability of the diet. Use every possible means to keep the creep feed fresh. Buy or mix creep diets often and feed in small, shallow trays two or more times a day. Large-capacity self-feeders are difficult to manage and should be avoided for pigs less than 4 weeks of age.
The creep diet may be a 24-percent crude protein prestarter or a lower-cost, 20-percent starter. The ingredient and nutrient composition of the diet depends on the weight and age of the pig. Most of the energy and protein should come from animal products (milk, whey, Menhaden fish meal, porcine plasma protein, some spray dried blood meals). Other ingredients may also improve intake: small amounts of sugar (15 pounds per ton), rolled oat groats, bakery by-products, and flavors. The physical form or texture of the creep diet affects acceptability to the baby pig. Hard, large-size pellets or dusty meal-type diets are usually not eaten as well as small, soft-pelleted or crumble-textured feeds.
The decision to purchase the prestarter and starter diets or mix them on the farm depends primarily on your ability to prepare the feed, as well as comparative costs, desired quality of end products, and availability of ingredients. These diets are relatively expensive on a weight basis, but the volume used should be small compared to other diets. An important profit opportunity lies in proper use of creep diets. A poorly mixed meal diet will reduce profits, where a more expensive commercial diet may improve profits.
Nursery pigs are frequently hampered by inadequate housing, sanitation, and nutrition. Under these conditions, the pigs may go through a period of little or no growth for 7 to 14 days after weaning (post-weaning lag). With proper nutrition, the setback suffered by the pigs can be eliminated.
Good nutritional management includes feeding a diet containing high-quality, highly palatable ingredients with the proper nutrient levels and proper feeding methods. The type of diet required depends on the age and weight at weaning. The younger or smaller the pig at weaning, the more critical the diet becomes. Dried whole whey, dried milk (whole, skim, or buttermilk), porcine plasma protein (1 to 6 percent), selected spray dried blood meals (2 to 4 percent, in combination with plasma proteins), fish meal, and oat groats are digestible sources of important nutrients. These ingredients are more important in the diets of pigs weaned at 20 days of age or less than 15 pounds. Diets for pigs weaned at 21 to 28 days or weighing 15 to 20 pounds should contain 5 to 25 percent of milk products and possibly some of the animal protein products. Pigs weaned at 35 days or more only need this type of diet for 3 to 5 days after weaning. Other ingredients, such as organic acids, bentonite, fat, vitamin C, etc., may be justified sometimes to improve performance at weaning.
If pigs have learned to eat a creep diet before weaning, using that same diet in the nursery will encourage the pig to eat and will reduce the post-weaning lag. Pigs weaned at an early age tend to feed all at once, just as they nursed the sow. Provide adequate feed trough space (4 inches per pig or two pigs per hole). Start pigs out on a slightly limited feed supply and gradually increase feed intake for the first 3 to 5 days in the nursery.
With proper nutrition, the effect of inadequate housing and management can be partially overcome.
This phase of production feed consumption stage and offers the greatest opportunity for improving feed efficiency and savings. The major feeding decisions involve selecting the most economical energy sources and matching nutrient content with actual feed intake and genetic potential for lean growth. The goal is to reduce feed costs per pound of gain while maintaining rapid daily gains and acceptable carcass quality.
The growing-finishing pig can be fed alternate energy sources such as grain sorghum, barley, wheat, triticale, fat, and a variety of by-product feedstuffs. Decisions to change diets from the standard corn-soybean meal-based feeds depend on comparative costs of gain, availability of alternate feeds, effects on carcass quality, and special feed handling considerations. The growing-finishing pig can quickly adapt to new feedstuffs with a minimum setback.
The addition of fat to grower-finisher diets depends on the relative costs of fat and grain plus other factors such as fat-handling problems and environmental temperatures. Fat added to the diet increases the energy concentration (kcal. per pound). Pigs on full feed will eat to meet their energy requirement. Adding fat reduces the pounds of feed consumed per day. Therefore, the concentrations of protein (amino acids), minerals, and other nutrients should be increased in proportion to the energy. Adding fat to the diet should improve feed conversion but may also increase backfat. Increasing the levels of other nutrients proportionally may also improve pig gains and can result in lower back-fat. Adding fat is especially important during periods of high temperatures when feed intake and therefore gain are normally reduced. Increasing the energy density of the diet by adding fat allows growing-finishing pigs to consume adequate energy though they are eating less feed.
Increasing the protein in the diet reduces feed required per pound of gain. However, the cost of gain will begin to increase. Decreasing the protein (lysine) below required levels reduces rate of gain and carcass muscle development while increasing feed required per pound of gain.
The amino acid requirements for growing-finishing pigs are under considerable
debate. It is clear that pigs with higher average daily lean gains (over
0.80 pounds per day) require more lysine per day. The recommendations in
Table 1 are based on average lean gain (0.6 to 0.8 pounds per day). At 60
to 80 pounds, the amino acid requirements for barrows and gilts begin to
separate. With average genetics, keeping gilts on a diet formulated for
pigs from 80 to 120 pounds will result in faster gains, lower backfat, and
improved carcass value. To properly formulate a diet for pigs from 40 pounds
to market, you need to know the genetics, daily feeding intake, sex, environment,
weight, and age of pigs you are feeding.