Conventional swine rations consist primarily of corn and soybean meal -- corn for energy and soybean meal for protein. However, diversified farmers may have other types of grains, crop residues, and forages that lack a ready market or are considered waste products. Pigs -- being versatile omnivores -- can eat a wide range of feeds, such as pasture grasses and other fibrous materials, as well as alternative energy and protein sources. The pig's ability to digest fibrous materials increases as it matures. Since they do not have rumens, pigs digest fiber primarily in their large intestine through fermentation. Jim Van Der Pol -- who grazes and direct-markets pork, chicken, and beef in Minnesota -- says in his "The pastured pig" series in Graze magazine:
Despite being single-stomached animals that often need some grain, hogs are wonderful pasture animals. Digestively, they are durable and flexible. They do not bloat, founder on grain, or ingest hardware. They eat weeds readily, even prefer them. If conditions get tough for the sward [grass-covered ground], they can be removed and switched immediately to a grain ration with no worries about digestive upset.
A three-year study by Auburn University's swine nutritionist Terry Prince proved that as much as two-thirds of a sow's feed needs can be satisfied by a well-managed pasture program, if vitamin and mineral supplements are provided.
A 2003 paper presented at the Third National Symposium on Alternative Feeds for Livestock and Poultry held at Kansas City, Missouri states:
Fibrous feeds traditionally have not been used for nonruminants due to their documented depression of diet digestibility in pigs and poultry. However, some types of fiber and fiber sources do not exert such negative effects on nutritional digestibility in older growing pigs and sows. Dietary fiber can have a positive effect on gut health, welfare, and reproductive performance of pigs. Hence, nutritionists are attempting to gain a more thorough understanding of dietary fiber in swine diets.
Colin Wilson, who farms with his father and brother Dan at Paullina, Iowa, has worked the bugs out of their pasture-farrowing system by trial and error the past 20 years. Wilson stresses that timeliness is critical, and that many jobs require two or even three people. They use a three-year rotation in three adjacent 18-acre fields. The rotation begins with corn, followed the next spring with a drilled mix of 3.5 bushels of oats, 10 pounds of alfalfa, and 3 pounds of orchardgrass. Oats are harvested, leaving a thick pasture cover for the hogs the following year. Colin explained that it took a long time to develop a successful pasture mix. He found that pastures with too little alfalfa were not as palatable to hogs, and that pastures with too much alfalfa did not produce a good orchardgrass stand and tended to be muddy in wet years.
Fencing the pasture is also important for the Wilsons' operation. As soon as possible in the spring, they string a two-wire (14-gauge) electric fence around the perimeter of the pasture; one wire is 4 to 8 inches high, and the other wire is 18 to 24 inches high. Each wire has its own charger, so there is always a hot wire if one charger malfunctions. This pasture is then divided into 150 by 300 foot pens, also using double wires. Wilson says it is not a good idea to charge the gates. If the gate is charged, the hogs learn not to pass that point, and then the producer will not be able to drive the hogs through the gate when it is open.
In addition to legumes and grass pastures, non-legume brassicas -- turnips, rape, kale, fodder beets, and mangels -- are high in protein, highly digestible, and make an excellent pig pasture.
Another option is the practice of having pigs self-harvest the grain, otherwise known as "hogging off" the crop. Some of the benefits of hogging off are that harvesting costs are eliminated, crop residues and manure are left on the land, and parasite and disease problems may be reduced. Many different crops can be used with this practice, as long as there are also legumes or brassicas available. Some examples of grains that can be self-harvested by hogs are wheat, rye, oats, dent corn, Grohoma sorghum, Spanish peanuts, and popcorn. Such direct harvesting can sometimes turn a profit from even a low-yielding grain crop.
In pastures available to hogs, inspect for weeds that can be poisonous to them, including pigweed, Jimson weed, two-leaf cockleburs, young lambsquarters, and nightshades. A couple of Web sites providing information and pictures of many poisonous plants are Colorado State University's Guide to Poisonous Plants and Spokane County Washington's Noxious Weed Control Board. Your veterinarian or county Extension agent should also be able to help with weed identification. The ATTRA publication Considerations in Organic Hog Production has additional information on using pastures for hog production.
If pastures are not available, feeding feedstuffs high in fiber is another possibility. Honeyman notes that studies show that fibrous feeds and protein by-products can make up as much as 90% of a gestating sow's rations, because of the sow's lower energy needs and large digestive tract. Acceptable feeds include alfalfa hay (need to feed good quality hay; moldy alfalfa can cause abortions), haylage (not more than 20% of a sow's ration), alfalfa and orchardgrass hay, grass silage, sunflower and soybean hulls, corn-cob meal, and beet pulp. Honeyman says even growing -- and finishing -- pig rations can be 10 to 30% forages, if energy levels are maintained.
Small grains can be used to reduce the amount of corn in swine rations. Wheat, triticale, barley, and hulless barley can totally replace corn, but need to be more coarsely processed than corn to reduce dust and flouring effects -- continuous feeding of finely ground grains can cause ulcers in pigs' gastrointestinal tract. The differing nutritional values of small grains means that the ration will have to be formulated to meet the hogs' energy and protein needs -- especially for the amino acids lysine, trytophan, threonine, and methionine, and the minerals calcium and phosphorus. Light and/or weedy small grains that would be discounted at the elevator can be fed to pigs with no difference in their performance. Barley and hulless barley need to be stored after harvest before feeding them to swine. In the publication Barley Production in Alberta: Harvesting on the Government of Alberta's Agriculture Rural Development Web site, it states:
Newly harvested barley, whether dry, or high moisture, should always be stored about four to six weeks before being fed to any class of livestock. This storage period is often called a sweat period. Serious losses in cattle, pigs and poultry have been attributed to feeding newly harvested grain. There is some evidence that certain compounds in the newly harvested grain may be toxic to livestock. In storage, such compounds undergo chemical changes that make them non-toxic. Processing newly harvested barley for feed apparently does not eliminate the problem of toxicity -- a rest or sweat period is necessary.
The following publications offer further information about feeding small grains to hogs.
Some other small grains to consider are oats, rye, flax, hulless or naked oats, and high-fat oats. All of these small grains can be used in varying amounts in hog rations, according to their unique characteristics and nutritional values. Newer varieties of rye are less susceptible to ergot contamination -- a fungal infection that can cause abortions -- than older varieties and can be used as up to 30% of the energy source.
Oats' feed value is only about 80% that of corn; it has high fiber content and can be used as 20% or more of the energy source. A 2002 study by Mark Honeyman, Sebblin Sullivan, and Wayne Roush at Iowa State University discusses changes in performance of market hogs in deep-bedded hooped barns with the addition of 20% and 40% oats to the diet. The study didn't find any reduction in daily gain, feed intake, feed efficiency, or other crucial factors for either level of oats in the ration.
Up to 5% flax can be added to hog rations to increase the omega-3 fatty acids in the pork and improve sow performance. In 1995, South Dakota State University researchers tested feeding flax in a corn-soybean meal ration during the final 25 days of finishing. The results showed that the omega-3 fatty acids had increased. However, a consumer taste panel could detect differences in the bacon in rations that contained more than 5% flax. University of Manitoba researchers replaced some of the soybean meal and tallow and added 5% flax to gestation and lactation sow rations. The study showed that the sows fed flax delivered more piglets at farrowing, that the piglets had heavier weaning rates, and that the sows lost less weight during lactation and rebred sooner.
Hulless or naked oats and high-fat oats are newer varieties with improved nutritional characteristics that make them good alternative feeds. Hulless oats can be used as the total energy source in swine rations; however, because of the limited cropping history and marketing opportunities, their yield potential and economic value are unknown in many areas and first should be tested in small quantities.
Several other alternative grains that can be used in hog rations are cull, unpopped popcorn and buckwheat. Popcorn has nearly the same nutritional value as yellow corn and can replace corn on an equal weight basis. If you happen to be in an area where cull popcorn is available, it can sometimes be less costly than corn.
Buckwheat can be used to replace about 25 to 50% of corn. Buckwheat has only 80% of the energy value of corn but is higher in fiber and can be planted later in the season as a substitute crop in emergencies. Buckwheat should not be used for nursery rations or for lactating sows, because of their higher energy requirements. Buckwheat should be limited to 25% replacement of corn for white pigs housed outside. Buckwheat contains a photosensitizing agent called fagopyrim that causes rashes on pigs' skin and intense itching when the pigs are exposed to sunlight. This condition is called fagopyrism or buckwheat poisoning.
A 2004 paper by Lee J. Johnson and Rebecca Morrison at the Alternative Swine Program of the West Central Research and Outreach Center in Morris, Minnesota, reported trying alternative ingredients -- barley, oats, buckwheat, field peas, and expelled soybean meal -- in the ration to help reduce the additional carcass fat in pigs raised in hoop shelters rather than confinement houses. The study shows that feeding a low-energy diet based on small grains slows the growth rate and marginally improves carcass leanness in hoop-sheltered hogs, but doesn't affect the eating quality of the pork.
Soybean meal can be replaced or reduced by the use of alternative protein sources. Canola meal, sunflower meal, cottonseed meal, linseed meal, or peanut meal may be available locally, depending on your location. These alternative meals can substitute for soybean meal, but they do have different amino acid ratios and mineral levels that need to be taken into consideration when balancing the rations. Cottonseed meal contains various levels of free gossypol -- a compound found in cottonseed that is toxic to hogs. The 2003 Oklahoma Cooperative Extension publication Gossypol Toxicity in Livestock, by Sandra Morgan, provides specific information on gossypol toxicity levels for swine and other livestock.
Roasting or extruding whole soybeans is another option; the heat breaks down the trypsin inhibitors found in raw soybeans. Processed, green, frost-damaged beans that would be discounted at the elevator can be used in the ration without any problems. The higher oil content of whole, processed soybeans produces a faster rate of gain than soybean meal. The cost of processing equipment and the fact that the extruded and roasted products don't store well are considerations that the producer has to take into account. Additional information on feeding soybeans to hogs is available at http://www.omafra.gov.on.ca/english/livestock/swine/facts/green-soybeanspigs.htm.
Sweet white lupines can make up to about 10% of the ration for most finishing and gestating animals. Lupines' protein content can vary from 25 to 38%, and they have about half the lysine of soybeans. Lupines should be supplemented with iron at 400 parts/million and methionine.
Field peas are another option. The South Dakota State University publication Using South Dakota Grown Field Peas in Swine Diets states:
Field peas are a good source of energy and amino acids for swine. However, variety differences exist, and producers must know the nutrient content of the peas they are working with to properly formulate them into swine diets. Field peas are a good source of lysine, but the concentrations of methionine, tryptophan, and threonine must be watched closely. While peas can contain anti-nutritional factors, they are usually in such low concentration that field peas can be fed raw.
The publication is available at http://pubstorage.sdstate.edu/AgBio_Publications/articles/ExEx2041.pdf or by calling the Agriculture & Biological Science (ABS) Bulletin Room at 605-688-5628 or 800-301-9293.
Mung beans can be used as an alternative to soybean meal. Mung beans contain from 24 to 30% crude protein, but about equivalent lysine levels as a percentage of protein. Mung beans contain a trypsin inhibitor just like raw soybeans. This limits mung bean use in swine rations to about 10% for growing pigs, 15% for finishing pigs, and 10% for sow rations, unless the mung beans are heat-treated like whole soybeans.
The Oklahoma State University Extension publication Using Mung Beans in Swine Diets is available by calling the University Mailing Services at 405-744-5385.
It is important to remember that any changes to your rations, including adding alternative feedstuffs, may change the growth rate of the hogs. It is best to determine the feed-cost savings and any changes in market patterns before making any changes to your feeding program. Always assess any changes to your rations so that all the pigs' nutritional requirements are being met at every stage of growth. Alternative feeds have varying food values, so it is important to know the nutritional contents of each feed ingredient. Nutrient testing of alternative feed ingredients will eliminate any guesswork.