Chapter 14 Feeding swine.
The nutritional phases in the swine production cycle, illustrated in Figure 14-1, include:
Sow: lactation, breeding, gestation
Pig: suckling/creep feed, nursery, grower, finisher
A sample growth rate is plotted in Figure 14-2.
[FIGURE 14-1 OMITTED]
[FIGURE 14-2 OMITTED]
The lactating sow has the highest nutrient requirements of any type of swine. Within a few days of farrowing, the sow should be given free-choice access to a high-energy diet. The lactating sow will generally eat an amount of feed equal to 5 lb. plus 1 lb. for each pig she is nursing. Even when properly fed, the sow will probably not be able to consume enough energy to meet the needs of lactation, and will therefore lose weight. Sows are capable of producing about 20 lb. daily of milk that is the most nutrient-dense of all domesticated animals (Table 14-1).
As with all livestock, swine have the ability to store some nutrients during periods of excess intake. At times when nutrient use exceeds intake, these nutrient stores may be withdrawn to help maintain health and performance. During lactation, for example, nutrient use will often exceed intake for several nutrients. Calcium may be withdrawn from reserves in bone and made available for use in milk production (Giesemann, Lewis, Miller, & Akhter, 1998). Body fat and body protein may be mobilized to help supply the energy and amino acids used in lactation (McNamara & Pettigrew, 2002). Lactating sows deficient in these nutrients for short periods can maintain normal performance by mobilizing nutrient reserves, but a deficiency throughout lactation will result in reduced performance and health.
Livestock have little or no ability to store most other nutrients, so will require daily intakes in order to maintain health and performance. Diets inadequate in these nutrients will soon result in poor performance and symptoms of deficiency. Sows fed inadequate lysine during lactation, for example, may have a prolonged weaning-to-estrus interval (Yang, Pettigrew, Johnson, Shurson, Wheaton, White, Koketsu, Sower, & Rathmacher, 2000).
The milk of swine has considerably higher nutrient density than milk from other species (Table 14-1). However, the sow's milk does not contain an adequate amount of iron for the nursing piglet. Iron is not efficiently transferred to the milk, so manipulation of the sow's diet will not markedly affect the iron content of the milk. For this reason, and the fact that iron is not transferred to the fetal piglet in adequate amounts, the neonatal piglet should receive supplemental iron via intramuscular injection.
The structure of the sow's placenta is described as epitheliolchorial. This type of placenta does not allow antibody immunoglobulins to pass from the sow into the blood of the fetal piglets. The newborn piglet, therefore, has no antibody-mediated immunity to pathogens in the environment. By ingesting colostrum as soon as possible after birth, the neonatal pig acquires passive immunity from the antibody immunoglobulins in the colostrum.
The most critical nutrient for the lactating sow is energy, and these animals will generally eat to meet their requirement for energy. A sow that farrows with excess body condition will draw on the energy she has in storage to meet the energy demands of milk production, but energy from body fat is used much less efficiently than energy from the organic compounds in ingested feed. This means fat sows will have an impact on farm profitability even if they are able to perform well during the lactation.
The nutrient needs of boars, gestating sows, and sows to be bred are similar. In practice, swine farms generally use feed from the same bin for these three types of hogs.
Replacement breeding animals are usually selected from the animals raised for market within a month of marketing or at 5 to 6 months of age. Up until this time, growing animals have been fed free choice. The replacement animals are removed from the market hogs and managed separately. Their diet will be limit fed (about six lb. daily or 70 percent of full feed) to achieve breeding weight (260 to 300 lb.) at 7 to 8 months of age. Replacement gilts are usually bred after two or three estrous cycles. In practice, the diet used for replacement boars and gilts is often also the boar/gestation/breeding diet.
Most sows will come into heat within about 3 to 8 days after their pigs are weaned and may be bred at this time. However, nutritional and management factors can affect the length of the weaning-to-estrus interval. Sows that do not eat well during their lactation or are fed diets that are deficient in energy or protein may have a weaning-to-estrus interval that is longer than 8 days. Such nutritional deficiencies disrupt the normal production of reproductive hormones and cyclic function after weaning is impaired. Segregated early weaning may also result in a lengthened weaning-to-estrus interval.
Flushing is a practice whereby gilts or sows are fed an enhanced diet 2 weeks prior to and through the breeding period. The enhancement may be a greater amount of the previous diet or it may be a more nutrient-dense diet. Flushing may result in increased eggs ovulated and increased litter size. Flushing will probably be beneficial to gilts and sows that come into the breeding period in thin condition, and will probably not be beneficial to gilts and sows that are in good condition. Flushing may do more harm than good when practiced on overweight gilts and sows.
The productive life of animals in the breeding herd is dependent on management of body condition. If boars and sows are allowed to become fat, their libido will be impaired and it may be difficult to get them bred. Likewise, thin animals may not cycle properly until they receive adequate nutrition.
Nutrients ingested by the gestating sow are used for three functions: to maintain the sow, to accrete mammary tissue in late gestation, and to provide for development of the fetuses. The swine NRC software and the companion application to this text present a single requirement value for each nutrient that is the sum of what both the sow and her fetuses need.
A major challenge on many swine farms is to keep sows from getting too fat. This is because sow weight generally increases from parity to parity according to the following general pattern: gestation weight gain, 80 lb.; farrowing weight loss, 40 lb.; lactation weight loss, 25 lb. The result is a predicted weight gain of 15 lb. with each succeeding litter. The formulas in the companion application to this text predict sow weight change during gestation based on diet consumed. To manage gestation weight gain, sows should be limit fed 3 to 5 lb., depending on the energy density of the diet. An alternative to limit feeding is to use time restricted meal feeding or interval feeding. In this type of feeding management, animals receive free-choice access to feed for 2 to 6 hours only every third day.
To help prevent constipation in the lactating sow, it is advisable to increase the bulk in the diet of the late-gestation sow. Feedstuffs such as wheat bran, oat grain, dehydrated alfalfa, and beet pulp can be used in place of a portion of the corn grain in the diet. This high-bulk diet should be fed starting a few days before farrowing until a few days after farrowing.
The Suckling Piglet
With the exception of iron, the sow's milk provides a balanced diet for the suckling piglet. As noted earlier, an iron injection should be given to the piglet shortly after birth to prevent the neonate from becoming anemic. Nutritional anemia results when an iron deficiency leads to inadequate hemoglobin synthesis. The anemic pig becomes pale and weak. The neonatal pig is not going to receive adequate iron through the diet because its only ingredient--the sow's milk--is inadequate in iron content. Supplementing the lactating sow's diet with iron does not affect the milk's iron content. The neonatal pig, therefore, must receive an intramuscular injection of an iron-carbohydrate complex such as iron dextran. A single injection of 150 mg or 2 cc of iron dextran given at 1 to 3 days of age is usually adequate to prevent anemia. Some producers will give a second iron injection at 3 weeks of age.
The structure of the sow placenta is such that the large antibodies circulating in the sow's blood are not able to cross into the blood of the developing fetuses. As a result, pigs are born with no antibody-mediated defense against environmental pathogens. The sow's first milk (colostrum) contains the antibodies from the sow's blood, and pigs receiving colostrum will be protected from the diseases to which the sow has become immune until the pig is able to make its own antibodies at about 3 to 4 weeks of age. Obviously, it is important that the neonatal pig receive colostrum as soon as possible after birth in order to receive protection. The fact that the piglet's gut is only capable of absorbing intact antibodies for a short period of time makes it even more urgent that colostrum be ingested promptly. Although it is possible that some antibody absorption takes place as late as 3 days after birth, antibody absorption is maximal at birth and declines soon thereafter.
To achieve maximum growth rate and to facilitate a successful weaning, piglets should be given access to a "creep feed," or prestarter at about 1 week of age. Creep feed is feed that is intended solely for the consumption of the suckling piglet. As such, it should be placed in a location that restricts access to only the piglets. The most important characteristic of creep feed is that it be palatable. A palatable creep feed will ensure that the piglets will consume enough solid feed to make a smooth transition to the feed available after weaning. Palatability is enhanced by the fact that creep feed is usually produced as a crumble, and its formula usually includes dried skim milk, molasses, sucrose, and/or fat. Unless the producer is weaning pigs at less than 2 weeks of age, creep feed will be the most expensive feed on the hog farm.
Traditionally, pigs have been weaned at between 3 to 4 weeks. A practice called segregated early weaning (SEW) involves weaning pigs much earlier. SEW takes advantage of the fact that pigs are temporarily protected from environmental pathogens after intake of sow colostrum. These protected pigs are removed from the sow barn and placed in an environment that does not contain pathogens (they are segregated). SEW pigs should never have to use feed nutrients to mount their own immune response. When compared to pigs weaned at 3 to 4 weeks, SEW pigs are healthier, and because their immune system is not stimulated by pathogens, they convert feed to pork more efficiently. The disadvantage to SEW is that it requires more intensive management. The advantages of early weaning have been summarized by Veum (1991).
The Nursery Pig
Pigs will wean themselves at 6 to 8 weeks of age. Early weaning is generally considered to be weaning at an age of less than 4 weeks. Segregated early weaning involves weaning shortly after the piglet has received its colostrum from the sow, as early as 5 days of age. Early weaning requires intensive nutritional management and it may require special equipment capable of handling liquid feeds.
The Growing Hog
In farrow-to-finish swine farms, growing pigs are usually fed three different diets: the nursery diet (weaning to about 40-lb. body weight), the grower diet (40-to about 110-lb. body weight), and the finisher diet (about 110 to 250 lb.). Feeder pig producing farms will sell pigs leaving the nursery at 40 lb. to feeder pig finishing operations. Feeder pig finishing operations will purchase 40-lb. pigs and feed them through finishing.
To achieve maximum gain, pigs in these facilities should be on full feed (they should receive feed free choice) and a primary goal of management should be to maximize feed/dry matter intake. Pigs of high-quality genotype that have high intakes of balanced rations will respond with maximum lean gains and will be ready for market at the earliest possible time.
Beginning at about 66 lb. body weight, the nutritional requirements of barrows and gilts begin to differ (NRC, 1998). Barrows will consume more feed than gilts. Also, because the carcass of gilts will have a higher lean content than the carcass of barrows, gilts have a higher requirement for dietary protein (percentage) than barrows. In practice, gilts and barrows are not fed separately, so the swine NRC software and the companion application to this text give requirement values that are prorated based on the numbers and types of animals penned together.
The Finishing Hog
Finishing hogs will be fed on both farrow-to-finish and feeder pig finishing operations. The concentration of nutrients in the ration for the finishing hogs will be lower than that for the growing hogs, but the dry matter/feed intake per hog in the finishing group will be second only to the dry matter/feed intake of the lactating sow. Sixty percent of the cost of pork production is due to feed purchases, and because of both the high intake per animal and the large number of animals, the finishing hogs will consume the largest tonnage of feed at the farrow-to-finish farm. Energy feedstuffs are the largest component of the finishing hogs' diet. Corn grain is usually the most economical energy feedstuff fed to hogs in the Americas.
Finisher hogs should be managed to achieve maximum dry matter/feed intake. If, for example, feeder space is suboptimal, some animals in the group may not consume maximally. This will result in increased variation of body weight within the group. In those pork-production systems in which an entire group of hogs is marketed at the same time, this variation in body weight may result in a financial penalty.
Carcass quality can be affected by substituting high-fiber concentrates for a portion of the corn in finishing diets. Such diets may produce a leaner carcass at the expense of feed efficiency and rate of gain. The optimal feed formulation for the finishing hogs will be determined by the added value of a leaner carcass as compared to the expenses associated with the price of high-fiber feedstuffs and longer days to market.
Finishing hogs are poor masticators of feed (Allee, 1983). For this reason, these animals show poor utilization of diets that contain unprocessed grains. Although young pigs are apparently better chewers than are finishing hogs, grinding of the cereal grain for either age improves feed efficiency.
Hogs are generally shipped to market at 250-lb. body weight. Feed conversion by swine from 40 lb. to market weight is generally 3 to 4 lb. of feed per pound of gain.
SWINE FEEDING AND NUTRITION ISSUES
Nutrient Supplementation in Swine Nutrition
Microbes in the digestive tract of all livestock use low-quality protein and non-protein sources of nitrogen in ingested feed to build high-quality protein in microbial cells. Ruminant animals are able to digest these microbial cells because the site of microbial production (the rumen) is upstream from the primary site of absorption (the small intestine). Most microbial production in the digestive tract of swine takes place in the large intestine, downstream from the primary site of absorption. Therefore, the pig must be fed high-quality sources of protein. High-quality protein sources are those that not only contain all the amino acids found in pork, but contain these amino acids in proportions that are similar to those found in pork.
Microbes in the digestive tract also produce the B vitamins. Again, in the pig, these nutrients are synthesized downstream from the primary site of absorption so the pig does not have access to these vitamins unless it is allowed access to its manure. In addition, the usual energy and protein sources fed to swine contain low concentrations of the B vitamins. For these reasons, swine diets are usually fortified with the B vitamins.
Unlike the B vitamins, there is no mineral synthesis taking place in the digestive tract of livestock. In terms of the need for mineral supplementation of swine diets, if there is inadequate bioavailable mineral in the energy and protein sources chosen, a supplemental source of mineral will need to be added.
The Energy Requirement
In the swine NRC (1998) and the companion application to this text, the energy requirement is calculated based on information describing the pig and its environment. Animal information includes the rate of gain, which is the sum of lean gain and fat gain. Environmental information includes temperature and space per pig.
Pigs in thermal environments below their optimal temperature will use feed energy as fuel to generate the heat needed to maintain body temperature. Cold pigs will, therefore, require additional energy and their appetite will increase. However, the appetite is poorly matched to the increased need for energy due specifically to the cold stress. If the cold pig has free-choice access to feed, its appetite will result in increased metabolic energy available for all functions including fat deposition.
Crowding of growing swine has a negative impact on performance. Because performance is reduced, nutrient needs are reduced. The swine NRC and the companion application to this text show a reduced energy requirement in crowded swine. The space requirements are established as the minimum needed to avoid having a negative impact on performance. For pigs weighing less than 44 lb., the minimum space required is 4.4 [ft.sup.2] per pig. For pigs weighing 45 to 110 lb., the minimum space required is 11.4 [ft.sup.2] per pig, and for pigs over 110 lb., the minimum space required is 11.8 [ft.sup.2] per pig.
Protein in Swine Nutrition
In corn-based diets, protein is the nutrient most likely to be deficient. This is because corn is low in protein and what little protein there is in corn is of low quality. In addition, high-quality protein sources are expensive. A deficiency in protein results in reduced feed conversion, increased days to market, and a fatter carcass.
When it is said that the quality of protein in corn grain is poor, it means that the amino acid profile in corn protein matches up poorly with the animal's need for amino acids to make lean gain (Chapter 7). In selecting a protein source to mix with the corn grain, it is, therefore, important to find one where amino acid profile will make good the deficiencies of corn's amino acid profile. Soybean meal is one such protein source. Mixtures of corn meal and soybean meal have an amino acid profile that is relatively close to that required by swine to make lean gain. It is not a perfect match, however. Lysine is the amino acid that will be supporting the lowest amount of lean gain in corn-soy mixtures. Lysine is said to be the first limiting amino acid. Corn-soy diets can be made to support higher levels of lean gain by increasing the proportion of soybean meal or by adding a much smaller amount of lysine itself. Which solution is most economical will depend on the price of soybean meal and lysine.
In the swine NRC (1998) and in the companion application to this text, the lysine requirement is calculated from information describing the pig and its environment. Using the ideal protein concept (Chapter 7), swine nutritionists have established ratios that relate the requirement for each essential amino acid to the lysine requirement. Different ratios are applied to determine the essential amino acid requirements for maintenance, lean gain, and milk synthesis.
True Ileal Digestibility
Swine use amino acids to make body proteins. The primary source of these amino acids is feed protein. However, some of the amino acids in feed protein sources will not be absorbed as the feed passes through the pig's digestive tract. There are bioavailability differences among amino acids contained in the various feed protein sources. To address this issue, researchers work with ileal-cannulated swine, and based on the difference between the amino acids consumed and those that are collected at the ileum, they are able to assess amino acid bioavailability. Apparent ileal digestibility is calculated as the difference between what was consumed and what was collected at the terminal ileum. True ileal digestibility is apparent ileal digestibility corrected for the endogenous sources of amino acids that are collected at the ileum. The companion application to this text uses true ileal digestibility in predicting feedstuff amino acid value. It should be noted that the authors of the swine NRC prefer to use the term ileal digestibilities rather than bioavailability to describe this information because there will be some amino acids that are absorbed in a nonusable form. Table 14-2 presents three methods of expressing the amino acid content of feedstuffs: percent in feed dry matter, percent apparent ileal digestible in feed dry matter, and percent true ileal digestible in feed dry matter.
Relating Anticipated Carcass Traits to Nutrient Requirements
The two primary measurements that indicate desired qualities in a market hog are backfat thickness and loin eye area. The loin eye is the muscle in the loin region that gives rise to the pork chop product. The grade, quality, and yield of pork carcasses and wholesale cuts are related to these two indices. The desired loin eye area and fat depth at the 10th rib are carcass targets that can be used to calculate necessary carcass fat-free lean gain in the hog. The carcass fat-free lean gain can, in turn, be used to predict the amino acid levels that must be in the diet. These two indices are inputs in the companion application to this text. Most market hogs will have a loin eye area of 4 to 7 [in.sup.2] and a fat depth at the 10th rib of 0.4 to 1.6 in.
In general, performance is predicted by finding the difference between the total nutrient needed for maintenance functions and subtracting that from the total nutrient available in the diet. The difference is the amount of nutrient that can be applied to performance activity. The level of performance can be estimated by dividing the amount of nutrient that can be applied to performance by the nutrient cost for performance (Figure 14-3).
Feedstuffs Used in Swine Diets
The choice of which feedstuffs to use in formulating swine diets will depend on three factors:
1. What works to balance the ration
2. Feedstuff cost and availability
3. Feedstuff palatability
Low palatability may be an inherent characteristic of the ingredient, but palatability may also be influenced by moisture content and contaminants such as molds and toxins. Palatability may also be affected by the physical condition of the feedstuff, such as fineness of particle size or dustiness. Comments at the feed table in the swine ration formulation application accompanying this text give suggested feedstuff limits in swine rations.
Figure 14-3 Prediction of performance Nutrient amount that can be applied to performance: = (total nutrient available in the diet) - (total nutrient needed for maintenance functions) Level of performance: = (nutrient amount that can be applied to performance) / (nutrient cost for performance
Strictly nutrition-related questions regarding the suitability of feedstuffs for swine are best answered by work with the various feedstuffs in ration development. With accurate information on animal nutrient requirements and feedstuff nutrient value, the strengths and weaknesses of feedstuffs become apparent as nutrient balance is improved with successive feedstuff selections.
In large swine operations in the United States, swine diets are generally made by fortifying a corn meal and soybean meal mix with minerals and vitamins. Swine do not require corn meal and soybean meal, however. These two feedstuffs just happen to be relatively inexpensive and available in this country; they are palatable and they complement each other well in meeting swine nutrient requirements. On small operations and in other countries, balanced swine rations are formulated using a greater variety of feedstuffs. The companion application to this text calculates a level of performance that can be expected in a typical corn-soy diet for comparison with the ration developed with selected feedstuffs.
The optimal electrolyte balance for swine has been suggested to be 250 mEq/kg of excess cations, calculated using the sodium and potassium cations and the chloride anion (Austic & Calvert, 1981). The 250 mEq/kg is an as fed value, which, assuming a ration of 90 percent dry matter, would be 278 mEq/kg on a dry matter basis. Sodium, potassium, and chloride are the primary dietary ions that influence acid-base status in animals. The electrolyte balance may have application in the formulation of swine diets to maintain performance when animals are heat stressed (Haydon, West, & McCarter, 1990).
Phytase addition to swine diets has been shown to improve the utilization of dietary phosphorus (Cromwell, Stahly, Coffey, Monegue, & Randolph, 1993; Young, Leunissen, & Atkinson, 1993). This is important for two reasons. First, there may be an economic benefit: the use of phytase will enable swine to acquire the phosphorus from corn and soybean meal, and thereby eliminate the need to purchase supplemental sources of phosphorus. Second, there is an environmental benefit: the improved utilization of dietary phosphorus will reduce the excretion of phosphorus.
Feeding Antibiotics at Subtherapeutic Levels
Antibiotics are often fed at subtherapeutic levels to swine to improve feed efficiency and rate of gain. Because the use of antibiotics in livestock feed may lead to widespread microbial resistance and because such resistance may affect later therapeutic value of those antibiotics, management strategies to reduce resistance acquisition by bacteria may be warranted (Mathew, Upchurch, & Chattin, 1998). A discussion of issues related to use of antibiotics in livestock feed is found in Chapter 3.
The development of repartitioning agents for swine is an active area of research. Repartitioning agents redirect the use of nutrients with the result that the animal's metabolism is more focused on productive activities.
END-OF-CHAPTER QUESTIONS --
1. Why are day-old piglets routinely given a shot of iron dextran?
2. Describe segregated early weaning. What are the advantages and disadvantages of SEW?
3. For what nutrient is the anticipated loin eye area used to predict the requirement?
4. What classes of swine are usually given free choice access to feed?
5. What is the name given to the solid feed that is made available to the piglet while it is still with the sow?
6. On a farrow-to-finish operation, growing/ finishing pigs are usually fed at least three different rations: the nursery ration, the grower ration, and the finisher ration. Give the approximate weight ranges characteristic of pigs fed each of these rations.
7. The ideal protein concept in swine nutrition establishes the requirement for each essential amino acid based on the pig's predicted requirement for what?
8. In the United States, swine rations are usually made by fortifying two commodities with minerals and vitamins. What are these two commodities?
9. What is the difference between apparent ileal digestibility of an amino acid and true ileal digestibility of an amino acid?
10. At about what body weight do the nutritional requirements of barrows and gilts begin to differ?
11. Discuss the impact of crowding on nutrient requirements of penned swine.
Allee, G. L. (1983). The effect of particle size of cereal grains on nutritional value for swine. In First international symposium on particle size reduction in the feed industry (pp. D1-D9). Kansas State University (edited), Department of Grain Science and Industry.
Austic, R. E., & Calvert, C. C. (1981). Nutritional interrelationships of electrolytes and amino acids. Federation Proceedings. 40, 63-67.
Boland, J. P. (1966). In L. K. Bustad et al. (Editors), Swine in biomedical research. Seattle, WA: Frayn Printing Co.
Cromwell, G. L., Stahly, T. S., Coffey, R. D., Monegue, H. J., & Randolph, J. H. (1993). Efficacy of phytase in improving the bioavailability of phosphorus in soybean meal and corn-soybean meal diets for pigs. Journal of Animal Science. 71, 1831-1840.
Ensminger, M. E. (1993). Dairy cattle science (3rd edition) (p 408). Danville, IL: Interstate Publishers, Inc.
Giesemann, M. A., Lewis, A. J., Miller, P. S., & Akhter, M. P. (1998). Effects of the reproductive cycle and age on calcium and phosphorus metabolism and bone integrity of sows. Journal of Animal Science. 76, 796-807.
Haenlein, G. F., & Ace, D. L. (1984). Extension goat handbook (section E-1, p.3). Washington, DC: United States Department of Agriculture.
Haydon, K. D., West, J. W., & and McCarter, M. N. (1990). Effect of dietary electrolyte balance on performance and blood parameters of growing-finishing swine fed in high ambient temperatures. Journal of Animal Science. 68(issue 8), 2400-2406.
Lewis, L. D. (1982). Feeding and care of the horse. Philadelphia: Lea and Febiger.
Mathew, A. G., Upchurch, W. G., & and Chattin, S. E. (1998). Incidence of antibiotic resistance in fecal Escherichia coli isolates from commercial swine farms. Journal of Animal Science. 76, 429-434.
McNamara, J. P., & Pettigrew, J. E. (2002). Protein and fat utilization in lactating sows: I. Effects on milk production and body composition. Journal of Animal Science. 80, 2442-2451.
National Research Council. (1998). Nutrient requirements of swine (10th revised edition). Washington, DC: National Academy Press.
Veum, T. L. (1991). In E. R. Miller et al. (Editors), Swine nutrition. Boston, MA: Butterworth-Heinemann.
Yang, H., Pettigrew, J. E., Johnson, L. J., Shurson, G. C., Wheaton, J. E., White, M. E., Koketsu, Y., Sower, A. F., & Rathmacher, J. A. (2000). Effects of nutrient intake during lactation on weaning to estrus interval. Journal of Animal Science. 78, 1001-1009.
Young, L. G., Leunissen, M., & Atkinson, J. L. (1993). Addition of microbial phytase to diets of young pigs. Journal of Animal Science. 71, 2147-2150.
Table 14-1 Milk composition, as sampled basis Cow-- Cow-- Constituent Sow Holstein Jersey Goat Mare Fat (%) 7.2 3.7 5.1 3.8 1.5 Lactose (%) 4.8 4.9 4.9 4.1 6.0 Protein (%) 6.1 3.1 3.9 3.0 2.0 Holstein and Jersey data from Ensminger , 1993; Sow data from Boland, 1966; Goat data from Haenlein & Ace, 1984; Mare data from Lewis, 1982. Table 14-2 Methods of expressing amino acid value in feed used in swine nutrition. All values expressed as percentages. Dry Matter Apparent Ileal True Ileal Feedstuff Basis Digestibility Digestibility Lysine Corn 0.29 66 78 Wheat 0.43 73 81 Barley 0.22 68 79 Oats 0.45 70 76 Soybean meal 3.36 85 90 Tryptophan Corn 0.07 64 84 Wheat 0.30 81 90 Barley 0.12 70 80 Oats 0.16 72 78 Soybean meal 0.72 81 90 Threonine Corn 0.33 69 82 Wheat 0.44 72 84 Barley 0.39 66 81 Oats 0.49 59 71 Soybean meal 2.06 78 87 Methionine Corn 0.19 86 90 Wheat 0.25 85 90 Barley 0.22 80 86 Oats 0.25 79 84 Soybean meal 0.74 86 91 From NRC, 1998.
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|Author:||Tisch, David A.|
|Publication:||Animal Feeds, Feeding and Nutrition, and Ration Evaluation|
|Date:||Jan 1, 2006|
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