Wheat for Poultry and Swine Feeds

Dr. Kevin Herkelman
Wheat is mainly grown for use in human food production. The use of wheat in animal feeds is usually limited to times when wheat is competitively priced with corn or other grains. The high price of corn has increased the interest in the potential use of wheat in poultry and swine feeds. It is important to understand some of the characteristics of wheat to make proper feeding decisions when it is economically advantageous to use wheat.

There are two types of wheat typically available: hard red winter wheat and soft red winter wheat. Pennsylvania, Ohio, Illinois, and Indiana are leading producers of soft red winter wheat varieties, which are manufactured into cake, cracker and biscuit flours. In the Central and Great Plains states like Kansas, Oklahoma, Texas, and Nebraska, hard red winter wheat is grown for use in breads.
A nutrient comparison of hard red winter wheat, soft red winter wheat, and corn is shown in Table 1. Wheat contains less energy, but more protein and amino acids (methionine + cystine and lysine) than corn. Hard red winter wheat contains more phosphorus than corn, and both wheat types contain more available phosphorus than corn. Hard red winter wheat contains more protein and amino acids than soft red winter wheat, but contains less energy.

Although wheat contains more protein and lysine than corn, the balance of amino acids in wheat is rather poor. This means poultry and swine diets formulated with wheat should be balanced on an acid (methionine + cystine and/or lysine) basis, not a crude protein basis. Replacing corn with wheat on an equal protein basis decreases the dietary amino acid content of the feed and can result in poorer animal performance. Research from the University of Kentucky suggests wheat has a similar value to corn when diets are formulated on an equal amino acid and energy basis. The feeding value of the two types of wheat appears to be similar in poultry and swine when feeds are balanced on an amino acid basis.

Wheat available for use in animal feed is typically a “feed-grade wheat” and is often product rejected for human food production. Low test weight, sprouted grains, and the presence of mycotoxins are all factors which prevent the use of wheat in human foods. These same factors can reduce the nutritional value of wheat or even make it unsuitable for use in poultry and swine diets.

Wheat stressed by weather or disease often has lighter test weights. As the bushel weight of wheat decreases, the energy level of wheat also decreases. If a feed contains low test weight wheat (low test weight not taken into account), animals compensate by consuming more feed. Growth rate is often not influenced, but poorer feed efficiency can result.

Low test weight wheat can be used in poultry and swine diets, but the reduction in energy needs to be taken into account to prevent a reduction in performance. Fat supplementation can be used or light test weight wheat can be blended with normal test weight grain to account for the reduction in energy content. The price paid for light test weight wheat should take the reduced energy content into account.

High rainfall just before harvest can cause wheat to sprout on the head. Sprouted grain typically contains less energy than non-sprouted grain. The lower energy level makes the feeding recommendations for sprouted wheat similar to those for light test weight wheat.

Fungal diseases of wheat can reduce the feeding value of wheat. Scab can be caused by several fungi in the genus, Fusarium. Kernels infected with scab tend to be shriveled, chalky white, and some grains will be pinkish in color. Zearalenone and vomitoxin (DON) have been the mycotoxins associated with scabby wheat.

Zearalenone is commonly associated with reproductive problems in swine and the presence of vomitoxin in feed typically reduces feed consumption. The level of zearalenone and vomitoxin in the complete feed of swine should each be less than 1 ppm. The level of vomitoxin in poultry feeds should be less than 5 ppm. Since wheat available for animal feed use has typically been rejected for use in human foods, it is important to check for mycotoxin levels in wheat.

Wheat containing garlic bulblets can’t be used for human consumption. Wheat contaminated with garlic is subject to a rather severe price reduction. The performance of poultry and swine does not appear to be influenced by garlicky wheat containing up to 160 bulblets per pound. Wheat severely contaminated with garlic (> 600 bulblets per pound) is unpalatable to young pigs and can cause a garlicky flavor in pork. However, even severely contaminated wheat can be diluted with other grains to overcome the potential problems associated with garlicky wheat.

From a manufacturing standpoint, the use of wheat does improve pellet durability. The proteins in wheat help to bind ingredients during the pelleting process. Wheat can become very floury and can be somewhat unpalatable if ground too finely. Feeds containing finely ground wheat may flow poorly in feeders. For poultry, finely ground wheat can cause beak impaction due to the protein in wheat becoming sticky and adhering to the beak. In swine, finely ground wheat may increase the incidence of stomach ulcers.

Wheat should be coarsely ground and each kernel must be broken. A hammer mill with a ¼ inch opening in the screen and a reduced hammer speed can result in a desirable particle size. If all else fails, the amount of wheat added to the diet can also be limited in an effort to overcome some of the difficulties associated with handling diets containing finely ground wheat.

Wheat can be successfully used in poultry and swine feeds. Keep the following points in mind when considering the use of wheat.
1.     The decision to use wheat should be based on economics.
2.    Formulate diets containing wheat on lysine basis rather than a protein basis.
3.    The test weight of wheat should be determined and wheat should be examined for sprouted grains and the presence of garlic bulblets.
4.    Wheat should be tested for the zearalenone and vomitoxin.  The complete feed of swine should contain less than 1 ppm of each of these mycotoxins. Poultry diets should contain less than 5 ppm of vomitoxin.
5.    Coarsely grind wheat and make sure every kernel is broken.
6.    Replace only a portion of your grain if finely ground wheat is a potential problem.
7.    If you make a switch from corn to wheat, gradually increase the level of wheat in the diet to help animals adapt to wheat containing diets.

Phytase: A review of practical application

Dr. Kevin Herkelman

Phosphorus is a critical nutrient required by all animals. The main role of phosphorus is to support skeletal formation, mainly bones and teeth. Nearly 80% of the body’s phosphorus is contained in the bone. Phosphorus also plays a key role in carbohydrate metabolism, fat metabolism, lean tissue deposition, and as a component of phospholipids, which are important for proper cell structure.

Table 1 shows the phosphorus content of typical ingredients used in poultry and swine feeds. Plant-based ingredients like corn, wheat, soybean meal, wheat middlings, and Distiller’s Dried Grains with Solubles (DDGS) are fairly low in phosphorus

Table 1. Phosphorus Composition of Ingredients Used in Poultry and Swine Feeds

content. A typical combination of corn and soybean meal (the most common ingredients used in poultry and swine feeds) will provide less than half of animal’s requirement of phosphorus.

Animal byproducts such as meat and bone meal and poultry byproduct meal contain much higher levels of phosphorus than the plant based ingredients and can be important sources of phosphorus in animal feeds. Dicalcium phosphate, an inorganic phosphorus source, contains a high level of phosphorus compared to plant and animal based ingredients. However, due to cost, inorganic phosphorus sources are typically only included in the diet at levels to fill the gap between the animal’s phosphorus requirement and the level of phosphorus provided by other dietary ingredients.

Unfortunately, not all of the phosphorus in feed ingredients is available to animals for productive purposes. In grains and seeds, this is due to phytate. Phytate is a complex molecule that binds phosphorus (and other nutrients) for storage in seeds and grains. Between 60 to 70% of phosphorus in plant based ingredients occurs as phytate bound phosphorus. This phytate bound phosphorus is unavailable to the animal, because the digestive tract lacks adequate amounts of the enzyme (phytase) necessary to release the phosphorus from the phytate complex.

Table 2. Comparison of a Swine Diet With or Without Phytase

Phytase is an enzyme capable of releasing phosphorus from the phytate complex in grains and seeds. This phytase is a specific, commercially-available phytase product added to the diet to release phosphorus. Any phosphorus released by phytase from ingredients is then available for use by the animal to meet phosphorus requirements and to be used for productive purposes.

Phytase activity is typically expressed as “phytase units” or “FTU” per unit of feed. In general, 500 FTU of phytase per kilogram of feed liberates 0.10% phosphorus from dietary ingredients. In addition, this level of phytase also liberates calcium and other nutrients bound to the phytate molecule.

Table 2 shows a comparison of a swine grow-finish diet formulated with and without phytase. The addition of phytase decreases the amount of supplemental phosphorus (dicalcium phosphate) required to be added to the diet. In addition, the amount of supplemental protein (soybean meal) is also reduced.

The total amount of phosphorus in the diet is decreased 0.10% (0.50 to 0.40%). However, the amount of available phosphorus (the amount of phosphorus available to the animal for productive purposes) is the equal between the diets. This is because we are making more of the phosphorus from dietary ingredients “available” when phytase is added to the diet. In addition, feed cost is substantially decreased due to the competitiveness between suppliers of commercially-available phytase and the high cost of inorganic phosphorus supplements.

One major advantage of using dietary phytase is reduced phosphorus excretion. The phytase containing diet in Table 2 indicates total phosphorus in the diet can be reduced 0.10% with less inorganic phosphorus supplementation. This reduction in total phosphorus in the diet results in a similar reduction in the amount of phosphorus excreted by the pig (phosphorus not used by the pig).

Table 3. Effect of Phytase on Phosphorus Excretion

Table 3 demonstrates the effect of using phytase on phosphorus excretion. Experimentally, daily phosphorus intake was equalized between pigs fed diets with and without phytase (not done practically), the digestibility of phosphorus was increased nearly 11% when phytase was added to the diet. The addition of dietary phytase decreases the amount of phosphorus excreted through the feces by approximately 17%.

The decrease in phosphorus excretion determined experimentally has also been evaluated on a practical basis. Table 4 illustrates the effect of reduced phosphorus diets on total manure phosphorus excretion and the amount of land required to manage the level of phosphorus. The ability to reduce phosphorus level through the use of phytase resulted in a 31% reduction in phosphorus excreted. This resulted in a reduction in the amount of land required to handle the phosphorus excretion in the two types of manure storage systems analyzed.

Table 4. Manure Phosphorus Excretion and Land Required to Manage Excretion in a 1,000 Head Capacity Pig Finishing Building

In summary, phosphorus is a critical nutrient required by poultry and swine. Unfortunately, a significant portion of the phosphorus in typical ingredients is unavailable for productive use by animals due to the phytate complex. The use of dietary phytase releases previously unavailable phosphorus, reduces the amount of supplemental phosphorus, and reduces feed costs. In addition, phosphorus excretion and the amount of land required to handle excreted phosphorus is reduced when phytase is added to poultry and swine feeds.

Split Sex Feeding

Dr. Kevin Herkelman
Gilts typically grow slower, are more efficient in the utilization of feed, and are leaner than barrows. We would predict that gilts require greater concentrations of amino acids than barrows. Split sex feeding (feeding gilts and barrows, separately) offers the potential to take advantage of these differences between barrows and gilts. In addition, the improved targeting of amino acid needs of barrows and gilts separately could help tighten weights when pigs are marketed.

An experiment was conducted to evaluate the response of gilts and barrows to two levels of lysine. The experiment was conducted at the Jim Charles Swine Finisher Research Barn. Nine hundred ninety-six pigs, initially weighing 64 pounds, were allotted to four treatments and fed to a market weight of 281 lb. Gilts and barrows were fed separately and fed either standard diets or the standard diets with a 0.1% increase in lysine (1st limiting amino acid in swine diets).

Overall, barrows grew faster than gilts (2.21 vs. 2.10 lb/day) but were less efficient in the utilization of feed (2.37 vs. 2.25 feed:gain) than gilts. The increase in growth rate of barrows was consistent throughout the experiment. During the grower stage (64 to 91 lb body weight), barrows and gilts had similar feed conversion rates. However, barrows were less efficient in the utilization of feed during the rest of the experiment, and the difference between barrows and gilts increased as pigs approached market weight. At slaughter, barrows produced heavier carcasses, had more backfat, and produced a lower percentage of primal cuts than gilts.
An increase in dietary lysine improved the growth rate of pigs from 64 to 129 lb body weight and feed conversion from 64 to 91 lb body weight. This response was similar for barrows and gilts. Overall, there was no benefit to the increase in dietary lysine for barrows or gilts.

These results indicate that the standard lysine level used in this experiment was sufficient to support maximum growth rate in barrows and gilts. However, both barrows and gilts did benefit from increased lysine in the grower stage. Because barrows grew faster than gilts, we would estimate that the lysine levels of barrows could have been reduced and still maintained performance; although additional research would be needed to confirm.

High Feed Costs? Think Feed Conversion

By Dr. Kevin Herkelman, Product Support and Development Manager
Corn is the main ingredient used in swine diets and contributes the major feed ingredient cost in animal production. The increase in current and proposed ethanol production has helped to increase the price of corn. The higher corn prices appear to be more than a short term event. Prices of other ingredients are also changing relative to the price of corn resulting in substantial increases in feed prices.

It is important to continuously monitor alternative ingredients and consider their possible use in diets. However, corn will likely be the major ingredient in swine diets. If we look at higher feed costs as a whole, anything to improve feed efficiency can help maintain or improve profitability.

Feed conversion during the grower and finisher period is a key factor to monitor. This is the period of the animal’s life when a majority of feed is consumed. The efficiency of feed utilization can be dramatically influenced by factors such as feed wastage, nutrient levels in diets, feed budgets, diet form (pellet or mash), the use of additional fat, and other environmental factors.

The influence of average feed cost and feed:gain ratios on feed cost per pig are shown in Table 1. Feed efficiency is always important to monitor, but an increase in average diet cost makes feed efficiency even more important. An example will be used to demonstrate the importance of feed efficiency relative to price of feed.

Table 1. Feed Cost/Pig (50 to 260 lb) at Various Feed Prices and Feed:Gain Ratios.

Assume an average feed cost of $300/ton and a feed:gain ratio of 2.70. The feed cost per pig is $85.05 per pig (see Table 1). If average feed cost increases to $325 per ton, feed cost per pig increases to $92.14 per pig (an increase of $7.09 per pig!). At $325/ton, a reduction in feed:gain ratio from 2.70 to 2.60 decreases feed cost $3.41 per pig ($92.14 to $88.73 per pig) accounting for nearly half of the increase in diet cost from $300 to $325. Feed cost per pig decreases to a greater degree as feed prices increase. Anything producers can do to improve feed efficiency during periods of high feed prices will help reduce feed costs.

Management-wise, how do you improve feed conversion? Feed wastage is probably the most critical factor that can be controlled on-farm. Routine and proper feeder adjustment throughout the life cycle is essential. For grow-finish pigs, only 40 to 50% of the pan should be covered with no feed in the corners. Also, make sure feeders are in good working condition and are appropriate for the animals being fed.

Diet form is also important to evaluate. In general, less feed is wasted when feed is fed as pellets. Pellets can improve the feed conversion 5-8% throughout the grow-out period. As mentioned previously, some of this improvement is due to a decrease in feed wastage.

At an average diet cost of $300 per ton, diets manufactured as pellets can reduce cost $6.30 per pig (feed conversion reduced from 3.00 to 2.80). Typically, it costs ~$6.50 per ton to pellet a diet, which equals $1.91 per pig (588 lb feed x $6.50/2000 lb feed) to pellet feed. The net effect of pellets in this situation is a $4.39 per pig savings ($6.30 per pig savings in feed – $1.91 per pig cost to pellet). The return from pellets increases as diet cost increases.

Dietary nutrient levels (especially lysine and energy) also influence the efficiency of feed utilization. It is important to be sure you are feeding the right diet during each phase of production. If nutrient levels are too high, you are unnecessarily increasing diet cost and getting no return. In contrast, if nutrient levels are too low, performance will be reduced and productivity (daily gain and feed conversion) will be compromised.

It is difficult to establish general nutrient requirements (i.e. energy, amino acids, etc.). A variety of factors (environment, overcrowding, etc.) can influence nutrient requirements in a given situation. It is important to work with a nutritionist and evaluate close-out information and current feeding programs to establish areas where diet changes can improve profitability.

Feed budgets are another part of the equation to monitor. The correct diets may be fed, but if we are using feed budgets (feeding a certain amount of a feed per animal), we need to be sure we are feeding the appropriate budget for the appropriate stage of production. Again, over-feeding a certain phase can unnecessarily increase diet costs, while underfeeding a certain phase can reduce performance.

For producers mixing feed on farm, the economics of utilizing fat or other high energy ingredients should be evaluated. As a rule of thumb, feed conversion is improved 2% per every 1% increase in dietary fat. Certainly, adding fat to the diet is going to increase diet cost. In addition, lysine levels should be increased when adding fat to maintain an equal lysine:calorie ratio. Information from Table 1 can be used to determine if the addition of fat is an economical choice.

Let’s assume a producer has average closeouts with a 3.00 feed:gain ratio from 50 to 260 lb body weight with an average diet cost of $300 per ton. At this level of production, feed cost per pig is $94.50. He determines that he could add 5% fat to his diets, which will increase average diet cost to $325 per ton. Is it economical to add fat to diets?

We would estimate feed conversion will be improved from 3.00 to ~2.70 (5.0 x .06= .30 unit improvement). At a diet cost of $325 per ton, feed cost per pig would be $92.14. In this case, fat is a good buy with a decrease in feed cost of $2.36 per pig. Keep in mind, the producer must have the ability to handle and store fat on-farm. If a producer doesn’t currently have the ability to handle fat on-farm, the potential payback from making an investment in fat storage can be estimated.

There are many other factors influencing feed conversion that are important to evaluate. Genetics, health status, ventilation, etc. are all factors that can influence feed conversion. These factors plus those discussed in this article are all important to evaluate at anytime, but at higher corn (diet) costs, evaluating these factors is even more critical to maintain or improve profitability.