Steve Bolden, Director of World Technical Support Team, Cobb-Vantress Yellow corn and wheat continue to be the two dominating cereal grains used worldwide in the broiler industry. Corn is the leading grain in North and South America, the Mideast, Africa and Asia, while wheat prevails in Western Europe, Australia, New Zealand and certain provinces in Canada. Although these two cereals are different, each with unique characteristics and challenges, our knowledge has grown concerning how to formulate, and at times, interchange these grains to achieve essentially equal performance in broilers. To remain cost-competitive in today’s dynamic, economic environment, nutritionists must be willing, and prepared, to switch to the alternate cereal grain source at various levels of inclusion. Very often, broiler nutritionists are hesitant to use an alternate grain, even when the economics are favorable, simply because of negative past experiences. A great example is the North America broiler industry views wheat, as a result of the summer of 1996. Due to poor harvest, corn availability was extremely low and the broiler industry was forced to move to wheat-based diets for many weeks or months. Complicating this transition was that most feed mills did not have the ability to grind and store both wheat and corn, so broilers faced an instant transfer on to wheat without the benefit of a graded acclimation over time. Overall, feed performance in North America declined as integrators moved to the wheat diets. However, the reasons were explainable. First, there was also a shortage of good quality feed fat, forcing the industry to move to diets that were 60-90 kcal / kg lower than the corn diets because of the lower caloric value of wheat. Secondly, cereal enzymes were just emerging and the industry did not have today’s knowledge of how to use them appropriately. Some integrators attempted to use an enzyme, while other nutritionists elected to use the wheat “as is.” Thirdly, nutritionists did not have the volume of information available to them that we have today, especially concerning amino acid digestibility differences between corn and wheat. Wheat kept the N. America broiler business afloat in 1996. However, wheat was forever categorized by many production managers as harmful to performance. Regardless of our negative past experiences, integrators must now take advantage of the information available and be prepared to change to the ‘other grain’ as cost savings opportunities arise. Key fundamentals of buying grain Globally, corn is typically less complicated to specify for purchasing and should be more predictable. However, corn can still be extremely performance-diminishing to broilers if certain key purchasing guidelines are not followed. With corn, there are six main quality check points that will go a long way in assuring that you have no major cereal issues: Your corn: Should, first and foremost, be cool on arrival, with no odors Should arrive with less than 15.5 percent moisture Should have a minimum test weight of 65kg/hl (52 lbs./bu) Should have a maximum of 7 percent damage (heat, etc.) Should have a maximum of 4 percent broken kernels + foreign matter (by weight) Should have a maximum of 20 ppb aflatoxin If these six simple guidelines are followed, other issues with corn will be very minor. Be cautious especially about the moisture level as grain terminals and vendors have become very skillful in blending corn to your maximum allowable level. To those who do not use wheat on a regular basis, wheat will appear to be more complicated to specify than corn due to the multiple hybrid varieties of the cereal. Depending on the region of the world, wheat can be sold as hard or soft, as red or white, or often classified as winter or spring wheat. Wheat that is classified as ‘hard’ will have higher protein but will carry a slightly lower starch content, and thereby lower caloric value, than varieties considered ‘soft.’ The nutritionist considering using wheat, needs to be familiar with its analytical content and make every effort to achieve consistency of supply and supplier. Otherwise, the nutritional matrix of the wheat will be subject to ongoing change, requiring constant shifting of the formulations to avoid loss of broiler performance or cost efficiencies. Besides understanding the nutritional content, these six checkpoints should be used: Your wheat: Like corn, should be odor-free and cool on arrival Should arrive with less than 13 percent moisture Should have a minimum test weight of 72.5 kg/hl (55 lbs/bu) Should have a maximum of 7 percent heat-damaged kernels, and 1.3 percent maximum foreign material Should have a maximum of 8 percent shrunken and broken kernels Should have maximum established limits on mycotoxins, such as DON (Vomitoxin, ≤10 ppm) In many regions of the world, it will be difficult to adhere to all of these key rules. The nutritionist needs to be very familiar with any deviations so formulation values can be adjusted. Key formulation considerations What other steps that must be taken to assure a good, seamless move between cereal grains? Even with high quality corn and wheat cereals, the nutritional contents, by nature, will be different: When considering changing cereal grains, the economic value of the change should first be made on an isocaloric basis, using the same protein and amino acid minimums. As stated earlier, isocaloric/ isonitrogenous diets can result in identical performance on corn or wheat. In general, using a full wheat broiler diet will require the addition of 2 percent or more liquid fat equivalent. Determination needs to be made as to the availability and cost of the fat. If fat is not available, then lower energy diets must be used, which may bring other questions into consideration: Will it matter that our broilers have a slower daily gain? Will it be an emotional issue for feed conversions to go higher? Can our feed mill produce and deliver more feed to compensate for the higher feed conversions? Once these questions have been answered, some good performances and cost savings can still be captured regardless of the calorie level of the feeds. Need to adjust nutrition and management Both corn and wheat contain certain poorly-digested complex carbohydrates, known better as non-starch polysaccharides, or NSP’s. It has been shown that supplemental enzymes can help break down these compounds thereby creating an added energy release or lift from the feed. Wheat contains a greater array of NSP’s than corn, including arabinoxylans and beta-glucans, which can increase gut content viscosity and diminish the availability of nutrients. Enzyme supplementation to wheat will typically need to be slightly higher and more specialized than corn. Fortunately, there are multiple liquid and dry enzymes available from several companies that pinpoint the exact substrates found in wheat. Many of these products are very similar, enabling the purchaser to benefit from the competition of pricing. While the amino acid levels are higher for wheat than corn, the digestibility coefficients are slightly lower and should be accounted for using digestible amino acid formulation, and ‘ideal’ ratios. The Ajinomoto Heartland website (www.lysine.com) is an excellent resource for these ingredient values. If the higher protein hard wheat varieties are used, phosphorus levels are typically higher than those of soft wheat or corn. With today’s phosphorus prices, this seemingly small factor can be a great contributor in cost saving. The exact phosphorus levels should be confirmed via lab analyses. With the rapidly emerging value of chicken feet, other slight modifications might also be necessary when using wheat. Wheat contains less biotin than corn, so increasing the level of synthetic biotin is advisable, especially given the role of biotin in reducing pododermatitis. Also, despite the improvements of wheat afforded by the enzymes, the excrement from wheat-fed broilers still tends to be slightly more viscous and sticky, which can lead to more foot burns. When using wheat diets, it is important to raise the focus on litter quality, ventilation, water consumption monitoring and possibly feed sodium levels. Feeding wheat has been shown to predispose broilers to higher incidences of necrotic enteritis, presumably due to the higher levels of NSP and higher gut viscosity. However, recent enzyme studies have shown this concern to be reduced with the emergence of the specialty NSP enzymes. Partial inclusion of whole wheat or coarse-ground corn With many feed mills not able to grind and store both corn and wheat, broiler producers and nutritionists have recognized the benefit of using whole wheat grains rather than grinding it, up to levels as high as 15 percent. The benefit is two-fold: 1) the cost advantage of being able to participate in a favorable, seasonal wheat market, and 2) a feed conversion benefit from including the granular whole grain. Nutritionists have tried a similar approach with corn grind size. Ideally, corn-based diets are ground to the point of achieving maximum starch exposure to the steam-pelleting process, resulting in an excellent pellet and crumble. However, in reality, many feed mills have the capability to grind corn appropriately, but are under-equipped on the pellet lines. In these cases, companies have compromised die thickness, pellet hole diameters and sheer throughput, resulting in pellets that become pulverized well before being presented to the bird. The result is a prevalence of fines in the pans which slows down consumption, growth and performance. Since today’s broiler does not thrive on powder, many companies have moved to coarser corn grinds and have seen improved bird performance. Pellet quality is certainly not improved, but the resulting mix in the pan at bird-level is more uniform and consumable, thus better for gizzard development and feed conversion. This approach should be taken cautiously, perhaps starting at grower and finisher ages.