In this column, I have talked a lot about alternative feeds. While I believe byproduct feeds have their place, chances are if you are backgrounding or finishing cattle, your feeding program is centred on barley or corn. Some of you may however be tempted to feed wheat this winter, so to avoid any surprises, let s look at some of the issues you will face.
If you are buying feed wheat, two important considerations will be price and supply. The implications of pricing are obvious and I will come back to value shortly. Supply is equally important for several reasons. First, incorporating wheat into the feeding program means significant changes in feeding and mill management. Before undertaking these changes, you want to ensure that you will have an adequate supply. The last thing you want to do is to move cattle onto and then off wheat-based rations. As we will see, it is simply too hard on the cattle.
How does wheat influence your feeding management? The answer to this question is found in the rumen. Fermentation of starch in cereal grains by rumen bacteria results in the production of short chain fatty acids. These acids are released into the rumen and stress the animal s ability to maintain rumen health and proper digestive function. The faster the rate of starch fermentation, the more acid produced and the greater the stress on rumen health.
It is in this context that wheat is often referred to as a hotter cereal grain than barley or corn. All three cereal grains are excellent sources of starch, with wheat and corn superior to barley. With respect to the rumen, however, the greatest difference between these three grains will be in the rate of starch breakdown. Of the three, wheat has the fastest rate of starch fermentation, followed by barley and corn. The high starch content of wheat and its rapid breakdown in the rumen will result in more acid production and greater stress on rumen health. This stress can lead to an increase in the incidence of digestive disturbances, particularly sub-acute acidosis. Performance suffers due to erratic feed intake, reduced gains, poor conversions, lameness and issues with liver abscesses. In a worst-case scenario, cattle can die from grain overload. To minimize these issues, most nutritionists recommend blending wheat into the ration and placing an upper limit on the amount fed. I place a maximum inclusion rate at 50 per cent of the grain portion of the ration. In a finishing diet, this means a maximum of 40 per cent wheat in the total mixed ration (DM basis).
While the amount fed is important, you also need to consider how you get to this level. The answer carefully! My recommendation is to replace 10 per cent of the barley (or corn) in the diet, with an equal amount of wheat. Give the cattle two to three days to adapt to this change, if the cattle are eating normally, increase again in a similar fashion. Follow this program until you reach the desired inclusion level.
While the focus of this article is on wheat, do not let me leave you with the impression that barley and corn feeding programs are free from issues with digestive disturbances. Bunk management is just as important when feeding these grains. The point is that the hotter nature of wheat means that you need to be at the top of your game when it comes to bunk management. Mistakes such as over-feeding, moving cattle up on rations too quickly, excessive fines in the bunk are that much more serious with wheat-based rations.
Mill management also needs to change when feeding wheat. First you need additional bin space. It is also recommended to process wheat separately from either barley or corn. This is to ensure proper processing of each grain and to minimize any issues with whole kernels or excessive fines. Wheat can either be dry rolled or tempered prior to rolling, taking care not to over-process. Grinding is not recommended as it can lead to excessive fines which compound the negative effects on rumen function and performance.
Other concerns with feed wheat, particularly with grain purchased locally, include frozen or sprouted grain. As we have discussed in past issues (i. e. November, 2010) unless you are dealing with severe damage (i. e. very light test weight grain), feeding value is not greatly affected. Also be on the watch for excessive mould contamination, particularly ergot and fusarium head blight.
Feed wheat is an excellent energy source for cattle, generally superior to barley and approaching that of corn grain. When competitively priced, feed wheat is a good buy and with proper management should result in better feed conversions, particularly as a replacement for barley. However, because of the supply and feeding management issues discussed, most feedlots in Western Canada do not look at bringing wheat into the ration until the price approaches or is at a discount to barley. For corn feeders, particularly in Eastern Canada, added transportation costs for western feed wheat and supply issues will need to be factored into the decision.
JohnMcKinnon isabeefcattle nutritionistat theUniversityof Saskatchewan