Without question, meeting the energy requirements of your cattle is the most expensive component of your feeding program. Typically we rely on cereal grains such as barley, feed wheat or corn to meet the energy needs of cattle for maintenance and gain and in some cases pregnancy. While it is too early to know the nature of this year s barley crop in Western Canada, it is evident the corn supply in the U.S. will be tight and as a result we are likely to see upward pressure on cereal grain prices. To counter this increased cost, many cattle feeders and cow-calf operators look to byproduct feeds as energy substitutes for cereal grains. The type and nature of these byproducts is extremely variable. Most are produced as a result of value-added processing of the grain, oilseed and vegetable sectors. Examples include cull potatoes and beans, byproducts from grain and pulse processing (i. e. oat and pea hulls, grain screenings, wheat midds), distillers grains and milk processing byproducts, to name a few. Each has unique nutritional characteristics and in order to make effective use of a given byproduct, we need to understand nutritionally what they are contributing to the ration and how they influence performance and cost of gain.
To give an example, consider grain screenings a byproduct of the grain cleaning industry. Screenings are comprised of unwanted material such as chaff, small weed seeds, foreign and/or broken grain kernels that are removed when grain is cleaned. Grain screenings are a good source of protein for cattle, typically averaging 13 to 15 per cent (dry matter basis). However in terms of energy, grain screenings are at best an intermediate source, typically the value of a light oat. Processed (ground and pelleted) grain screenings can be used to replace barley grain in wintering rations for cows as well as in backgrounding programs.
The biggest issue will be to remember that if you are replacing barley grain with grain screenings, you need to increase the amount fed by 10 to 15 per cent to maintain the same energy content in the diet (15 to 20 per cent in the case of corn). This increased intake should be considered when pricing processed grain screenings relative to cereal grains. The biggest concern with grain screenings is variability in nutrient content between loads from the same or different sources. To get around this issue, the feed industry has developed fortified grain screenings. While each company may have a unique formula, fortified grain screenings are screening-based products that have been blended with barley or feed wheat to target a specific energy level in the pellet. In some cases, oilseeds can be added to the mix to provide a high-fat pellet that again is more consistent in energy content.
Fortified grain screenings can be custom formulated to meet all mineral, salt and vitamin requirements and can include feed additives such as an ionophore. These products are a convenient means of supplementing cattle to meet their nutritional needs for growth or pregnancy. However for finishing cattle, their use can be limited due to energy density.
Lentil and pea screenings can also be a smart buy, particularly if you are located near a source. Relative to grain screenings, they are a superior source of both energy and protein.
Another example is the use of canola meal as a protein supplement. Canola meal is a byproduct of the oilseed crushing industry and its supply is increasing due to industry expansion. Canola meal is a great source of crude protein for cattle, averaging 38 per cent or better on a dry matter basis. Its combination of rumen degradable and undegradable (bypass) protein is well suited for growing and finishing cattle. However, as with screening byproducts, canola meal is an intermediate energy source. This fact and relative cost dictates that inclusion rates reflect its value as a protein supplement and not as an energy supplement.
As a final example to illustrate the versatility of byproducts, consider the use of whey permeate from the milk-processing sector. This product is approximately 22 per cent dry matter and 3.5 per cent crude protein (dry matter basis). However, on a dry matter basis, it is 80 per cent lactose, which when fed in moderation, serves as an energy source in the rumen of cattle. Producer experience feeding this product at 15 to 20 per cent of the ration (as fed) is that it increases your flexibility as a feeder. For example, in feeding programs that rely on processed hay as the forage source, the use of whey permeate is a means of adding moisture, controlling dust and enhancing intakes. This can reduce cost of gain, particularly when hay is cheap.
One of the recent trends in byproduct feeding is the replacement of cereal grains in backgrounding and finishing diets with high protein byproducts such as distillers grains. Next month we will examine this practice.
JohnMcKinnon isabeefcattle nutritionistat theUniversityof Saskatchewan