Over the last couple of issues we've been taking an in depth look at a number of the by-product feeds that are available to the cattleman as part of his feeding and supplementation program. A key factor to remember is that there are no perfect feeds or ingredients but that several should be used together to develop the best possible nutritional program.
This being said, it must be noted that research and experience has shown that some ingredients can be used in greater proportions of the animal's total diet than others. Table 1 illustrates this fact by providing suggested inclusion levels of quite a number of ingredients in the animals daily feeding program.
|Table 1. Suggested Limits for Feeds in Beef Rations.
Table adapted from Gill, et al., UT Beef and Forage Field Day Proceedings, 1999.
As noted these are suggested levels and should be used as a rule of thumb when developing a feeding and supplementation program.
On to Bigger and Better Things
As in the past issues, let's take a look at a couple of more by-product feeds that have become valuable members of the feed industry's list of useful ingredients.
Hominy feed is a by-product from the manufacture of pearl hominy, hominy grits or table meal from corn. It is similar in appearance to ground corn, has slightly more energy and protein, and has similar feeding characteristics. It contains the corn bran, germ, and some of the starchy portion of the corn kernel resulting from the production of de-germed corn meal for human consumption. It is about equal to ground corn in feeding value and is very palatable to livestock. Levels of 50 percent or more of the concentrate mix have been used successfully in cattle rations. In complete feedlot rations, as high as 70 percent has been fed successfully but a 10 to 15 percent level is more common. Normally, hominy feed contains 6 percent or more of fat. When part of the fat is removed, the resulting low fat hominy feed is somewhat lower in energy value. However, both forms are good energy sources and have higher protein levels than in the corn grains from which they were produced. Table 2 below illustrates more of the nutrient values commonly found in hominy.
Hominy should be analyzed for its fat content, which can vary considerably due to the type of manufacturing process. As fat content drops, so does the level of Total Digestible Nutrients (TDN). For example, hominy containing 1.5 percent fat will have 82 percent TDN.
Suggested feeding rates for hominy are similar to corn grain. However, as noted above, an adjustment may need to be made in the quantity of hominy feed fed due to variations in fat content. Fat content of hominy feed may range between 5 to 12 percent. If the ration has other fat containing feeds such as whole soybeans or whole cottonseed, then it may be necessary to limit the quantity of hominy fed to avoid high levels of added fat in the total ration. All in all, hominy is a palatable feedstuff and is normally safe to feed in large quantities and can be included in the grain mixture at high levels.
One of the primary products available to the feed industry from the distilling industry is dried distillers grains (DDG) or dried distillers grains plus solubles (DDGS). These grains are commonly produced using corn, milo, rye, or barley as the base feed for the fermentation process. The primary grain is used to name the resulting product. As an example, corn distillers grains would be produced from a fermentation in which corn was the primary grain used. Some variation does exist in the distillers grains produced from the different base components and the exact nutrient content should be considered when purchasing a given product. Table 3 provides some basic nutrient data for Corn Distillers Grains.
A primary factor to consider when evaluating any feedstuff for inclusion in a ration is the variability which may exist in nutrient composition. There are a large number of factors which can influence the nutrient composition of distillers grains. The primary factors which influence composition are type of grain used (as noted above), mash bill, grain quality, grinding procedure, fermentation conditions, drying conditions and the quantity of solubles blended into the fibrous portion of the grains. For example, in a study by Shelford and Tait (1986) it was noted that rye distillers grains were lower in protein and higher in ADF than corn distillers grains. This simply goes to say that feed industry personnel should keep a log of ingredient nutrient composition by supplier to better define the feedstuffs purchased. Producers should request exact nutrient information pertaining to the exact product being purchased at the time of delivery.
One aspect of distillers grains which is of interest to cattle nutritionists is undergraded intake (bypass) protein content. Studies have shown repeatedly that a tentative estimate that the By-pass portion of distillers grains was around 55 percent of the total protein. An important question in utilizing distillers grains as a bypass protein source is the variations which may exist in the protein fractions.
Once again we find more feed ingredients that can be effectively used in the design of a sound nutritional program. An important fact has been brought to light, however. In most by-product type feed ingredients, we see significant variability in the nutrient content as related to the type of base grain used, process used and a host of other variables. It is very important that the producer knows exactly what he is buying and if not that he has the product analyzed to insure appropriate utilization.
Dr. Steve Blezinger is a nutritional and management consultant with an office in Sulphur Springs, TX. He can be contacted at Route 4 Box 89 Sulphur Springs, TX 75482, by phone at (903) 885-7992 or by e-mail at firstname.lastname@example.org.