In this issue we will continue the 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. We've found that these feeds take a number of different forms and are useful in supplementing different key nutrients, especially protein and energy. The by-products we'll examine here take two different forms – wet and dry.
While there are several by-products that can be produced in association with the production of beer, such as, brewer's grains (wet or dried), brewer's dried yeast, etc., brewer's grains are probably the most extensively used. These materials are considered to be good sources of un-degradable protein and water-soluble vitamins. They have been used in feeding both ruminant and monogastric animals (monogastrics using predominantly the dried forms).
Brewer's grain is the material that is remaining after grains have been fermented during the beer making process. These materials can be fed as wet brewer's grains or dried brewer's grains. The nutritional content of the material will vary from plant to plant and depending upon the type of grain used (barley, wheat, corn, etc.) in the initial brewing process as well as proportions being fermented and fermentative process being used. Some breweries will dry the brewer's grain and sell it as dried brewer's grain, while others will have it available as wet brewer's grain. Both types have similar feeding characteristics if the wet brewer's grain is fed shortly after it is produced.
Wet brewer's grains is basically a sterile material when it leaves the brewery. The material is produced from products that are food grade quality and are subject to extensive heating for extended periods of time during the mashing process. The heating of the grains serves to help in two areas, one being increased palatability and the other being the establishment of high levels of bypass proteins. Brewer's grains, in fact, are rated as having one of the highest values of bypass protein in commonly available feed stock. Although the rumen degradability of the protein in the dried brewer's grain is lower (higher rumen by-pass), which is directly related to the amount of heat that it is subjected to during the drying process.
Wet brewer's grains need to be used in close proximity to the plant producing them, since they contain large amounts of water (75-80 percent) and transporting can be expensive. On the other hand the water that it contains maybe very advantageous to livestock producers in areas where water quality and supply are limited. This also tends to increase the palatability of the product.
Brewer's' dried grains are very palatable to cattle, provide bulk to the concentrate mix, and serve as a good by-pass protein (degraded relatively slowly in the rumen). In dairy rations they may be included in the concentrate at a rate of 20 to 25 percent or in complete feeds to provide an intake of 8 to 10 pounds daily per cow (as fed). Higher amounts may reduce the overall desired energy concentration of the ration. Table 1 below provides some basic nutrient information.
Table 1. Typical Analysis
Storage and Handling Considerations for Wet Brewer's Grains
The wet brewer's grain are normally fed fresh, but can be ensiled. If ensiled, the quality of the wet brewer's grain (WBG) silage can be improved by adding a readily fermentable carbohydrate source such as molasses, ground cereal grains, etc. This will accelerate the fermentation rate, which results in more acids being produced and a more stable silage. Packing and ensiling characteristics can be improved by blending the wet brewer's grains prior to ensiling with other material that are dryer (forage, bran, hulls, etc.). If wet brewer's grains are ensiled alone then excessive runoff may occur, so it is best to ensile it in a silo with proper drainage.
If fed as wet brewer's grains care needs to be taken to assure that it does not deteriorate prior to being fed. Since wet brewer's grain provide very good conditions for microbial growth (i.e. yeasts and molds), it is best to feed the material as soon as possible after receiving it. It is best not to store the material much longer than a week to 10 days prior to feeding it, especially in hot or warm areas. Research has found that wet brewer's grain could be stored fairly effectively for 10 days in spring, 5 days in summer and 30 days in winter. If storing for longer periods of time the material should be ensiled. Under hot and humid conditions it might not be possible to store the material for a week. Storing in a shaded or cool place will length the time that the wet brewer's grains can be stored. Covering the surface with plastic or some other covering material will minimize surface spoilage and length the time that the material can be stored. Feed consumption will be reduced if spoiled brewer's grain is fed. Also, feed mixtures containing brewer's grain will spoil quite rapidly, so any excess feed that animals have not consumed should be removed and discarded. The palatability of wet brewer's grain will decline with increasing storage time.
Dried citrus pulp is available from the citrus industry and approximately 600,000 ton are produced annually in Florida. About 90 percent is pelleted and approximately 70 percent of total production is marketed outside the United States. Other countries also produce high levels of citrus pulp as well. The nutrient content of citrus pulp is influenced by several factors including source of fruit and type of processing. It is considered a bulky concentrate being high in energy, low in protein and fiber but with some roughage replacement value. Citrus pulp is well utilized by ruminants when fed at levels which do not exceed 30 percent of total DMI. Citrus pulp is a valuable commodity for feeding dairy cattle since it provides an good source of soluble fiber.
Citrus Pulp is the dried residue of peel, pulp and seeds of oranges, grapefruit and other citrus fruit. As with most feeds, citrus pulp is dried to a moisture content of approximately 10 percent although some wet product is available. Dried Citrus Pulp is second only to corn as a source of concentrated feed nutrients for dairy and beef cattle, and sheep. It is a good source of calcium, but very low in phosphorus and carotene (precursor for Vitamin A). Based on these data, dried or pelleted citrus pulp is one of the most desirable energy feeds and can be considered in feeding programs as having the following characteristics:
• A dry carbohydrate concentrate with high total digestible nutrient (TDN) content averaging about 74 percent
• A bulk energy feed with a high degree of water absorption
• Having an above-average palatability for cattle.
• As a general rule, 40 – 45 percent of the ground corn in a dairy ration can be replaced by dried citrus pulp or pellets.
Table 2. Typical Analysis
Much of the original research that developed dry citrus pulp as a cattle feed was conducted in the 1940s and 1950s. Subsequently, dry citrus pulp became a hot commodity on the European feed market and was priced out of reach to the beef industry. Recently, the European market softened and dry citrus pulp is again affordable in Florida and some areas in the south as a winter supplement.
Considerations for the Use of Wet Citrus Pulp
If the market price of dry citrus pulp is low, the cost of processing dry citrus pulp may exceed its value as a commodity feed. Therefore, many citrus plants discontinue processing dry citrus pulp and offer wet pulp to cattlemen for the price of trucking. While this may sound free, but it is not. Wet pulp contains approximately 80 percent water, and trucking water to livestock is not a profitable endeavor. Therefore, the value of wet pulp must be weighed against the cost of dry pulp or other feed supplements. First it is assumed that dry and wet citrus pulp have the same nutritive value on a dry matter basis; 78 percent TDN and 7.0 percent protein. If a truck delivers 15 tons of wet pulp for $100 it cost $7/ton of wet pulp which appears cheap, but since wet pulp contains only 20 percent dry matter the real cost is $33/ton of dry matter. In comparison dry pulp containing 91 percent dry matter, at $55/ton, has a value of $60/ton of dry matter. Even though wet citrus pulp is free, the cost of shipping significantly affects the actual cost to the producer.
Another consideration is that cows will waste a considerable amount of wet pulp offered free-choice in a pile. Compared to a waste of 5 percent with dry pelleted pulp, wet pulp waste could be as high as 30 percent. Using these assumptions on waste, dry citrus pulp would cost $64/ton of dry matter consumed, and wet pulp would cost $48/ton of dry matter consumed. In the above example, wet citrus pulp remains a good buy, even when adjusted for its high water content and high wastage. However, this example shows that a feed product like wet citrus pulp that appears cheap on an as-fed basis can be relatively expensive in terms of real costs when consumed by the cow. Thus, it is important to be careful what one pays for wet pulp.
Feeding citrus pulp should be viewed as a complement to a good winter forage program. Citrus pulp is low in fiber and protein which are needed by the cow for good nutrition. It is important that adequate quantities of forage be availability and a good protein supplement be provided when feeding either dry or wet citrus pulp, especially for young cattle.
Pasture sod damage will occur in the feeding areas used to pile wet pulp. In these areas pasture weeds and undesirable grasses may become established the following growing season. To minimize this problem, place wet pulp on less productive areas of pasture and continue to dump new loads in the same location. Obviously another alternative is to feed the product in troughs.
Once more we see by-product feeds can have a lot of value in the feeding of beef cattle. We also see, again, that considerations have to be given to how it must be handled and factors to be aware of. In the next issue we will conclude this series on the evaluation of by-product feeds. Given the number of by-products and the emergence of more all the time, we could continue this series for quite some time. Time to go on to bigger and better things.
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 email@example.com.