By John Paterson, Rick Funston and Ron Carlstrom, Montana State University, Bozeman; and Greg Lardy, North Dakota State University, Fargo
06/06/00 BOZEMAN -- Drought-affected pastures and native range generally do not produce adequate forage to maintain "normal" stocking rates, so producers must provide supplemental energy to meet the needs of the cow herd. Producers generally have two options to meet nutrient requirements of cattle on drought affected pastures and ranges. The first is to provide supplemental feed for adequate energy, protein, vitamins and minerals. The second is to reduce the nutrient requirements of the cow to a point where they can be met with available forage.
If you supplement hay on range land, try not to buy or harvest weed-infested hay. The future cost of feeding weed-infested hay far out-weighs its feed value in the short-run. If weedy hay must be fed, feed in an area or holding pasture that is removed from streams, riparian areas and wooded areas. Keep cattle confined for several days after feeding weedy hay to prevent spreading viable seed from their digestive tract. Observe holding pastures and feeding areas closely, and treat weed infestations. Try to take advantage of areas dominated with annual species. They should be grazed early in the season when their nutrient value is high. This will allow grazing deferment on the higher-condition range dominated with perennial plants.
Crop residues such as small grain straws are important ways to stretch tight feed supplies.
Pastures and native range that are dormant due to drought may be low in vitamin A, phosphorus and protein. Meeting the need for these nutrients is important to maintain herd productivity.
Reducing the stocking rate helps range plants by reducing stress and also provides more forage for remaining cattle. When stocking rates are reduced in accordance with production, only small effects on weaning weight may be noted. If stocking rate is not reduced, supplemental feeding is necessary to maintain herd productivity and alleviate grazing pressure.
Minerals. Provide the same salt and mineral mixture during drought as you would normally. However, during drought phosphorus supplementation is even more critical. A complete mineral supplement containing 12 percent calcium, 12 percent phosphorus, 5 percent magnesium, 0.4 percent zinc (4000 ppm), and 0.2 percent copper (2000 ppm) has worked well in many areas. The mineral supplement should be placed close to stock-watering locations.
Vitamin A. Lack of vitamin A may become a problem during the fall and winter for cows that grazed drought-affected pastures during the summer. Vitamin A is lacking in forages growing under drought and hay produced from drought-affected forages. Cows should receive vitamin A and D booster shots about 30 days prior to calving if they have not been previously supplemented with vitamins.
Protein. Pastures dormant due to drought may be deficient in protein. If this occurs during the breeding season, reductions in pregnancy rate can occur. Provide dry cows with about 0.5 - 0.75 pounds of supplemental crude protein and lactating cows with 0.9 - 1.2 pounds of supplemental crude protein per day. This can be fed as about 1.0 - 1.5 pounds of soybean meal for dry cows and 2.0 - 2.5 pounds of soybean meal for lactating cows. Feed one pound to two pounds per day of a high protein supplement to dry cows and possibly as much as two pound to three pounds to lactating cows to maintain forage intake and efficient use of forage.
Protein supplementation may be necessary for optimum breeding rates during drought. Oil-seed meal supplements (cottonseed meal, soybean meal and canola meal), commercial protein blocks, liquids and tubs would also be appropriate. Alfalfa hay, sunflower meal, safflower meal and other protein meals may also be used as protein supplements.
Energy. During drought, energy may be the most limiting nutrient for grazing cattle. Hay, grain and crop processing byproducts can supply energy to cattle. Low-quality forages can be ammoniated to increase digestibility and protein.
Grain supplementation on pasture can result in a "catch 22" problem. Excess supplemental grain can reduce forage intake and digestibility, resulting in less energy available to the animal from available forage. As a rule of thumb, up to 0.2 percent of body weight of supplemental grain per head per day will not result in large decreases in forage intake and digestion. For example, a 1,200-pound cow could receive 2.4 pounds of grain per day without drastically reducing forage use. For some grains, processing may be necessary for optimum use by cattle. Corn and oats can be fed whole but may be used better if coarsely rolled before feeding. Barley and wheat should be coarsely rolled. Avoid fine grinding and rolling, which results in excess fines and dust. These can result in increased incidence of acidosis and founder. In addition, extremely dusty supplements are unpalatable. However, the producer must weigh the additional costs of processing vs. the value of the grain. Grain processing co-products such as wheat midds, soybean hulls and corn gluten feed which contain highly digestible fiber provide energy while alleviating much of the negative impact that grain supplementation has on fiber digestibility. In addition, these byproducts provide protein which may also be limiting in drought stressed forages. When using by-product feedstuffs, make sure that the mineral program is balanced. These feeds are typically high in phosphorous and potentially high in sulfur, which may lead to some mineral imbalances. The trace mineral levels may be somewhat low as well.
Drylot Feeding. If pasture are very poor, producers may consider feeding cows in drylot. This may be more cost effective than supplementation on range if large amounts of supplement must be transported and fed. In addition, it may allow pastures to begin recovering from drought.
When pasture is lacking in amount ands quality: If only slightly limited, the feeding of range cubes (minimum 20 percent crude protein) or mixtures of grain and cottonseed or soybean meal at rates of 3 - 5 pounds per cow daily may work for a while. Cubes with a large amount of natural protein and a low crude fiber level (less than 10 percent) would be preferred.
When pasture becomes extremely short, purchase of hay or replacement feed must be considered as well as selling stock. Most grass hay has only 50 to 65 percent of the energy of grain, so one pound of grain can replace 1.5 - 2.0 pounds of hay or 1.2 - 1.4 pounds of alfalfa hay. It doesn't make sense to pay $105 per ton for poor quality grass hay when grain would cost very little more. It is necessary to start cows on grain slowly and feed so that all cows get their share. You can feed up to 80 percent grain in a maintenance diet for British bred cows, but such high levels should not be considered for Brahman cattle. All cattle need some forage in the diet to minimize digestive problems.
Lactation represents the greatest nutrient demand for cows over a yearlong production cycle. Lactation increases demand for energy, protein and other nutrients. A simple ways to reduce nutrient requirements is to wean the calf. This can cut nutrient requirements by one-third to one-half depending on the cow's milk production. Early weaned calves can achieve adequate rates of growth if given access to a high quality ration. Dry cows will eat less forage and usually travel further distances to forage than lactating cows. By removing lactation, acceptable pregnancy rates and calving season length can usually be maintained.
Unavailability of feeds or unusually high cost often prohibits feeding lactating cows the nutrients necessary for lactation and rebreeding. To reduce stress and lessen feed, the only thing that can be removed is lactation. Calves can be weaned after 60 - 80 days of age, or partially removed by creep feeding. If weaning part of a herd, logical candidates for early weaning are cows nursing first or second calves, since these cows have nutrient requirements for growth in addition to maintenance and lactation. Nutrient requirements for lactation and growth are given higher priority than reproduction. By removing lactation nutrient requirements, growth and reproduction receive a more of the nutrients available.
Production requirements of the mature cow for which nutrients are needed include body maintenance, lactation and rebreeding.
Feeding Management Options:
Feeding ammoniated straw may be an option during drought. Sixty pounds of anhydrous ammonia per ton of straw will increase cattle performance and make it possible to use wheat straw as the only roughage in the diet, something not recommended for untreated straw. A summary of four trials shown in the following table indicates that actual daily gain was improved by ammoniation by 0.31 - 0.82 pounds daily.
Table 1. Summary of Daily Gain Results Using Ammoniated Wheat Straw
Gain improved because of increased digestibility and intake. Two to 3 pounds of supplement or alfalfa hay were fed with free choice ammoniated wheat straw. Ammoniation alone does not make wheat straw a complete feed. A good mineral/vitamin supplement is essential and supplementation with 1-2 pounds of natural protein is needed with the nonprotein nitrogen added by ammoniation. Toxicity problems, involving calf losses and wild irrational cattle behavior, have been reported when ammoniating high-quality forages, but not with ammoniated wheat straw or similar products.
Stay alert for potential problems that might be a result of drought:
The use of salt to limit supplement intake may increase water intake 50 - 75 percent. Water must not be limited in any way or salt toxicity may result.
Over-consumption of urea-containing supplements by cattle on forage scarce ranges may result in ammonia toxicity. Generally, cattle performance on urea-type supplements can be lower than expected when energy or forage is in short supply.
Hay cut under moisture stress, especially grain type hays, may contain high levels of nitrate. Test a representative sample for nitrate before feeding such hays.
Prussic acid or cyanide poisoning can also be a problem on drought-stunted plants such as sorghum, sorghum hybrids and sudan grass. If forage for hay is allowed to sun cure thoroughly for three to five days, bleaching out any bright green color, prussic acid problems should be lessened.
Cattle grazing short pasture are more likely to consume poisonous plants.
Alternate day feeding of protein supplements (> 30 percent crude protein), like oil-seed meal cubes, has been recommended to save labor. The practice is still good for high protein supplements but is not to be used for grain type supplements. High energy supplements (grain, breeder cubes, etc.) should be fed daily especially where ³ .5 percent of body weight may be fed daily. High-energy acid-producing feeds tend to decrease rumen pH and fiber digestion and alternate day feeding of large amounts simply magnifies the decrease in rumen pH. Furthermore, unadapted cows should be started on grain feeding slowly or the problems of acidosis, founder and even death may result.
Rumen impaction may result where cattle receive inadequate protein (less than 7 percent to 8 percent CP in total diet) and too much of a low quality/high fiber forage such as drought pasture or wheat straw only. Lack of adequate water will aggravate the impaction problem.
"Hardware disease." Hay harvested from vacant city lots, roadsides etc., may contain nails, wire or foreign objects which can pierce the rumen wall resulting in death of the animal. Close observation of feeds and the use of magnets in grinder/mixers can help to reduce the potential consumption of problem materials by animals.
Drought develops progressively and not overnight. Management of the ranch during a drought depends on the balance between stocking density and the availability of feed and water. In the long run, you can help protect your interests by sound planning to make your ranch decisions less sensitive to drought. Early decisions need to be based on what relief measures are potentially available on the ranch. Among the important factors are guessing the expected duration of the drought, the current water and feed inventories, the body condition of the cowherd and financial resources available. During drought, decisions may often be made on emotion rather than logic. The main goal is to make objective decisions and get skilled help when necessary from your county agent, beef specialist or agricultural consultant.
The sources of information for this manuscript are from the following: Montana State University, North Dakota State University, Texas A&M University, Penn State University, Queensland Beef Industry Institute, and NSW Agriculture.
Send questions or comments to Carol Flaherty, MSU Communications Services, Bozeman, MT 59717 or to Flaherty with this link: firstname.lastname@example.org.
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