June 13, 2002

Cattle on Drought Stressed Pastures May Need Supplements, Beef Specialist Says

Poor pastures resulting from paltry precipitation in some areas of the region this spring have producers scrambling to meet the nutritional needs of cattle.

"With some areas of the region seeing extremely poor pastures, producers are going to have to work hard to keep cattle in good condition," says Greg Lardy, beef specialist with the North Dakota State University Extension Service. "There are generally two options: reduce the nutrient needs of their cattle or provide supplemental feeds."

Lactation places the greatest nutrient demand on cows during a production cycle, Lardy notes, increasing the need for energy, protein and other nutrients. "One of the simplest ways to reduce nutrient requirements is to wean the calf. That can cut nutrient requirements by one-third to one-half."

Early weaned calves can achieve adequate rates of growth if given access to a high quality ration. At the same time, the reduced nutrient needs of dry cows may be able to be met with existing pastures or limited supplements. "By removing the demands of lactation, you can limit the amount of feed needed to maintain acceptable pregnancy rates and calving season length," Lardy says.

"One option may be to wean only a portion of the herd," he notes. "Logical candidates would be cows nursing their first or second calf. Those animals are continuing to grow even as they provide for their offspring so it’s more difficult and important to provide adequate nutrition."

If nutrient needs can’t be reduced enough to be met with existing pastures, producers may need to provide supplemental feeds. Key nutrients will be minerals, vitamin A, protein and energy.

"During drought conditions, energy may be the most limiting nutrient for grazing cattle," Lardy says. "Hay, grain and crop processing byproducts can all be used to supply energy to grazing cattle. Low quality forages can be ammoniated to increase digestibility and protein content.

Grains can be used to supplement sparse pastures, but they can result in a "catch 22," Lardy notes. "Too much grain can reduce forage digestibility, resulting in less energy available to the animal."

In general, up to 0.4 percent of body weight of supplemental grain per head per day will not result in large decreases in forage digestibility. For example, a 1,200 pound cow could receive 4.8 pounds of grain per day.

For some grains, processing may be necessary for optimum use by cattle, Lardy says. Corn and oats can be fed whole but corn may be utilized better if coarsely rolled. Barley and wheat should be coarsely rolled. With barley, crack the hull. With all grains avoid fine grinding and rolling, which results in excess fines and dust.

Grain processing coproducts such as wheat midds and wet corn gluten feed contain highly digestible fiber provide energy while alleviating much of the negative impact that grain supplementation has on fiber digestibility. In addition, these coproducts also provide protein.

Lardy notes that self-fed grain or protein supplements can be limited with salt. In general, cattle will consume up to 0.1 percent of their body weight in salt. Add salt to the ration at a rate to obtain the desired intake of concentrate.

For mineral supplements, Lardy advises producers to provide the same salt and mineral mixture during drought as they would during normal conditions. During drought, phosphorus supplementation is especially critical so a mixture of 50 percent trace mineralized salt and 50 percent dicalcium phosphate supplied free choice to the cow herd will meet the phosphorus requirement. Place the salt mixture near watering locations.

A lack of vitamin A may become a problem in the fall and winter for cows that grazed drought affected pastures in the summer. "Vitamin A is lacking in forages grown under drought conditions and hay produced from drought-affected forages," Lardy says. "Give cows vitamin A and D booster shots about 30 days before calving and calves should receive vitamin A and D at birth."

Similarly, pastures dormant from drought conditions may lack protein. "If the conditions occurred during breeding season, you may see reductions in pregnancy rates," Lardy says. "Alfalfa hay, sunflower meal, safflower meal as well as other protein meals can be used as supplements." Provide dry cows with 1/2 to 3/4 pound of supplemental crude protein per day. Lactating cows should receive 1 to 1 1/2. Pounds of supplemental crude protein per day.

"If you’re making adjustments to the diet, do so slowly and keep a close eye on your cattle," Lardy advises. "If your cattle are stressed from trying to feed under drought conditions you don’t want to complicate matters with a case of acidosis."

For more information on managing livestock and crops under drought conditions, go to http://www.ag.ndsu.nodak.edu/drought/drought.htm. 

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Source: Greg Lardy, (701) 231-7660, glardy@ndsuext.nodak.edu
Editor: Tom Jirik, (701) 231-9629, tjirik@ndsuext.nodak.edu

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