Managing cow herds during drought

Source: University of Nebraska

Anytime drought occurs, times are difficult for livestock producers. However, avoid management practices that would lead to “panic”, mass selling of livestock. Our comments for your consideration are as follows.

1. Calves could be early-weaned. Take the calves to drylot and feed for normal growth. Guidelines can be found in NebGuide G2047 “Management of Early Weaned Calves” (PDF version, 283KB).

   Dry cows could then be maintained by grazing poor quality pastures or fed low quality feeds until crop residues are available. In early gestation, dry cows can be maintained on low quality feeds without long-range effects on reproductive performance. For each 2.5 days that the calf is weaned there is 1 extra day of forage available for grazing.

2. If the drought continues, cows will be culled and cow prices will undoubtedly decline. If adequate sources of feed are available, we would advise not to cull until after pregnancy test. Pregnancy check no earlier than 35 to 45 days after the end of the breeding season.

   If producers are to cull cows, use the following criteria:
   ·  Cows with physical impairments.
   ·  Non-pregnant cows – after accurately pregnancy testing.
   ·  Old, mature cows.
   ·  Cows with low production records.

   If the breeding season for the cow herd is close to ending producers may want to wait and cull cows on a pregnancy test basis. Pregnancy check approximately 50-60 days after removing the bulls from the breeding pasture for accurate results using rectal palpation. For experienced ultrasound technicians, pregnancy detection after about day 30 to 35 of pregnancy is about 100 percent accurate.

3. When late summer pastures are used up and cow and calf prices are low, and creep feeding or early weaning the calves is too expensive to consider due to high grain prices, a management alternative may be feeding cow and calf pairs a forage:distillers grains combination in a dry lot or a pasture converted to a dry lot. Forages possibilities would be ammoniated wheat straw, small grain hays such as oat or wheat hay (be aware of nitrates), or corn stalk bales carried over from last year. In this feeding scheme, the calves would remain on the cows and it is assumed that the breeding season is over. This would give producers an opportunity to take advantage of marketing the calves later in the year.

   Ammoniated wheat straw works well in beef cow diets.

   Crop residue combined with byproducts may be an option for cows grazing pasture or in a dry lot. Distiller grains are usually less expensive in the summer. For more information, please see NebGuide G2099: Crop Residue or Low Quality Hay Combined with Byproducts as a Forage Substitute (PDF version, 303KB).

   If the prospective supply of winter forage is not sufficient to maintain the usual number of cows and replacement heifers, considerable thought needs to be spent on whether to cull cows of producing age or heifers being kept for replacement.

   The amount of feed required to keep heifers developing will be slightly less than that needed to winter a mature cow. The lesser amount of feed may be offset by the heifer’s nutrient need for better quality feed during the first winter.

   Unbred heifers will not be producing a salable product in the next year, of course, so any feed used for them this fall and winter will not help generate any income, for more information: http://beef.unl.edu/cattleproduction/ammoniatingcropresidues.

4. Annuals can be used to provide forage with limited irrigation. For more information see Utilizing Annual Forages with Limited Irrigation for Beef Cattle During and Following Drought, NebGuide G2185 (PDF version 1.09MB) Nitrates can be a concern for summer annuals grown in drought conditions. Ensiling forages can result in a 40 to 60 percent decrease nitrate concentrations and thus can be used to deal with higher nitrate feedstuffs. For more information, please see Managing Nitrates in Annual Forageshttp://beef.unl.edu/cattleproduction/nitratesinforages Problems concerning prussic acid are generally associated with lush growth of the plant. Most plants that are 18″ tall and dying back cause few prussic acid problems; however, a rain may cause growth of secondary shoots that could cause problems.
5. If the drought continues long enough to cause drastic reductions in grain yields, this may result in an increase in the number of acres cut for silage. As for the cow herd, this may reduce the acres left for cornstalk and milo stubble grazing. If this happens, be prepared to feed cows, after the calves are weaned. Silage would be a possible feed that could be fed to the cow herd the last 60 days of gestation and then after calving.
6. Corn stalk grazing after harvest is a good feed resource for beef cows. Although yields may be reduced, there is likely residue available for grazing. The amount of residue remaining is a function of grain yield. If there are any nitrates, they will be in the bottom 8 inches of the stalk. The stalk is usually the last component of a corn residue field selected. Cows will select any grain or corn ears in the field first, followed by the husk and leaf, and finally the cob and the stalks. For more information, please see Extension Circular EC278: Grazing Crop Residues with Beef Cattle (available for purchase on the UNL Marketplace – $2.50).

Dr. Rick Rasby
Professor of Animal Science
Animal Science, University of Nebraska – Lincoln, Lincoln, NE