Managing Cattle In a Drought

June 17, 2011 By Robert Fears

Parts of many countries are currently under drought including Canada, China, Mexico, United Kingdom, the United States and others. These continued droughts make it tough for cow/calf producers to survive financially; however there are management techniques that might help. The most important practice in drought management is to avoid overgrazing pastures to the extent that their recovery is prolonged when it does rain again.

“The road to recovery is much longer if pastures exit drought in poor condition,” states Rocky Lemus, extension forage specialist at Mississippi State University. “When drought comes and forage is in short supply, it is tempting to graze pastures to bare ground. Pasture plants need rest from grazing to restore their energy reserves. Reduced plant growth during drought causes pastures to require longer rest periods for survival. Cattle should not return to the pasture until grass regrows to a height of eight to ten inches. Increasing grazing stubble height helps shade and cool the soil. Moisture is conserved by reducing evaporation and making scarce moisture more effective. Maintaining an adequate amount of stubble or residue will also encourage root development below the soil surface. Use of rotational grazing improves forage utilization and can prevent spot grazing that causes trampling and wasting considerable amounts of forage. Subdividing pastures into smaller units with portable electric fences is cost effective if proper stocking rates are utilized.”

The Samuel Roberts Noble Foundation, headquartered in Ardmore, Oklahoma, recommends a forage inventory estimate and a determination of whether herd size should be reduced. If destocking is necessary, it should be done in phases to coincide with forage supply decreases. Phase 1 is reducing stocking rates by moving part of the herd to leased pasture. In Phase 2 all open cows and inferior bulls are sold. Heavy calves are either sold, moved to a pre-conditioning facility or custom fed in a feed lot.

Sell low or poor producers and older cows during Phase 3. Non-conformers, such as cows calving late or irregularly and cows with poor disposition, are sold during this period. It is also a good time to sell cows that are not uniform with the rest of the herd such as color, frame size, polled and other features.

As you enter Phase 4, culling decisions become tougher. This is the time to cull replacement heifers and old cows even if they are still good producers. The most productive cow herd is usually composed of five- to eight-year olds; so culling on each end of this age bracket will leave a productive herd to rebuild cow inventory after the drought.

Weaning calves at four or five months of age instead of six to eight months is another drought management strategy. Lemus explains, “Mature cows might have the ability to survive better than young livestock that are still growing. Dry cows usually consume about 35-40 percent less forage than lactating cows and calves under 500 pounds consume about 33 percent as much as mature cows.”

Lemus recommends not applying fertilizer to pastures when soil moisture is lacking. He says, “Enough soil moisture should be present to keep fertilizer nutrients in solution for increased plant root uptake. Under drought stress, plants tend to increase nitrate accumulation that can cause nitrate poisoning in livestock. This is very common in plants such as Johnsongrass, sorghums, sorghum-sudangrass, pigweed and lambsquarter.”

Perennial weeds tend to thrive during drought because they are deeper rooted than grass and clover and can use soil moisture that is unavailable to the more shallow rooted plants. Although weeds compete with desirable pasture plants for sunlight, soil nutrients and water, use of herbicides during drought is usually not effective. Low moisture in most cases prevents entry and translocation of herbicides into the plant.

It is important to retain pasture plant vigor and health to accelerate post-drought recovery. Some of the ways to do this is to change weaning times, alter culling practices and use proper pasture management techniques.