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Reduce Long-Term Impacts of Drought On Your Herd’s Reproductive Rate

Zinc, copper, selenium, Vitamin A and other micronutrients are likely deficient in cattle coming out of a severe drought.

November 26, 2012

6 Min Read
Reduce Long-Term Impacts of Drought On Your Herd’s Reproductive Rate

After a drought year everyone wants to forget, processing time can help cow-calf producers evaluate the mature weights and body condition scores of cows to help avert long-term damage to a good breeding program, says a leading beef cattle specialist at Kansas State University.

Bob Weaber, K-State Extension cow-calf specialist, says this can help ranchers determine which changes may be needed in their supplement feed program and whether non-performing females need to be culled before additional money is spent.

Dr. Doug Ensley, Professional Services Veterinarian (PSV) with Boehringer Ingelheim Vetmedica, Inc., adds that early detection of problems before it’s time for cows to begin cycling can help keep calving rates from dropping drastically after the summer’s dry, hot weather has taken its toll on cows.

“The biggest threat to long-term reproduction from cows is the lack of good forage and energy during the drought that can impact their ability to cycle,” Ensley says. “Poor forages may be low in trace minerals which can lead to a reduced ability to cycle reducing the ability to breed back and have a live healthy calf.

“You could start seeing herds with 50-60% pregnancy rates. You need to build up their internal fat and overall body condition to help get them cycling on a regular basis.”

Focus on nutrition

Zinc, copper, selenium, Vitamin A and other micronutrients are likely deficient in cattle coming out of a severe drought. “Those need to be part of a good forage, supplement and mineral program,” Ensley says. “We need to be good grass farmers and do a good job of testing forage and what we’re using as a supplement.

“Feed is 65% of the cash cost in maintaining a cow. You can hold costs down by testing what you feed. We receive a lot of calls from ranchers who are seeing high nitrates (potential carcinogens) in their hay. So test to make sure you’re not feeding nitrates, especially in drought areas.”

Most regional Extension outlets provide forage-testing services. Private forage consultants can also provide the service. “Also, look at your mineral program,” Ensley advises, “the whole micro-mineral, not just salt.”

Rangeland specialists also recommend that producers give pastures plenty of time to replenish the surface forage, as well as the root system so plants can take advantage of soil nutrients. A good fertilizer program may be needed to restore nutrients lost during a drought. And a good herbicide program may be needed to control weeds that will rob precious grasses of rainfall and snow when it finally comes.

Don’t forget about bull nutrition. “Drought is going to affect their production of semen,” Ensley says. “Like with cows, keep their body condition score (BCS) in the 5-6 range. It’s like a broken record. Don’t let them get too fat. Again, semen quality can go down. Don’t wait until a week before breeding to check them.”

Culling decisions

Weaber says spending a little extra time to identify problem cows will improve a cow-calf program. “If you find that you need to further reduce your cow inventory due to drought, do it in a strategic way,” he says. “Evaluate them for pregnancy status, udder quality and adequacy of teeth and feet structure.

“Strategic culling plans should be developed to first cull cows that are least productive to conserve as many ‘good’ cows expected to be entering their prime producing years as possible. Open cows should be marketed in a timely fashion to reduce nutrient demand if you are in a drought condition.

“Cull cows with poor udder quality or dry quarters. Also cull cows with no teeth or worn teeth. These should be followed by old cows that are at or near the end of their productive life. Next, consider selling open and bred replacement heifers. Culling these females, although they represent the newest genetics in your herd, will reduce overall herd nutrient demands above just maintenance requirements, as they are still growing.           

“However, if the open cows are thin and you have grazing pasture or feedstuffs available, consider feeding supplement to the cows to regain some condition before marketing. This will generally increase sale weight of cows and the price received for them.”

Weaber says conserving cows that are expected to be most productive will set up future marketing opportunities of future calf crops on markets that are expected to be short on supply and strongon demand resulting in high calf prices.

But after drought, those females may need a revised nutritional and animal health program to achieve their fullest ability to produce a good calf.  Ensley says obtaining a female BCS of 5-6 is essential in overcoming the impact of drought.

“One of the easiest tools for most producers is to get females into the 5-6 range to go into breeding,” he says. “The ability to cycle will be less for those cows that are below 5 BCS. They need to be in a positive energy balance going into the breeding season.”

 Weaber notes that cow weights alone are not particularly good indicators of energy reserves. BCS is a subjective method that helps estimate differences in body weight and fat composition.  Cow weights should be corrected for both age and BCS.

“The Beef Improvement Federation provides guidelines on adjustments of these records to a constant BCS of 5,” he says. “As a general rule, each full score is equivalent to approximately 80 lbs. of live weight. For example a 1,200-lb. cow in BCS 4 would adjust to a 1,280-lb. cow at BCS 5.

“Mature weights should be used in computing nutrient or forage requirements for the coming months to assure you’ll have adequate feed on hand.”


A good nutritional program will help expedite the breeding cycle of females bought as replacements for cows liquidated during a drought. Stan Bevers, Texas AgriLife Extension economist in Vernon, Texas, says producers looking for replacements often select young females, two to three years old, for longevity. But that may not be the correct decision if you want a calf next year.

“We know that those females don’t have the highest probability for reproduction in the near term,” he says. “A middle-aged female probably has a higher calving probability than either a younger female or an aged female.”

When replacement heifers are worked into a herd, Ensley says they should be fenced off from older cows. “Keep them isolated, get their health status to where it needs to be,” he says.  “You want to get them on the same health program your cows are on, but try to keep them separated from mature cows.  If not, you know who is going to beat out whom at the feed bunk.  Heifers won’t get nutrition they need.”

Develop a drought plan

Prevention of long-term effects on a cow-calf operation should include early planning, says Denise Schwab, Iowa State University Extension beef cattle specialist.  

“Develop a plan before the drought conditions get any worse,” Schwab says, adding that the plan should provide for emergency feed in the short-term, as well as winter feed in the longer term. “This requires an inventory of feed currently available and an inventory of the cowherd.

“You can often purchase hay less expensively during the growing season than in the winter. You also have the option now to incorporate silage into your winter feed supply.”

Unfortunately, recent drought years have provided unwanted on-the-job training to many. But lessons have been learned. Weaber encourages producers to seek additional information from their consulting veterinarian or nutritionist and from Extension to learn more about how to limit the impacts of drought on a herd.

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