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Vets can help with drought-stressed cattle

Your veterinarian can help stretch the limited feed supply and improve efficiency of beef production.

Scott Poock, a University of Missouri Extension veterinarian, is already headed in that direction, helping herd owners see the possibilities.“The drought gives extra incentive to do what ought to be done every year,” Poock says.

His most immediate concern is to make sure toxic— high-nitrate, that is — forage isn’t fed to cow herds.“The vet pathology lab is seeing lots of samples of high-nitrate corn being ensiled,” he says. “It’s important to also test feed when it comes out,”

Silage making will reduce the nitrate. But, just make sure enough was removed to make a safe feed. Producers realize the dangers of high nitrates. Cattle that turn up their heels are very visible. The unseen loss is likely more costly. Nitrates can cause lost pregnancies.

Now, we’re getting close to Poock’s greatest concern, the impact of drought on reproductive efficiency.“Just expect that we are going to have lower conception rates.” Poock says. But, he lists many ways to improve chances for making calves for next season.He starts with some easy ones. Make sure vaccinations and de-worming are timely — before the fall breeding season.

A month before breeding use modified live vaccines for bovine viral diarrhea, or BVD, infectious bovine rhinotracheitis, or IBR; and leptospirosis, or lepto. The shots must be given 30 days in advance, so the immunity is built up. Vaccinations just before breeding can lower conception rates.

BVD becomes more important to prevent persistently infected, or PI, cows in the herd. “We’ve had more cows moving in and out of the state” Poock says. “It’s harder to maintain closed herds.’

To develop the best immunity, the vaccines should not be given to heat-stressed cows. Wait until temperatures drop; don’t vaccinate on 90-degree F days.Proper protocols can prevent fetal losses: losses not known until too late.

Worming after a drought becomes more important. “In hot, dry weather worms kind of hibernate,” Poock says. “At the first rains in September, you get the grass growth, but also a flush of worms returning. “You get more exposure than you think possible.”

All of these tips also indirectly affect efficiency of use of available feed. Feed cows, not worms.

Timing of worming is critical for best control Wait about three weeks, after rains come and grass growth starts. “You want the worms to be big enough for the wormers to work.” If you worm too early, you’ll have to do it again, Poock says.After the hot summer, cows will need time to recover and start cycling before the fall breeding season.

For lots of reasons, Poock believes timed artificial insemination can help improve conception rates.The frozen semen was probably collected last winter, and will be viable if it is from a major AI stud. Once it is in the freezer, it is “good forever.”

The use of controlled internal drug release, or CIDR, devices to synchronize the cows, also will jump-start the cycling of cows coming out of drought stress. “The progesterone in the CIDR insert will get cows to cycling that might not cycle in time for breeding.”

Poock likes the Show-Me-Synch AI breeding protocol. This has the 14-day CIDR. That stretches out the pre-breeding protocol to 33 days.

That early start allows doing a lot of the vet work upfront: Vaccinations, de-worming and inserting CIDRs. “It just means fewer trips through the chute, less handling.”Here’s the big step in improving efficiency: Ultrasound the bred cows 70 to 90 days after the timed AI.

It’s not unlikely to achieve 60% pregnancy with the AI, and 25% with the cleanup bulls. That leaves 15% probably open. “Sending those to market makes a big difference in the winter feed bill. You will be using your feed on cows making money.”

That’s important with short supply of costly feed. “But, my bias is that this should be done every year.”Even moving those cows that might be pregnant helps tighten up the calving season. That pays as well.

Particularly for the dairy herds he works with, Poock recommends using the pregnancy checks to tighten up the milking season. “If you’ve got 10 cows that are late calvers, move ’em out. That allows ‘investing’ feed in cows that will make the best return-cows that calve early — and likely to rebreed early.”

With the likelihood of reduced conception rates after a stressful summer, Poock says to give extra attention to nutrition.There’s a greater chance for the forages to be lower in protein and energy. Forages should be tested not only for nitrates, but also for nutrients.

A balanced ration can help cows gain weight and body condition. That’s important before calving and before breeding. After calving, to make milk, cows need protein. Poock is particularly concerned about feed for yearling heifers coming into the herd. “Put a little more feed into them this year,” he advises.

Heifers should gain weight not only through AI breeding season, but also during cleanup season. “Too often, after the heifers get through the first breeding cycle, producers think, ‘Oh they are in good shape,’ and let up on the feed,” Poock says. “They need to be on more than a maintenance diet.” They need to be gaining condition to achieve conception, and maintain it.

The veterinarian urges extra attention to the reproductive health of the herd. Skimping on getting ready for payday doesn’t pay.

Heat-stressed bulls Need recovery

Bulls are going to be hard-pressed to do their job in the fall breeding season. The longer the hot weather lasts, the longer the delay on return of viable semen.

The bull examination should be delayed. Hot weather, over 95 degrees F, shuts down the viable semen. “It will take 70 days for the semen to recover after the last heat stress,” says Dr. Scott Poock, a University of Missouri Extension veterinarian.

If breeding is intended for after Thanksgiving, wait until early November for the semen check. “Give the bulls a chance to cool down and recover from summer.”

The bulls, turned in with cows for cleanup after timed AI, also gain more time to recover. Poock cautions that extra bulls may be needed this fall. “If the conception rate is not as high as usual, there will be more cows, all synchronized for their second cycle.

“One cleanup bull might not be enough,” Poock speculates.


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This article published in the September, 2012 edition of MISSOURI RURALIST.

All rights reserved. Copyright Farm Progress Cos. 2012.