Veterinarian offers tips to care for high health risk cattle
By Kylene Scott
Three of the most inconsistent things in the world are cattle, weather and people. Dr. Dan Thomson said a cattle feeder once told him that, and he believes it.
Working as a veterinarian in the feedlot industry for a number of years, and now at Kansas State University College of Veterinary Medicine, Thomson understands the pressures cattle feeders face. He spoke at the K-State Cattle Feeders College at the Haskell County Fairgrounds, Sublette, Kansas, May 22.
“Understanding what the pressures of what you all are going through and some of the things that we deal with on a day-to-day basis is something that I’m very, very aware of,” Thomson said.
As a solo practitioner, Thomson used to start thousands of cutter bulls each fall. Along the way he learned a couple of things. First, don’t get your expectations too high.
“One of the things that always amazed me when we’d get a group of calves in is that we would have the expectation that none of these is going to die. We’re going to save them all,” Thomson said. “Our expectation is zero death loss, and we’re going to go through some of that, then understand it’s just not possible.”
In order to manage high health risk cattle, feeders must first understand a couple of things, and those include: deciding if it’s a morbidity problem or a case fatality problem, commingling, transportation issues, adding on to pens, receiving and processing, vaccinations and treatments, and nutrition.
When a feedyard has a high death loss rate, it must be determined whether it’s a morbidity problem or a case fatality rate problem. Often, the cattle had something going on before entering the feedyard, and Thomson said he sometimes hears cattle feeders say, “the drugs quit working.” Drugs don’t just quit working.
“We may have some resistance issues that are building, but for the most part we have really good drugs,” Thomson said. “We have really good people and the last thing that I really start to think about are vaccines and drugs when I’m thinking about managing these high-risk calves.”
The case fatality rate is the number of cattle that were treated that died divided by the total number that were treated.
“And your case fatality rate, the true case fatality rate, in my opinion, is that 10 percent of the cattle that are treated for bovine respiratory disease that are truly sick with bovine respiratory disease—10 percent of those animals will die regardless of how we treat them.”
Often times the case fatality rates bounce between 5 percent and 10 percent, but the big kicker is morbidity, Thomson said. One scenario—a producer had 1 percent death loss one year and 5 percent the following. Pulls were 10 percent and 50 percent, respectively.
“If these animals are a true case fatality rate, the case fatality rate is the same. So what was the difference between last year and this year? The number of cattle we pulled, right?” Thomson said. “The morbidity rate, and the drugs are working the same. The management is working the same. The difference is for some reason, the morbidity rates of the animals that came into the yard has changed.”
He said a few things could be causing the problems—the source of the cattle, viral antigens, weather, employees and management.
“Then you start to think about transportation and evenness of cattle, and things of that nature, the problem of morbidity is important,” Thomson said.
Overwhelming the system is a huge part of the problem with high health risk cattle. In July and August when feeding is slow and no cattle are coming in, feedyards are often looking for something to do. Then, the market happens to break.
“The market dictates when we can bring cattle in, and when we bring in too many that we can’t get processed—too many in that we can’t get into pens, and we’re commingling. That’s when we start to overwhelm the system and not have enough people,” Thomson said. “And we do this at a point in time when we don’t have enough people and we’re just going to ride through this.”
When cattle weight goes up, morbidity goes down.
“Once you get to 600-pound animal, for death loss, for morbidity rates, it pretty much starts to flatten out with those cattle,” Thomson said.
Mexican cattle will have a lower morbidity rate in a lighter weight class because of their age and some other characteristics the cattle have.
When thinking about commingling cattle, Thomson said research has shown how far the cattle came from. A barcode reader let them know where the cattle in “put together” loads originated.
“It was amazing to me when we would look at cattle that would go into sale barns, into order buyers and then come out to the cattle feeders,” he said. “On average, of put together cattle at sale barns, those cattle came from 32 different sale barns in five different states, per load. 100 head per load. Now, you talk about commingling.”
Another thing to think about, Thomson said, the average cowherd size in the U.S., is about 40 head. With 80 percent conception rate, that means about 32 calves per cow-calf operation.
“If we average 15 steers and 15 heifers per cow-calf operation we’re going to have to commingle five or six operations to fill a pen whether they go through an auction market or not,” Thomson said. “Commingling is going to happen, and it’s going to have to happen in the industry.”
Transportation also plays a role with high health risk cattle.
“It used to be eight hours was a long haul and today we say anything eight hours and in is local cattle, right?” Thomson said. “’Cause now we get cattle from all over the place. And it’s not unheard of to hear cattle coming from 24 hours away.”
Air circulation in the trailer is also important. Metal tops on the trailers can generate a lot of heat, and manufacturers are now starting to replace some of the tops with white fiberglass.
“Not only does it reflect the heat, but it lets some of the heat come off,” Thomson said. “The stress that it puts on the cattle in the top of having metal tops for 24-hour period being hauled in late August or early September is traumatic.”
Diesel exhaust and smoke also need to be considered.
“We’ve got some really neat studies coming out showing that diesel smoke that’s going back into the trailers that the cattle are inhaling,” Thomson said. “We’ve been looking at it in fat cattle as well, and the percent diesel smoke inhaled on the way to the packer.”
When trying to fill a feeding pen, it is tempting to “add on” cattle.
“Our research found for morbidity of cattle, if it takes us longer than five days to build a pen, a wreck’s coming,” Thomson said.
Another wreck could come when receiving cattle. Pens need to be dry and cattle need a place to lie down.
“What do calves want to do there when they are tired? They want to lay down,” Thomson said. “It’s something else when we have these cattle that cost $1,200 bucks coming into a yard, and we put them into—we’d love to have mud right now, so don’t get me wrong—but when those cattle are standing there shaking looking for a place to lay down.”
If workers don’t have time to clean the entire pen, Thomson suggests using a box blade to give the cattle a dry spot to lay.
“The cattle will be laying down where you give them a place to lay,” he said. “Those are just some simple things for decreasing it.”
Heat can also be a detriment to high health risk cattle.
“It’s amazing to me when it’s 97 degrees outside, the dirt floor in a feeder pen is 137 degrees,” Thomson said. “It’s extremely hot, but when we put some insulation like six inches of straw we could reduce that ground temperature by 25 degrees.”
When processing incoming cattle at the feedyard, Thomson stressed that it’s not a timed event.
“Processing is a quality event, not a quantity event,” Thomson said.
Thomson suggests feeders work with their veterinarian to determine what their needs are with regard to drugs/vaccinations and timing at processing. From a survey, he said 23 consulting veterinarians recommend an IBR and a BVD vaccine. He tries to err on the side of caution when giving other drugs. Often he will recommend the clostridial vaccination and if they haven’t gotten a black leg vaccine, it’s recommended when the cattle come into the feedyard.
“I’ve seen three black leg outbreaks in the last decade in starter yards and feed yards and it wasn’t pretty,” Thomson said. “Now the difference between high-risk cattle and low risk cattle really comes back to dropping out the bacterial vaccines at processing.”
Once the cattle are settled in the feedyard, working with the nutrition crew is important, because it’s the best predictor of a wreck coming.
“If cattle are eating a percent and half of their body weight by a week and a half, by seven to ten days on feed, a wreck is coming, and it’s just as good a predictor we’ve got,” Thomson said. “Either the wreck is simmering and it’s about to happen, or its happening or its fixing to happen. But stressed cattle don’t eat, and cattle that don’t eat get sick.”
Consultants say the best-sized pen to feed high-risk calves was a 100 head pen, with 13 inches of bunk space per head.
“My rule of thumb on bunk space is with high risk calves, we want them all to be able to get to the bunk at once,” Thomson said. “If I can fit them in a 100 head pen or smaller, one load pen, which means I’m not going to commingle too much.”
When treating the sick high health risk cattle, the hospital becomes an important part of the puzzle.
“There is no drug that will make up for hospital pen or weather,” Thomson said. “If you’re going to put shade anywhere on the feed yard, the first place I’d put it is in the hospital pen system, and the hospital pens are the most abused pens on the feed yard.”
Cattle in the hospital need as much space as one in a regular feeding pen would need. As for shade, cattle need 20 square feet of shade per head. Clean equipment should also be considered.
“We get salmonella wrecks and E. coli wrecks when you’re using drenches or probiotics and we’re not cleaning,” Thomson said. “Flies are great vectors for salmonella and E. coli. Got to make sure we clean that stuff up and we don’t get that going. And the water tanks. That should be the best water, the freshest feed anywhere is in our intensive care unit with our sick calves.”
One last thing to think about, Thomson said, when considering treating one calf or the whole pen for sickness, consider a couple of things.
“If cattle are pulled during day 0 to 14 we bought the problem. If they’re pulled 14 to 21 or whatever, start to look at maybe a nutritional glitch, and then that 28 to 35 or 28 to 40, that’s that natural break in ranch fresh calves,” he said. “When I start to see pull rates out there at 60 to 90 days, go up through the roof, I start to think about persistent infection or vaccine failure or potential, or something of that nature.”
When a pen is “going to heck” Thomson sees no point in vaccinating the cattle again—saying he wouldn’t go get another flu shot when he got sick with the flu.
“We’re setting up, trying to protect against that secondary infection—that bacterial infection—so, I’m to the point in time where I’ll either temp and treat or mass treat,” Thomson said. “The research will say either one of them will work the same.”
Kylene Scott can be reached by phone at 620-227-1804 or by email at firstname.lastname@example.org.