Liver abscesses occur in approximately 5 to 20 percent of cattle. Although the problem is typically not a large concern for feedlot managers, large numbers of liver abscesses usually draw a complaint from the packer, and might discount or pass on future cattle.
Traditionally, liver abscesses are controlled by feeding a therapeutic dose of Tylan in the ration. However, with increasing concerns of feeding antibiotics -- which has been discontinued in the European Union -- yard managers, nutritionists and veterinarians are taking a closer look at liver abscesses, what they cost the industry, their cause, and other ways to control the problem.
At the Western Veterinary Conference in Las Vegas, Nevada, five industry experts sat down at a roundtable discussion sponsored by ImmTech to evaluate the future of controlling liver abscesses in the beef industry. The discussion of Dallas Horton, D.V.M, Louis Perino, D.V.M., Ph.D., Scott MacGregor, D.V.M., James Cullor, D.V.M., and T.G. Nagaraja, Ph.D., follows.
Question: Are liver abscesses -- especially severe A+ liver abscesses -- costing beef producers/feedlot owners?
Dr. Hall: The A+ abscesses, the larger abscesses, do affect the bottom line. You're going to lose the liver. If that abscess ruptures during the process of evisceration, you're going to lose the heart, paunch, spleen, small intestine, lungs and other marketable parts. Right now I'd estimate about 10 to 12 percent of the abscesses that come through are open abscesses, which equals about $14 per head, possibly as much as $20 per head.
When you start to figure in your impact on cost of management, it isn't costing feeders anything -- right now. But it's definitely costing the packer. If he can figure a way to pass that cost on to the feedlot or owner, he will.
Dr. Perino: Liver abscesses are usually not the number-one issue on the feedyard manager's mind until he receives a packer complaint. As long as the percent and severity remain within a range that everyone is used to dealing with, it's not an issue. However, the biggest challenge facing cattlemen is how to reduce liver abscess prevalence and still optimize the performance parameters that we currently benchmark. Given our current state of knowledge, I'm not sure we can reduce liver abscesses without losing ground on traditional performance indicators.
Dr. Hall: I know for a fact that packers would like to screen and then discount cattle, or just not buy them, if you have a high incidence of liver abscesses. I believe the incidence of abscesses are reflected in the price of cattle now. According to Dr. Perino, our industry accepts up to 15 percent liver abscessation. The price of cattle is discounted for a 15 percent liver abscess incidence. If you were able to guarantee that your cattle were only going to have one to two percent liver abscessation, you could request from the packer (and probably receive) a premium for your cattle.
Q: Should we be concerned about the reliance on antibiotics in the feed to control liver abscesses?
Dr. Nagaraja: As an industry, we should be concerned. Particularly, as Europe is clamping down on using feed-grade antibiotics. I don't know when it's coming to this country. But I have a feeling, eventually, we may have to live without antibiotics as feed additives. I don't know how many more years we'll be able to use tylosin.
Dr. Cullor: From a national perspective, the Center for Disease Control (CDC), Food and Drug Administration (FDA) and the USDA jointly said that all antibiotic resistance in salmonellosis in humans was due to antibiotics being fed in agriculture. That's a pretty bold statement. Those of us in animal agriculture are going to have to deal with that perception. We need to plan now for what we can do should they eventually try to ban feed-grade antibiotics.
Q: Without the use of Tylan, what other choices do we have to control liver abscesses?
Dr. Cullor: Well, it's management. I'd like to see bunk management, better nutrition and immunization or vaccines. There probably won't be a single silver bullet, but a combination of how to manage for it when the antibiotics are gone. That's going to be better rations, better nutrition and immunizations.
Dr. MacGregor: Prevention is the name of the game. I think we need to look at time of prevention with the ranch being the optimum. Convince the rancher either through common sense or his pocketbook that it's worthwhile for them.
Q: Dr. MacGregor, you've had first-hand experience with a abscess vaccine. Have you experienced any duration of immunity that would indicate vaccine timing advantages?
Dr. MacGregor: Using the double vaccine strategy -- day 1 and day 40-60 at re-implant -- we have seen a reduction of overall liver abscesses and a shift from severe A+ abscesses to A-. That's been repeated in all of our studies.
Q: Do current feedlot management practices help in the alleviation of liver abscesses? What else can be done?
Dr. Perino: The intervention strategy that we use, Tylan, reduces liver abscesses. However, in the same yard, where cattle are eating the same ingredients and have similar bunk management, we see a tremendous amount of variability in the percentage of cattle with liver abscesses. That leads me to conclude that there are risk factors that affect liver abscess prevalence that we don't understand.
Q: What message do we need to send to beef producers and feedlot owners?
Dr. Nagaraja: They should know there is a concern about antibiotic resistance and we don't know how long we can use these antibiotics in animal feeds. We need to start directing them to management practices that don't lean on feeding antibiotics.
Dr. MacGregor: My immediate customer is my feedyard, but in reality our big customers are consumers. And their perception is we've got too many antibiotics in our products and maybe we are too therapy oriented. Does it make good medical sense to prevent a problem rather than to treat it? To me, it does.
Dr. Perino: If you're going to take a biological control strategy, you have to provide the protection before the challenge occurs. This means you've got to be vaccinating before you're challenging the cattle with diet changes and high-energy diets.
Q: Foot rot is caused by the same bacteria, Fusobacterium necrophorum, that brings about liver abscesses. Do you know what foot rot is costing producers?
Dr. Horton: The immediate cost is labor, and more importantly, the aggravation. It's hard for cowboys to find these problem cattle in large pastures. If you can't find them, you can't treat them. Then it becomes a clubfoot. This quickly can lead to septicemia and then the animal is condemned.
Now that there is a vaccine that could control my foot rot problems as well as control liver abscesses, I think it needs to be looked at. Foot rot can't be managed through the ration. But biological control for both foot rot and liver abscesses at the ranch level makes sense.
All information is copywrited by Feed Lot magazine and cannot be printed or re-printed without the publishers express consent. Please contact Feed Lot Magazine for reprint and copy authorization.