Watch for signs of acidosis

MANHATTAN, Kan. — It is not known if cattle feel pain when they suffer from liver abscesses or acidosis, but they do show symptoms that something is wrong, says veterinarian Kelly Lechtenberg.

There is physiological evidence of pain when an animal is suffering from acidosis, but there are fewer signs unless abscesses are severe.

Sometimes those symptoms are mistaken for respiratory disease, but the same treatment works for rumen upsets, he said at the International Beef Welfare Symposium, which was held in Manhattan, Kansas earlier this summer.

“If we see them clinically, we treat them for something different,” he said. “We suspect they are BRD, and usually they are associated with the acidosis thing going on.”

Liver abscess rates have been increasing, which is connected to cattle welfare, he said.

North American beef production tends to rely on fermentable feed, which leads to the production of volatile fatty acids. Rumen microbes are used to digest forage, and problems can occur when animals eat a high grain diet for an extended period of time.

Acid production is always happening, but it is absorbed and used under normal conditions. Rumen bacteria may be killed when levels are too high.

“The more fermentable the acids are, the more we increase the likelihood of acid production at a rate higher than the calf, or the protozoa in the rumen can utilize them,” he said. “We hit some tipping points on when utilization fails to meet production, and the microbial changes that cause that to happen get out of control.”

Acidosis risk increases this time of year as the weather heats up and humidity increases. It is especially common in black hided cattle that are close to slaughter weight.

Loose stools are seen, and fermentation continues in the feces so that they look watery and bubbly.

Calves do not feel well and breathe rapidly to blow off excess carbon dioxide.

“We may not recognize it for what it is. We think it is BRD and give them a shot of antibiotic and change their diet,” he said.

“It is doing the right thing for the wrong reason for these calves.”

Stable rumen pH is around 5.6, but calves go off feed, become lethargic, grind their teeth, become dehydrated, get diarrhea and appear depressed because of acute acidosis once it dips below five or four.

Liver abscesses are associated with episodes of rumen acidosis, which are usually caused by carbohydrate overload.

Rumen acidosis damages the rumen wall and allows bacteria to pass into the bloodstream and enter the liver, where they can cause abscesses to form.

The duct between the rumen and the liver is about five centimetres long, making it a quick route to carry bacteria from one organ to the next.

“If all is not well in the rumen, that important trip can carry with it a large bacterial load,” he said.

Ninety-five percent of the microbes in the gastrointestinal tract are bacteria, and the others are protozoa. The role of the protozoa is less important as grain is increased in the diet.

Abscesses are increasing faster in dairy cattle than beef cattle. As well, some feedlots may have no problems, while others have an incidence of 20 percent, which Lechtenberg attributes to different management styles.

Cattle can receive products such as tylosin to control the problem, but alternative approaches may be needed as the trend to cut back on antibiotics continues.

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