Liver abscesses are nothing new to beef packers. But they have gained more widespread attention from processors and producers in recent years due to the influx of dairy-beef animals being sent through the beef supply chain. The condition is more common in these crossbreds but is rising in both native and dairy-influenced cattle.

Data from West Texas A&M University found liver abscesses in native beef cattle about 30% of the time and in dairy-beef animals 50% to 60% of the time, shared the university’s Kendall Samuelson. The associate professor of feedlot nutrition and management explained during an Oklahoma State University Extension beef-on-dairy webinar that abscesses are scored based on three levels of severity: A-, A, and A+. Those most damaging A+ abscesses may also be adhered to the diaphragm or even ruptured.

Depending on the severity and case, a liver abscess can lead to losses of valuable skirt steak and other surrounding meat. Discarding that product can cost a packer anywhere from $4 to $239 per head, according to a 2024 study described by Samuelson.

How they may develop

In addition to the lost revenue from that animal and potential challenges with a processor, beef producers should be concerned with liver abscesses because they can lead to reduced average daily gain and efficiency. So, what can be done to reduce the number of liver abscesses?

Samuelson explained that there is not one clear cause of liver abscesses, but it is widely accepted that they are more common in animals that experience ruminal acidosis.

A general definition for acidosis is when the rumen pH drops below 5.8, she began. Feedlot cattle typically experience fluctuations in rumen pH throughout the day, but when that low pH persists for a long period of time due to volatile fatty acid accumulation, the ruminal wall and microbial population of papillae can be affected. “Once [that damage] occurs, if it is severe enough to essentially burn off the papillae with that low pH environment, that papillae never grows back,” said Samuelson.

Then, lesions and consolidation will occur. “This essentially provides a window out of the side of the rumen for the bacteria that are in the rumen to escape,” Samuelson continued. Some of those bacteria can then colonize on the liver, causing the organ to attempt to wall off the infection. This creates the abscess. Samuelson noted Fusobacterium necrophorum is one pathogen of concern that has been cultured from many liver abscesses.

Anything that affects an animal’s starch intake will lead to higher acid production in the rumen. Samuelson’s group conducted a study on four groups of feedlot yearlings to see if abscesses would be induced by higher starch diets and variable feeding management. Altered eating behavior can lead to changes in starch intake, she noted.

Half of the animals received a standard finishing diet with 49.1% starch, while the others received a diet with 64.4% starch. Within each treatment, half of the animals were fed consistently, and the other half were randomly overfed, underfed, and/or received feed up to four hours later than usual.

Surprisingly, there was no statistical difference in the proportion of animals with a liver abscess between those fed regularly and those on the erratic feeding schedule. But there was a significant difference between the two diets. One-third of the animals on the standard diet developed an abscess, but 55% of the cattle on the high-starch diet had a liver abscess. This supports the theory that abscesses are related to acidosis, Samuelson stated.

However, she cautioned that the health of the rumen may not be the only factor related to abscesses. In another study, they saw groups of animals with high rates of liver abscesses but lower rates of papillae damage as well as animals with serious rumen damage but fewer abscesses.

It’s more than likely that there’s still much we don’t know about liver abscesses, Samuelson admitted. Still, she recommended that feedlot producers take steps to limit acidosis and animal stress. Medicated feed additives are the primary tool available to combat abscesses, she added.