Scientists research the cause and development of liver abscesses in cattle

It is imperative to study the bacteria responsible for liver abscesses in cattle to prevent the condition effectively.

Scientists from the U.S. Department of Agriculture (USDA) Agricultural Research Service (ARS), Texas Tech University, Kansas State University and West Texas A&M University collaborated on liver abscess models to identify what triggers this costly condition in cattle.

Liver abscesses negatively impact the animal’s well-being and cause liver condemnations, leading to increased carcass trimming and an overall decrease in profitability.

The first successful study on liver abscesses in cattle was recently published on March 6 in the Journal of Animal Science.

The study was part of a series conducted at the USDA ARS Livestock Issues Research Unit in Lubbock, Texas, focusing on finding a solution to an issue costing the industry millions of dollars.

The mission of the unit is to conduct research to determine and develop management practices and alternative production systems which reduce animal pathogen loads prior to processing and to enhance animal well-being.

Research objective

According to the study, cattle with liver abscesses may experience health problems, reduced growth and feed efficiency, but they don’t always show clinical signs.

Economic losses associated with this condition in cattle have been reported to reach $400 million annually.

“After decades of studies, researchers haven’t found an accurate way to predict nor diagnose liver abscesses because of the complexity of the disease,” says Rand Broadway, a research scientist with the Livestock Issues Research Unit. 

“Our study is a huge collaborative effort between USDA and academic partners to develop a liver abscess model in cattle to help us better understand how liver abscess formation begins. We are constantly learning about the causes and development of these abscesses,” he adds. 

USDA ARS states it is important for researchers to study liver abscess development and prevention strategies, particularly in calves entering the beef supply chain from dairy origin. 

During the study, the scientists mimicked “real-world” disease etiology while examining the animal’s physiological changes to better understand the disease’s root cause.

“We are trying to ensure this study is effective and applicable to test non-antibiotic interventions in the future,” adds Broadway. “We seek to use the knowledge gained from these models to develop different alternative interventions, such as nutrition management strategies.”

The study focused on cattle which commonly suffer from this infection, including dairy and beef-dairy cross steers. 

During the study, researchers tested two diet types – a high-grain and forage-based diet – and three common bacteria found in liver abscesses – Fusobacterium, Trueperella and Salmonella.

The results from the high-grain diet model were found to be more reliable, leading scientists to focus more on this model.

Impact of diet

Liver abscesses in cattle are generally thought to occur with a high-energy diet. The theory is when cattle are fed elevated levels of grain, highly-fermentable starch in the rumen is rapidly fermented by bacteria, causing a drop in rumen potential hydrogen (pH). 

This acidity pH causes damage to the rumen lining, allowing bacteria to travel into the blood, reaching the liver and other organs where they can cause infection. 

However, it is still unknown, with accuracy, the exact route these bacteria take to cause infection or injury to the liver, states USDA ARS.

Scientists discovered the bacteria associated with liver abscesses in cattle may not always originate from the rumen, it may travel from the lower gastrointestinal tract. 

The research showed in some cases, when these bacteria were not detected in the acidic rumen environment caused by a high-grain diet, no liver abscesses were detected. But, when bacteria were directly introduced to the rumen, they observed the formation of liver abscesses and were able to isolate the bacteria from the infected sites.

The research study confirmed an acidotic diet, combined with bacterial inoculation in the rumen, can be used as a model to induce liver abscesses. 

The research team recommended further research should be conducted to determine the study’s consistency before it can be used to evaluate new interventions to prevent this complex infection.

Currently, the primary treatment to prevent liver abscesses in cattle has been in feed antibiotics, but alternatives to antibiotics are being sought.

Melissa Anderson is the editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.