As beef-on-dairy cattle become a larger part of the U.S. fed cattle population, research is ongoing to better understand the health challenges that may accompany these animals through the production system. One issue receiving increased attention is liver abscesses, a condition associated with reduced performance, carcass losses and significant economic costs.
It is now believed the true impact of liver abscesses may begin long before harvest. During a recent Beef on Dairy Dialogue webinar, Kendall Swanson, professor of beef production systems at North Dakota State University, discussed emerging evidence on how liver abscesses may increase maintenance requirements and reduce growth efficiency throughout the feeding period, raising new questions about when abscesses develop and how they affect beef-on-dairy performance.
Traditionally, liver abscesses have been measured at harvest, where condemned livers and carcass trimming provide visible evidence of their economic impact. Swanson suggests those losses may represent only part of the story. By increasing maintenance requirements and redirecting energy toward inflammation and tissue repair, liver abscesses may reduce performance throughout the feeding period.
The Hidden Cost of Liver Abscesses on Feed Efficiency
Every calorie consumed by a feedlot animal has a destination. It can be used to maintain existing tissues and biological functions, or it can be directed toward production, including growth. Maintenance includes everything from nutrient metabolism and protein turnover to immune responses and tissue repair. The more energy an animal must devote to maintenance, the less remains available for gain.
“If we could shift that more toward production and less toward maintenance, we could improve energetic efficiency,” Swanson says.
That concept sits at the center of the liver abscess discussion. When abscesses form, cattle must devote energy to inflammation, immune responses and tissue repair rather than growth.
“It takes energy to deal with that abscess tissue. Cattle have to use more energy for maintenance and have less to use for production,” Swanson explains.
Why Beef-on-Dairy Cattle Face Unique Liver Health Challenges
The beef-on-dairy sector has expanded rapidly in recent years, driven by widespread adoption of sexed semen and beef sire programs within the dairy industry. These cattle bring many advantages to the feedlot, including strong feed intake and growth potential.
“Dairy cattle are bred to eat, and they’re great at that,” Swanson says.
That appetite helps drive performance, but it may also increase the importance of digestive health management.
In a recent Kansas State University study, liver abscess prevalence ranged from 7.6% to more than 20% among over 500 beef-on-dairy steers fed different growing-phase diets, with the lowest prevalence observed in cattle managed on a moderate-energy, limit-fed program. The results suggest management decisions made months before finishing may influence liver health and subsequent performance.
Unlike many native beef calves, beef-on-dairy cattle often begin consuming grain-based diets as young calves and may move through several production systems before reaching the feedlot. Each transition can create stress and disruptions in feed intake that may contribute to liver abscess risk.
Evidence That Liver Abscesses May Begin Earlier in Life
Historically, liver abscesses have been associated with high-grain finishing diets and ruminal acidosis. The traditional theory suggests acidic conditions damage the rumen wall, allowing bacteria to enter the bloodstream and travel to the liver, where abscesses form.
Recent research suggests the story may be more complicated.
A collaborative study involving researchers from Texas Tech University, Kansas State University and USDA successfully induced liver abscesses in young beef-on-dairy steers through intraruminal inoculation with Fusobacterium necrophorum and Salmonella enterica. They concluded ruminal acidosis was not required for liver abscess formation and the presence of the causative bacteria alone was sufficient to induce abscesses. The calves in this study weighed only about 194 lb. at the start of the experiment, suggesting liver abscess development may begin much earlier than many producers assume.
The study raises new questions about when liver abscesses begin and what factors contribute to their development long before harvest.
Potential risk periods include:
- Weaning
- Transportation
- Commingling
- Diet transitions
- Fluctuations in feed intake
- Other periods of physiological stress
Major challenges still exist because liver abscesses are difficult to identify before harvest. In many cases, cattle appear healthy and abscesses are only identified at slaughter.
Ultrasonography may offer a useful diagnostic tool. In the Texas Tech-Kansas State study, ultrasound accuracy to detect abscesses approached 97% near the end of the trial, raising the possibility that researchers may eventually be able to monitor liver abscess development before cattle reach harvest.
How Liver Abscesses Redirect Energy Away From Growth
“The liver really is central to coordinating nutrients and other things that get to the whole body for growth or milk production,” Swanson says.
Although the liver represents a small percentage of body weight, it is one of the body’s most metabolically active organs.
“The gastrointestinal tract and liver may be 20% to 25% of total body weight, but if we add the liver, heart, lung and pancreas, we get close to 50% of total energy use,” Swanson says.
As a result, even relatively small changes in liver health can have outsized consequences for performance.
According to Swanson, liver abscesses may influence performance in several important ways:
- Liver abscesses increase maintenance requirements.
- Inflammation and tissue repair consume energy that could otherwise support growth.
- Enlarged or damaged livers require additional energy to maintain.
- Growth efficiency declines as more nutrients are diverted toward maintenance.
- Performance losses may occur long before abscesses are discovered at harvest.
Swanson estimates increasing liver mass from 1.25% to 1.5% of body weight could increase maintenance requirements by around 4%, potentially reducing average daily gain by 0.25 lb. per day.
“Why is growth efficiency decreased in cattle with liver abscesses?” Swanson asks. “ I think really a large part of that increased energy requirement is the abscess portion.”
Those losses may help explain why liver abscesses carry costs beyond condemned organs and carcass trim.
Management Strategies to Help Reduce Liver Abscess Risk
While research continues to investigate exactly when liver abscesses develop and how they affect performance, several practical themes are emerging.
Rather than viewing liver abscesses solely as a finishing-yard issue, veterinarians may need to approach them as a whole-life management challenge.
Key areas of focus include:
- Reducing stress during transitions
- Maintaining consistent feed intake patterns
- Managing diet changes carefully
- Supporting rumen health during growing and finishing phases
- Evaluating feeding strategies that include adequate roughage and coproducts
- Monitoring calf health and nutrition long before cattle reach the feedlot
Swanson believes it is important to avoid searching for a single explanation.
“I think it’s really nutrition, health, stress, all those things combined, and they kind of compound on each other,” he says.
As researchers continue to investigate when liver abscesses develop and how they affect growth, veterinarians may need to view them not simply as a harvest-day finding, but as a whole-life health challenge that influences performance from calfhood through finishing.
