Managing ruminal bacteria may rival diet in preventing liver abscesses in beef cattle
Findings from a new Applied Animal Science study suggest that ruminal bacteria contribute to liver abscess formation even when cattle are not subjected to acidotic feeding conditions
Champaign, IL, February 2, 2026—Liver abscesses are a persistent concern in the beef industry, affecting animal welfare and contributing to substantial economic losses through reduced feed efficiency, weight gain, and, ultimately, carcass value. Following a special issue on the topic, a new study published in Applied Animal Science provides fresh insight into how liver abscesses can develop in feedlot cattle, challenging long-held assumptions about the central role of high-starch diets and ruminal acidosis. Researchers found that liver abscesses could be induced in beef × dairy crossbred steers fed a standard finishing diet when specific bacteria were introduced directly into the rumen, even in the absence of severe acidotic conditions.
The study’s lead investigator, Paul R. Broadway, PhD, of the US Department of Agriculture’s Agriculture Research Service Livestock Issues Research Unit in Lubbock, Texas, USA, explains, “Traditionally, the condition has been closely linked to high-grain diets that lower rumen pH, damage the ruminal lining, and allow pathogens to enter the bloodstream and reach the liver, where abscesses then form.” Broadway and his research team had conducted previous research that asked them to reconsider the theory that acidosis is required for abscess formation.
In their follow-on study, some animals were subjected to diet cycling designed to induce ruminal acidosis, whereas others were fed a consistent high-concentrate finishing diet matching a standard finishing diet. Select groups were inoculated with Fusobacterium, a bacterium long associated with liver abscesses, either alone or in combination with Salmonella. Liver abscesses were observed in steers fed a standard finishing diet following bacterial inoculation, supporting the conclusion that severe ruminal acidosis was not required for abscess formation.
“This study adds to a growing body of evidence showing that liver abscess development is not solely dependent on diet-induced acidosis,” said Broadway. “Our results demonstrate that introducing key bacteria into the rumen was sufficient to induce liver abscesses, even when cattle were fed a conventional high-concentrate finishing ration.”
Caption: A new study published in Applied Animal Science suggests that liver
abscesses can form without acidosis and that ruminal bacteria may play a more
influential role than diet or management alone (Credit: Taylor Loeffler).
The researchers also evaluated ultrasonography as a tool for detecting liver abscesses before slaughter. The accuracy of ultrasound improved as more time passed after bacterial inoculation, suggesting potential for earlier, noninvasive detection in lightweight feeder cattle. However, the authors caution that additional work is needed to better understand how abscess development timing and location affect detectability, particularly in heavier, finished cattle.
Bill Weiss, PhD, PAS, Dipl. ACAS, editor in chief of Applied Animal Science, emphasized the broader implications of the study’s findings. “Liver abscesses can be a substantial economic problem and an animal welfare issue in feedlot cattle,” Weiss said. “Liver abscesses are often associated with feeding high-starch diets, but this article showed that ruminal inoculation with a specific bacteria can cause abscesses with low-starch diets. Reducing the presence of this bacteria may be as, or more, important than diet or management in preventing liver abscesses.”
Broadway noted that the work supports a shift toward more integrated prevention strategies. “Nutrition and management remain important, but our data suggest we also need to pay close attention to the microbial environment in the rumen,” he said. “Understanding how and when these bacteria contribute to liver abscess formation will be key to developing more effective prevention approaches.”
The authors stress that further research is needed to clarify how bacterial populations interact with diet, ruminal health, and time to influence liver abscess development. Together, these findings contribute to a more nuanced understanding of a costly and complex condition facing the beef industry.
The article appears in the February issue of Applied Animal Science.
Notes for editors
“Evaluating the effects of feeding management practices and ruminal acidosis on the development of liver abscesses in beef × dairy crossbred steers,” by Taylor A. Loeffler, Kristin E. Hales, Tiruvoor. G. Nagaraja, Raghavendra G. Amachawadi, Ty E. Lawrence, Trent E. Schwartz, Tommy Perkins, Nicole C. Burdick Sanchez, Aubrey C. Thompson-Smith, Kallie D. Childress, Colten W. Dornbach, Blake J. Sitka, Maddie S. Grant, Mina Abbasi, Xiaorong Shi, Leigh Ann George, Michael L. Galyean, and Paul R. Broadway (https://doi.org/10.15232/aas.2025-02708), Applied Animal Science, volume 42, issue 1 (February 2026), published by FASS and Elsevier.
This article is openly available at https://doi.org/10.15232/aas.2025-02708.
To schedule an interview with the author(s), please contact Paul R. Broadway at rand.broadway@usda.gov.
About Applied Animal Science
Applied Animal Science (AAS) is a gold open access, peer-reviewed scientific journal and the official publication of the American Registry of Professional Animal Scientists (ARPAS). In continuous publication since 1985, AAS is a leading outlet for animal science research and is indexed by Scopus and ESCI (Clarivate’s Emerging Sources Citation Index). The journal welcomes novel manuscripts on applied technology, reviews on the use or application of research-based information on animal agriculture, commentaries on contemporary issues, short communications, and technical notes. Topics that will be considered for publication include (but are not limited to) feed science, farm animal management and production, dairy science, meat science, animal nutrition, reproduction, animal physiology and behavior, disease control and prevention, microbiology, agricultural economics, and environmental issues related to agriculture. Themed special issues also will be considered for publication. www.appliedanimalscience.org
About the American Registry of Professional Animal Scientists (ARPAS)
The American Registry of Professional Animal Scientists (ARPAS) is the organization that provides certification of animal scientists through examination, continuing education, and commitment to a code of ethics. Continual improvement of individual members is catalyzed through publications (including the AAS journal) and by providing information on educational opportunities. ARPAS is affiliated with five professional societies: American Dairy Science Association, American Meat Science Association, American Society of Animal Science, Equine Science Society, and Poultry Science Association. www.arpas.org
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