Evaluating the effects of feeding management practices and ruminal acidosis on the development of liver abscesses in beef × dairy crossbred steers

Authors: LOEFFLER, TAYLOR - Texas Tech University; HALES, KRISTIN - Texas Tech University; NAGARAJA, T - Kansas State University; AMACHAWADI, RAGHAVENDRA - Kansas State University; LAWRENCE, TY - West Texas A & M University; SCHWARTZ, TRENT - West Texas A & M University; PERKINS, TOMMY - West Texas A & M University; Sanchez, Nicole; THOMPSON-SMITH, AUBREY - Texas Tech University; CHILDRESS, KALLIE - Texas Tech University; DORNBACH, COLTEN - Texas Tech University; SITKA, BLAKE - Texas Tech University; GRANT, MADDIE - Texas Tech University; ABBASI, MINA - Kansas State University; SHI, XIAORONG - Kansas State University; GALYEAN, MICHAEL - Texas Tech University; Broadway, Paul

Submitted to: Applied Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Liver abscesses cost producers and the food industry about $1 billion each year. A common theory is that liver abscesses are caused by high-starch diets and acidosis. However, recent evidence suggests presence of the abscess-causing bacteria is just as important. A collaborative study with scientists from the USDA-ARS and several universities evaluated the effect of diet and bacteria on liver abscess formation. An important finding of this study is the ability to induce liver abscesses without acidosis. The presence of the bacteria that cause liver abscesses may be more important than diet or feed management. These data will be of interest to scientists studying liver abscesses and to cattle producers.

Technical Abstract: We assessed the effects of feeding management practices, ruminal acidosis, and Fusobacterium necrophorum subsp. necrophorum and Salmonella enterica serovar Lubbock inoculation on liver abscess (LA) development in beef × dairy steers. Beef × dairy steers (n = 40, initial BW = 88 ± 2.2 kg) were assigned randomly to 1 of 4 treatments: NCON = a high-starch diet representative of a standard finishing diet (STD) with no inoculation or acidotic cycles; PCON = a high-concentrate acidotic diet (AD) in which steers were cycled 3-times between AD and a low-starch diet (LS) plus 3 intraruminal inoculations of F. necrophorum and S. enterica (1 ' 106 CFU/steer ,each); STDF = a high-starch diet (STD) and 3 intraruminal inoculations of F. necrophorum; and STDFS = a high-starch diet (STD) and 3 intraruminal inoculations of F. necrophorum and S. enterica. Steer was the experimental unit. Continuous data were analyzed using mixed models, and categorical data were analyzed using binomial proportions with treatment, time, and their interaction as fixed effects. Hematology was evaluated on d -12, 0, 10, 22, and the day before harvest on d 33 to evaluate signs of systemic infection. No differences among treatments were observed for rumenitis (P = 1.00) or lung scores (P = 0.58). Prevalence of LA was 0, 22.2, 33.3, and 44.4% for NCON, PCON, STDF, and STDFS, respectively, but did not differ among treatments (P = 0.86). No correlation was observed between LA presence and other variables including feed disappearance, blood hematology, and rumen, lung, colon, or ileum scores (P > 0.22). Ultrasonography as a method to detect LA showed increased sensitivity, specificity, and accuracy as days after the intraruminal inoculation increased, suggesting the need for further research on detection strategies and techniques. An important finding of this study is the ability to induce LA through continuous feeding of a single high-concentrate diet by intraruminal inoculation F. necrophorum subsp. necrophorum and S. enterica. This experiment confirms that acidotic cycles are unnecessary to induce LA, and the presence of pathogenic bacteria in the rumen could be more influential in LA formation than diet or management practices alone.