Evaluating bacterial inoculation and dietary changes to study the genesis and prevalence of liver abscesses in cattle

Authors: MCDANIEL, ZACHARY - Texas Tech University; HALES, KRISTIN - Texas Tech University; NAGARAJA, T - Kansas State University; LAWRENCE, TY - West Texas A & M University; TENNANT, TRAVIS - West Texas A & M University; AMACHAWADI, RAGHAVENDRA - Kansas State University; Carroll, Jeffery - Jeff Carroll; Sanchez, Nicole; GALYEAN, MICHAEL - Texas Tech University; BALLOU, MICHAEL - Texas Tech University; MACHADO, VINICIUS - Texas Tech University; Broadway, Paul

Submitted to: Proceeding of Plains Nutrition Council Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 2/22/2023
Publication Date: 9/1/2023
Citation: McDaniel, Z.S., Hales, K.E., Nagaraja, T.G., Lawrence, T.E., Tennant, T.C., Amachawadi, R.G., Carroll, J.A., Sanchez, N.C., Galyean, M.L., Ballou, M.A., Machado, V.S., Broadway, P.R. 2023. Evaluating bacterial inoculation and dietary changes to study the genesis and prevalence of liver abscesses in cattle. Proceeding of Plains Nutrition Council Symposium. p. 112.

Interpretive Summary:

Technical Abstract: Our objectives were to study the genesis of liver abscesses (LA) using an acidotic diet and oral bacterial inoculation (phase I) and a 3 x 2 factorial arrangement of treatments to evaluate the effects of dietary neutral detergent fiber (NDF) concentrations from alfalfa hay of 3, 4.5, or 6% and 24 or 32 lb/bu of steam-flaked corn (SFC; 33 or 69% starch availability, respectively; phase II) in finishing beef steers. In phase I, Holstein steers (187 ± 15.6 lb) were assigned to either a negative control diet (CON; n = 13), an acidotic diet (AD; n = 13), or an acidotic diet plus intraruminal inoculation with a bacterial mixture (ADB; n = 14). Steers in AD and ADB were cycled on (3 d) and off (2 d) a high-starch diet for 20 d before inoculation with Fusobacterium necrophorum, Salmonella Lubbock, and Truperella pyogenes. Boluses were inserted to monitor ruminal pH throughout the study. Twenty days after inoculation, steers were euthanized and subjected to gross necropsy. During phase II, finishing beef steers (n = 214; 60 pens; 10 pens/treatment; initial BW 919 ± 26.2 lb) were randomly assigned to treatments and fed an average of 112 d. For phase I, 43% of calves in ADB had culturable LA, whereas no LA were present in CON or AD (P < 0.01). The F. necrophorum cultured from LA was phylogenetically typed and identical to the strain in the bacterial inoculation. Ruminal damage was 51% greater in ADB than CON or AD (P < 0.01). There was a treatment × time interaction for ruminal pH, in which pH decreased in AD and ADB calves during each cycle of acidotic diet (P < 0.01). In phase II, no interactions between roughage NDF and bulk density of SFC were observed (P > 0.18). Presence of LA at harvest was less (P = 0.05) in the 4.5 and 6% roughage NDF and 32 lb/bu SFC treatments. No differences were noted in growth performance throughout the study (P = 0.28). Marbling score was greater in steers fed 3% (P = 0.05) than 4.5 or 6% roughage NDF, and steers fed 24 lb/bu SFC tended to have a larger longissimus muscle area (P = 0.10). No other carcass differences were observed (P = 0.40). Results from phase I indicate that acidotic diet cycles in conjunction with an intraruminal bacterial inoculation can result in formation of LA, thereby providing a potential model to study the etiology and prevention of abscesses. Results from phase II suggest that increasing roughage NDF and bulk density of SFC decreased liver abscesses at harvest in finishing beef steers.