Exploratory observational quantification of liver abscess incidence, specific to region and cattle type, and their associations to viscera value and bacterial flora

Abstract

Objective: Our objective was to quantify incidence and economic effect of liver abscesses and identify predominant bacterial species specific to severity of abscesses, geographical region, and cattle type. Materials and Methods: Observational liver audits occurred at 7 fed-beef (n = 130,845 livers) and 4 cull-beef (n = 30,646 livers) processing facilities. At each processing facility, intact liver abscess samples were collected and cultured for Fusobacterium necrophorum, Trueperella pyogenes, and Salmonella enterica. Outcome frequency and economic data were analyzed using generalized models with fixed effects of region, cattle type, or liver score. Results and Discussion: Average liver abscess incidence was 20.3% for cattle slaughtered at fed-beef processing facilities and 17.6% for cattle slaughtered at cull-beef processing facilities. Within cattle type, fed Holsteins had greater (P < 0.01) abscess incidence rates (25.0%) than fed-beef steers (18.2%) or heifers (19.1%). Cull dairy cows, cull bulls, and cull range cows had total abscess incidence rates (19.8, 19.3, and 16.7%, respectively) similar to fed steers and heifers. Fusobacterium necrophorum ssp. necrophorum was present in 79.9% of samples collected from fed-beef processors and 76.9% of samples from cull-beef processors; Salmonella enterica was present in 27.5% of abscess samples collected from fed-beef processors and 16.5% of samples from cull-beef processors. Implications and Applications: Total visceral losses ($/animal) did not differ by region (P = 0.48) or cattle type (P = 0.86), yet conservative estimates indicate that liver abscesses and other liver abnormalities cost the beef industry approximately $60 million annually in viscera losses.