The prevalence and economic significance of liver disorders and contamination in grain-fed and grass-fed cattle.

Livers were examined from 5,647 grain-fed and 621 grass-fed cattle of similar breed, age and weight, killed at a Queensland abattoir in 1980-81. The prevalences of disorders found in grain-fed cattle were liver abscesses 5.6% and 11.1% (after 80 and 120 days in the feedlot), telangiectasis 8.4%, Echinococcus granulosis 3.3%, Fasciola hepatica 0.4%, unclassified lesions 7.4%, and contamination 3.2%. In grass-fed cattle liver abscesses were 0.2%, telangiectasis 1.0%, E. granulosis 18.9%, F. hepatica 5.4%, unclassified lesions 6.5%, and contamination 1.0%. Liver abscess disease was the main cause of loss in grain-fed cattle and the mean carcase weight of affected steers was 298kg +/- 42kg, compared with 308kg +/- 40kg in non-affected (p less than 0.01). Liver weights of grain-fed and grass-fed cattle were highly significantly correlated with carcase weights (r = 0.78 and 0.49 respectively). Total losses were $2.25 per head in grain-fed steers and $0.90 in grass-fed steers.