Published online by Cambridge University Press: 27 March 2009
Experiments were carried out in 1992 with ten male calves, 4 weeks old initially, on a milk diet. Five calves received 80 mg/head virginiamycin (a feed antibiotic) daily for about 14 weeks. Virginiamycin significantly (P < 0·05) increased weight gains (122±2 kg ν. 114±2 kg), digestibility of ash, serum iron and haemoglobin. The feed intake per 1 kg of gain was non-significantly lowered in the virginiamycin group. The phagocytic activity of granulocytes in blood samples of treated calves was slightly increased with a concomitant decrease in the concentration of immunoglobulins. Meat of virginiamycin-fed calves tended to be somewhat darker, to contain more K, Na and Fe and to have a higher pH 24 h post mortem. There were no major differences in other qualitative characteristics of meat between the groups.