Effects of oxytetracycline and copper sulphate, separately and together, in the rations of growing pigs

Abstract

1. A co-ordinated trial has been carried out at twenty-one centres to study the effects of feeding to growing pigs oxytetracycline (10 g./ton) and copper sulphate (2 lb./ton) separately and together. Fifteen centres repeated the test and thus there was a total of thirty-six pens with 245 pigs on each of the four treatments.2. Growth rate and efficiency of food conversion were significantly improved by addition to the ration of copper sulphate (9·7 and 7·9% respectively) and of oxytetracycline (3·1 and 2·3% respectively). The improvement due to copper sulphate was significantly greater than that due to oxytetracycline. There was no further improvement when both supplements were fed together.3. The cold dead weight of the pigs was significantly increased by the two supplements, the carcasses were shorter, and the streaks thicker. Supplementation with oxytetracycline resulted in slightly increased fat over the eye muscle and supplementation with copper resulted in increased depth of eye muscle. Percentage yields of fore-end, middle and gammon were not affected by either supplement.4. None of the treatment × centre interactions was significant.