Supplementation of bacon pig rations by aureomycin and two levels of copper sulphate

Abstract

A trial has been carried out to determine the effects of supplementing bacon pig diets with 125 and 250 ppm. copper (as copper sulphate) and/or aureomycin (14·4 ppm.). A total of 288 pigs were fed ad lib. from 40·100lb., and restricted-fed thereafter to bacon weight (200 1b.). Growth rate was increased by 125 ppm. copper, 250 ppm. copper, and aureomycin during the ad lib. feeding period. The magnitude of the responses was about the same in each case.During the fattening stage from 100 1b. to bacon weight, 125 ppm. copper or aureomycin increased food conversion efficiency; 250 ppm. copper however improved growth rate also. There was probably some additive effect of 125 ppm. copper and aureomycin when fed together, but it is unlikely that such an effect occurred with the higher level of copper and aureomycin.The liver copper content of pigs fed 125 ppm. copper was 3 times higher than that of the controls; 250 ppm. copper increased liver copper storage about 18·fold.The similarity in response of copper and aureomycin feeding to pigs is discussed. It is concluded that, under the conditions of the trial, their mode of action is similar. Under similar conditions in general farm practice there is unlikely to be any economic advantage in supplementing pig diets containing 250 ppm copper with aureomycin; however, the bacterial environment may sometimes be such that additional benefit will be obtained by joint supplementation.