Infertile bulls versus steers: II. Feed conversion efficiency and the effects of a high fat diet

Abstract

SummaryThe feed conversion efficiency of four intensively fed, partially castrated male cattle, measured over an 11-week period from approximately 9-months of age, was found to be significantly higher (P <0·05) than that of four steers.The effect of adding 5% beef tallow to the diet during this period was also studied. Although no statistically significant result of this on feed conversion was obtained, there was an indication that fat in the diet improved the bulls' efficiency, but not that of the steers. Added dietary fat had an effect on carcass composition, increasing signifioantly (P < 0·05) the deposition of carcass fat by steers but having no such effect in bulls. It appears, therefore, that the two sex types metabolized the added dietary fat differently, the steers converting much of it to depot fat; the bulls using it (with some evidenoe of greater efficiency) for growth of non-adipose carcass components.