The effect of trenbolone on acetate growth, blood hormones and metabolites, and nitrogen balance of beef heifers

Abstract

Four animals from a group of eight Hereford × Friesian heifers weighing approximately 365 kg were implanted with 300 mg trenbolone acetate at the beginning of a 60-day trial period. Treated heifers grew more quickly (P<0·05) and converted food to liveweight gain more efficiently (P < 0·01) than untreated cdntrols. They had lower overall concentrations for serum albumin and plasma urea (P<0·01), the differences being maintained throughout the diurnal periods studied. No significant differences were recorded in the mean values for serum total protein, plasma glucose or free fatty acids. Similarly, the absence of significant differences in the mean values for serum growth hormone, insulin and prolactin suggested that these hormones did not mediate the response to trenbolone acetate. Implanted heifers had a significantly greater retention of nitrogen (P<0·01) which was mainly due to a reduction in the excretory products associated with total urinary nitrogen.