Effect of Anabolic Agents on Performance of Calves

Abstract

Ten feeding experiments with 563 Friesian bull calves were carried out over the growing period from 40 to 170 kg live weight, to compare the anabolic effect of a number of anabolic agents on weight gain, feed conversion and carcass quality at different times and levels of administration. The animals were housed individually in boxes in a controlled environment. They were fed a liquid milk replacer diet. The effect on weight gain was influenced relatively little when the dose of DES applied was increased from 25 mg to 2 × 100 milligrams. The time of administration was of decisive importance for the effect obtained by the injection of DES. DES administered at 5 weeks of age led to an average maximum growth-increase of 1.6 kg at about 5 weeks after treatment. Thereafter a decrease in growth as compared to the control was seen, leading to an average negative difference with the control animals at slaughter of 6.4 kilograms