The use of hexoestrol for beef production from zebu cattle under ranch conditions in Tanganyika

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Abstract
1. Three groups of twenty, 3½ to 4-year-old zebu steers, replicated four times in each quarter of the year, were used to examine the effects of 30 and 45 mg. hexoestrol implants on their beef production, under ranch conditions in Tanganyika.2. Significant advantages in mean live-weight gains of 20·8–47·3 lb. for 30 mg., and 9·8–47·3 lb. for 45 mg., were obtained when treated at any time of the year; but during the dry-season implantation is contra-indicated as initial response is adverse although followed by pronounced recovery when pasture conditions improve.3. There was no significant difference between dosage rates in growth response, but on smaller steers, and as the pasture deteriorated, 45 mg. showed signs of being excessive.4. Duration of significant response was about 3 months during the period of adequate grazing, but was delayed to 5 months, and probably longer, during the dry season.5. Steers were slaughtered 6–9 months after implantation and at that time showed: no significant difference in dressing percentage, shrinkage in store, proportion of bone, or carcass grade; there was significantly less fat, and more lean, but increased proportion of moisture in the muscle accounted for the extra proportion of lean in the sample joints.Treated carcasses were significantly longer by 1·0% and highly significantly larger in circumference of hind quarter by 2·0%.