Reduction of energy requirements of steers fed on low-quality-roughage diets using trenbolone acetate.

1. Six steers implanted with 300 mg trenbolone acetate and six steers not implanted were fed on low protein, low-quality-roughage diets ad lib. in two experiments. The steers were Hereford (Bos taurus) x Brahman (Bos indicus) crossbreds (50:50), initially of about 400 kg mean live weight (LW). In the first experiment of 8 weeks duration roughage was given alone. In the second experiment of 6 weeks duration the diet was supplemented with 100 g urea and 4.6 g sulphur daily. The same steers were implanted in each experiment. At the conclusion of each experiment metabolic rate was measured after a 72 h fast. 2. In the first experiment control and implanted steers had similar rates of LW loss (0.57 and 0.59 kg/d respectively). Implanted steers had significantly (P less than 0.01) lower feed intakes (12.8 v. 10.9 g dry matter (DM)/kg LW), significantly (P less than 0.01) lower fasting metabolic rates even after adjustment for intake (83.3 v. 74.5 kJ/kg per d) and significantly (P less than 0.01) lower plasma insulin concentrations (24 v. 19 mu units/ml). Differences in plasma concentrations of free 3,5,3'-triiodothyronine (T3), non-esterified fatty acids and urea-nitrogen were not significant. 3. In the second experiment intake of the supplemented diet was similar in both control and trenbolone acetate-treated steers (19.5 and 20.0 g DM/kg LW respectively). LW gains were 0.23 and 0.41 kg/d for control and implanted steers respectively, the difference being significant (P less than 0.05). Fasting metabolic rate (76.9 v. 70.7 kJ/kg per d) was significantly (P less than 0.05) lower in implanted steers.

Effect of lipid solvents on cutaneous moisture loss.

Application of various lipid solvents and dimethyl sulphoxide to the skin of cattle, sheep, eland and African buffalo exposed to an air temperature of 20 degrees C caused an increase in cutaneous moisture loss. The effect did not occur after exposure to an air temperature of 40 degrees C or after adrenaline administration. Blockage of sweating by either bethanidine or phenoxybenzamine did not affect the response. Camel, donkey, dog and man showed no increase in cutaneous moisture loss after lipid solvent application to the skin. It is concluded that lipid solvents directly stimulate the secretory cells of the sweat glands of members of the family Bovidae and that this is not due to the release of transmitter substance nor to stimulation of adrenergic receptors, but is due to direct stimulation of the sweat glands themselves.