| dc.description.abstract | The concentration of testosterone in the plasma of most male domestic and laboratory animals, for example bulls (Thibier, 1975), boars (Andresen, 1976) and rats (Mock, Kamel, Wright & Frankel, 1975) is usually in excess of 10 nmol/l. In seasonal breeders such as sheep, values as high as 90 nmol/l have been reported in the summer before the breeding season (Falvo, Buhl, Reimers, Foxcroft, Dunn & Dziuk, 1975). In contrast, Katongole (1971) found that in a temperate summer, plasma testosterone concentrations in Equidae, including the donkey, were 4·5 nmol/l or less. It was, therefore, of interest to investigate whether the basal plasma testosterone concentrations in donkeys would be higher and more stable in the tropics.
Six potent adult male donkeys were kept in a large pen, fed rhode grass and given free access to salt and water. Blood | en |
