Plasma constituents in Nguni cows over forty-eight hours.

Plasma constituents were investigated at ninety minute intervals over a forty-eight hour period on four unrestrained Nguni cows (in small cubicles) in order to study the presence or absence of rhythms. No circadian, ultradian or diurnal rhythm was found for any of the parameters investigated. Basal values over a forty-eight hour period were obtained for certain plasma constituents. These values are of use for studies relating to the effects of stress in cattle.