Abstract

The measurement of immunoreactive urinary corticosteroids was validated as a method of monitoring adrenocortical activity in lactating dairy cows. The physiological relevance of the technique was validated by demonstrating that (i) injection of ACTH led to a significant increase in plasma and urinary corticosteroid concentrations, and (ii) the translocation of cows from pasture to a barn facility resulted in a 1.1- to 2.5-fold increase in urinary cortisol concentrations. Plasma cortisol concentrations exhibited a 15- to 33-fold increase above basal concentrations 30 mins after ACTH administration (2.98±0.35 vs 63.7±3.9 ng/ml plasma; mean±SEM; P<0.01). Monitoring urinary corticosteroid concentrations is a valid tool for studying and evaluating adrenal activity and acute stress in cattle.

CJ, Morrow, ES Kolver, GA Verkerk, and LR Matthews

Proceedings of the New Zealand Society of Animal Production, Volume 60, Hamilton, 218-221, 2000