Evaluation of serum cortisol, metabolic parameters, acute phase proteins and faecal corticosterone as indicators of stress in cows.

To assess the validity of laboratory parameters in blood and faeces as indicators of stress in cows, concentrations of cortisol, non-esterified fatty acids (NEFAs), 3-hydroxybutyrate, glucose, triglycerides, cholesterol, serum amyloid A (SAA) and haptoglobin in serum, as well as corticosterone in faeces, were determined in two breeds of cattle (Alberes and Bruna dels Pirineus) under different systems of housing and feeding. Serum cortisol concentrations were markedly elevated in the Alberes group, probably because they were less habituated to human handling. Corticosterone concentrations in faeces were significantly increased in the Bruna dels Pirineus cattle on Alberes pastures. Concentrations of NEFAs and cholesterol were significantly elevated in the Alberes cows, indicating an adrenergic stimulus of lipolysis or the existence of nutritional stress. SAA concentrations were significantly higher in groups living in hardy conditions, whereas there were no significant differences in haptoglobin between the three groups.