Hair cortisol concentrations in different breeds of cows: Comparison of hair from unshorn and previously shorn areas and from various regions of the body.

Abstract

Introduction: The goals of this study were to investigate hair cortisol concentration (HCC) in seven different breeds of cows, to establish reference intervals for HCC in Brown Swiss cows and to compare cortisol concentrations of hair collected from four different areas of the body. Three groups of cows were used. Group 1 comprised 70 healthy cows representing four dairy breeds (Brown Swiss, Swiss Fleckvieh, Holstein Friesian, Water Buffalo) and three beef breeds (Raetian Grey, Limousin, Highland). Group 2 consisted of 60 healthy Brown Swiss cows in which two different hair samples were collected from the thoracic region to establish reference intervals; A samples consisted of hair that had grown for one month in a pre-clipped area, and B samples consisted of hair from a previously unshorn area. Group 3 comprised 21 healthy Brown Swiss cows, in which HCCs were measured in A and B samples from four different body regions (neck, shoulder, thorax, rump). Liquid chromatography tandem mass-spectrometry was used for cortisol measurement. In group 1, the highest HCCs were measured in Holstein Friesian cows at 1,75 pg/mg, which was significantly higher than those of the Brown Swiss, the Swiss Fleckvieh and the Water Buffalo cows. Hair cortisol concentration and daily milk yield of the 40 dairy cows were highly correlated (r = 0,57, P < 0,01). In group 2, the HCCs of 77 % of the A samples and 85 % of the B samp-les were below the laboratory's limit of quantification (LOQ) of 0,50 pg/mg and the results were expressed semiquantitatively as.