Longitudinal fecal cortisol metabolite concentrations across the transition period in multiparous dairy cows under commercial conditions

Abstract This longitudinal observational field study characterized fecal cortisol metabolite (FCM) concentrations across the transition period in multiparous Holstein-Friesian dairy cows under commercial conditions. The dataset comprised 38 clinically healthy cows from four farms, with 19 sampled in winter and 19 different cows in summer. Each cow was sampled at 1 month and 1 week before parturition and 1 week and 1 month after parturition, yielding 152 observations. FCM concentrations were quantified using an 11-oxoetiocholanolone enzyme immunoassay and analyzed using a mixed-design repeated-measures general linear model, with stage as the within-cow factor and season and farm as between-subject factors. FCM concentrations differed across transition stages (P < 0.001); estimated marginal means (95% CI) were 421.1 (363.5–478.8), 342.2 (288.8–395.6), 238.5 (205.6–271.5), and 226.1 (171.1–281.0) ng/g dry feces, respectively. Neither season (P = 0.815) nor the Stage × Season interaction (P = 0.213) was significant. Significant farm-related effects and interactions indicated heterogeneity among the sampled herds without establishing causal effects of management practices. Temperature-humidity index values described environmental conditions only. These findings indicate an overall prepartum-to-postpartum decline, although not all pairwise comparisons were significant. Longitudinal FCM profiling may complement investigations of adrenocortical activity during the transition period. Further studies integrating endocrine, clinical, productive, behavioral, and environmental indicators are needed to establish its relevance to dairy cow health, productivity, and welfare.