Steroid precursors, steroids, neuroactive steroids, and neurosteroids concentrations in serum and saliva of healthy neonatal heifer Holstein calves

Background Persistence of high neurosteroid concentrations in blood is associated with neonatal encephalopathy and septicemia in foals. This has not been investigated in calves. Objectives To determine concentrations of steroid compounds in serum and saliva within the first 48 hours after birth in healthy neonatal calves, identify potential markers for disease, and investigate the association between serum steroid compounds concentrations in calves and their respective dams within 2 hours after birth. Animals Twelve healthy neonatal heifer Holstein calves and their dams. Methods Prospective study. Serum and saliva were collected from calves at 2, 6, 24, and 48 hours after birth. Steroid compounds were analyzed using liquid chromatography‐mass spectrometry. A nonlinear regression model was used to determine half‐lives of the neurosteroids. Serum concentrations of neurosteroids between the cows and calves were compared using the Wilcoxon signed rank test. Results Half‐lives (95% confidence intervals) of dehydroepiandrosterone (DHEA) and 17α,20α‐dihydroxyprogesterone in calf serum were 2.9 (2.1, 4.3), and 2.1 (1.3, 3.0) hours, respectively. Pregnanediol in saliva had a half‐life (95% confidence interval) of 24.5 (14.2, 66.5) hours. Serum DHEA (1718.7 ± 2313 vs 57.7 ± 44) and 17α,20α‐dihydroxyprogesterone (207.8 ± 198.2 vs 43.5 ± 33.5) concentrations respectively were higher ( P < .05) in calves compared to cows. Conclusions and Clinical Importance Dehydroepiandrosterone, 17α,20α‐dihydroxyprogesterone, and pregnanediol could be potential markers of disease in neonatal heifer calves with unexplained failure to thrive or encephalopathy. However, because of the wide 95% confidence interval of the half‐life, pregnanediol in saliva might not be a potential marker.