Metabolic markers for purulent vaginal discharge and subclinical endometritis in dairy cows

This study compares serum markers for systemic inflammation, and liver, mineral, and energy status in samples obtained -7, 1, 3, 5, 7, 14 ± 1, 21 ± 1, and 35 d relative to calving from healthy dairy cows and those diagnosed with purulent vaginal discharge (PVD) or subclinical endometritis (SCE). Metabolites and markers measured in serum were total calcium, total protein, albumin, globulin, cholesterol, urea, glucose, gamma-glutamyl transferase, aspartate aminotransferase, glutamate dehydrogenase, β-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), haptoglobin (Hp), and insulin-like growth factor-1 (IGF-1). Holstein cows with no recorded clinical disease were classified healthy (neither PVD nor SCE; n = 38), PVD (n = 10) or SCE (n = 10) at 35 d postpartum. The cut-point for PVD was mucopurulent vaginal discharge or worse, measured with Metricheck, and for SCE > 5% endometrial polymorphonuclear cells (PMN). Purulent vaginal discharge and SCE were mutually exclusive categories. The association of each serum marker with reproductive tract health classification was fitted in mixed linear regression models, accounting for repeated measures, sampling day, parity, BCS, and interactions of reproductive tract status and day. Serum Hp concentrations were greater at 3, 5, 7, and 14 ± 1 d postpartum for SCE and at 7 and 35 d postpartum for PVD than in healthy cows. Albumin concentrations were lesser for PVD than healthy at 14 ± 1 d postpartum and lesser for SCE than healthy at 35 d postpartum. The week before calving, SCE had lesser total calcium than healthy cows, and at 7 and 14 ± 1 d postpartum PVD had lesser total calcium than healthy cows. At 14 ± 1 d postpartum, serum NEFA, BHB, and globulin were greater, and IGF-1 lower for SCE than PVD or healthy cows. For all other metabolites, no differences were found. Before diagnosis, PVD or SCE had more indication of postpartum systemic inflammation (high Hp and low albumin) than healthy cows, and markers of energy status were more compromised in SCE than in PVD or healthy cows. This supports the hypothesis that SCE is associated with maladaptation to postpartum metabolic demands and with metabolic inflammation.