Abstract:
Sub-clinical endometritis (scEndo) in early lactation affects ovarian follicle dynamics, delays a return to cyclicity, with changes in plasma and follicular fluid (FF) amino acid concentrations around the time of rebreeding. This study examined the effect of resolving scEndo in early lactation on plasma and FF oestrogen, progestagen, androgen and corticosteroid concentrations at the time of rebreeding in 46 dairy cattle. On D42 postpartum, cows were classified as having scEndo, clean or having resolved scEndo cased on uterine cytology on D21 of > 18% polymorphonuclear (PMN) cells amongst uterine nucleated cells. On D42 and D63 follicular and plasma samples were collected and steroid concentrations analysed. On D21 and D42, 35% and 7% of cows respectively were classified as having scEndo, with 81% of scEndo cows having self-resolved the infection by D42. In those cows that resolved scEndo, none of the plasma or FF steroid concentrations changed between D42 and D63, except for plasma progesterone (P = 0.08). Using a low (4%PMN) threshold to classify scEndo did not identify any significant changes in steroid concentrations. In contrast to previously described changes in plasma and FF amino acid concentrations, there were no significant effects on steroid concentrations when cows self-resolved a sub-clinical uterine infection.
