Changes in plasma oxidative stress biomarkers in dairy cows after oestrus synchronisation with controlled internal drug release (CIDR) and prostaglandinF2a (PGF2a)

This study was designed to evaluate the plasma profiles of oxidative stress biomarkers, progesterone and ovarian follicle diameter in ovulatory versus an-ovulatory cows. Twenty cows were synchronised using controlled internal drug release (CIDR) and prostaglandinF2a (PGF2a) protocol. Plasma samples were analysed for progesterone (P4), oxidative stress (OS) biomarkers; reactive oxygen metabolites (ROMs), biological antioxidant potential (BAP), oxidative stress index (OSI = ROMs/BAP · 100), advanced oxidation protein products, ceruloplasmin and glutathione (GSH). Plasma P4 concentration was greater in ovulated cows 24 hours (h) after PGF2a treatment but lower 48 h after PGF2a treatment compared with that of an-ovulated cows at those sampling sessions (P < 0.05). Ovulated cows were diagnosed with greater ovarian follicle diameter compared with that of their herd mates not diagnosed for ovulation. Significant interaction of time of PGF2a treatment and ovulation status (ovulatory versus an-ovulatory) with the plasma concentrations of OSI, BAP and GSH were observed. Ovulated cows had significantly lower BAP compared with that of an-ovulated cows (P < 0.05) 9 h, 48 h, 60 h and 128 h after PGF2a treatment. Plasma concentrations of GSH were lower (P < 0.05) in ovulated cows than that of an-ovulated cows 60 h and 96 h after PGF2a treatment. However, OSI was greater (P < 0.05) in ovulated cows than that of an-ovulated cows 9 h, 48 h, 60 h and 128 h after PGF2a treatment. Significant associations were observed between OS status and sampling time. Oxidative stress status may have important physiological role in facilitating the ovulation process in oestrus synchronised dairy cows.