Impact of redox status of donor cows before superovulation treatment on in vivo embryo production

This study investigated the relationship between oxidation and antioxidation parameters before superovulation (SOV) treatment and embryo recovery in donor cows. The relative redox status of the 61 donor cows was evaluated based on the median values of diacron-reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP) measurements (d-ROMs of 100 U.CARR; BAP of 2413 $\mu$ mol L ${}^{-1}$ ) before SOV treatment. Following this, the animals were divided into four groups: cows with low d-ROMs but high BAP were assigned to the "LH" group ( $n=11$ ), cows with high d-ROMs and BAP were assigned to the "HH" group ( $n=20$ ), cows with high d-ROMs but low BAP were assigned to the "HL" group ( $n=10$ ), and cows with low d-ROMs and BAP were assigned to the "LL" group ( $n=20$ ). Embryos were collected from superovulated cows 6 d after artificial insemination. The percentages of fertilised, transferable, and Code-1 embryos were significantly higher ( $P<0.05$ ) in the HH group than those in the HL group. The HH group had the highest mean values for all embryo recovery results. Our results suggest that the redox status of donor cows before SOV treatment affects embryo recovery, as cows with high levels of both oxidative and antioxidative status have better embryo production.