Plasma haptoglobin for ovulatory (OV) and non-ovulatory (NOV) cows. Hon CheongSoon FilhoOcilon G. Sá Absalon-MedinaVictor A. SchneiderAugusto ButlerW. R. O. GilbertRobert 2017 <p>NOV cows have significantly higher levels of haptoglobin compared with OV cows.</p>