Assessment of fertility by monitoring changes in plasma concentrations of progesterone, oestradiol-17β, androgens and oestrone sulphate in suboestrous buffalo cows treated with prostaglandin F2α

Forty-eight suboestrous buffalo cows with palpable corpora lutea were used to evaluate the effect of a double prostaglandin F2α injection and to characterize the pattern of plasma progesterone, oestradiol-17β, androgens and oestrone sulphate following fertile and infertile matings in the induced oestrus. 48 cows studied, 37 (77%) exhibited oestrus within 5 days of the second PGF2α injection and 17 (46%) conceived. PGF2α, induced luteolysis in 42 animals with active corpora lutea as evidenced by the dramatic decreases in plasma progesterone concentrations within 96 h after the second injection (day 0). The non-responding group showed the lowest plasma concentrations of oestradiol-17β and total androgens during days 3–5 and 10–14 of the sampling period. In contrast, the pregnant cows had significantly (P < 0.05) higher plasma concentrations of progesterone (on day 10) and oestrone sulphate (on day 18) than those of the non-responding and non-pregnant groups. An examination of the clinical findings and plasma patterns of progesterone, oestradiol-17β and androgens in the non-pregnant cows indicated that failure of corpus luteum formation (nine cows), failure of luteolysis (six cows) and delayed ovulation (five cows) are factors responsible for the low conception rate observed following treatment of suboestrous buffalo cows with PGF2α.