The plasma progesterone curve during the oestrus cycle of trypanotolerant cattle breeds in Cote-d’Ivoire

Abstract

During 45 days, blood samples were collected daily on 12 Ndama and 12 Baoulé cycled cows for dosing plasma concentration. The cycle length observed was 20.4 days (Ndama) and 21.4 days (Baoulé). The mean level of progesterone low on the day of heats (0.6 ng/ml), rose slowly from 1.3 to 1.4 ng/ml per day. It reached a plateau on day 8 (Ndama) or 9 (Baoulé) until day 17 of the cycle with a mean level of 9.5 ng/ml (Ndama) or 9.3 ng/ml (Baoulé). The fall in progesterone was quick after the day 17 with 3 ng/ml per day. The phase with less than 2 ng/ml lasted 5.7 days (Ndama) and 5.9 days (Baoulé), with a deviation of 4 to 9 days. The phase with more than 2 ng/ml lasted 14.5 days (Ndama) or 14.9 days (Baoulé), with a deviation of 13 to 19 days. Some atypical cases were found, thus progesterone level exceeded 3 ng/ml on the day of heats in about 12 % of the latter. It is concluded that the level of progesterone can be used in these trypanotolerant breeds in Côte-d’Ivoire to study cyclicity (puberty, post partum ovarian activity) and to perform early pregnancy diagnosis 21 to 24 days after artificial insemination.