Comparative relations between progesterone blood concentration and appearance of oestrus in cows

The timely detection of oestrus presents an important professional procedure with which cattle farmers, in addition to veterinarians, are very often faced, because failure to detect oestrus poses a big economic problem. The objective of this work is to evaluate the efficacy of discovering oestrus in cows by determining the progesterone concentration (P4) in blood plasma. This experiment covered 22 animals, including 15 cows and 7 heifers, in which spontaneous oestrus was discovered. P4 concentration was determined using the ELISA test in samples of blood taken from the animals at the moment of insemination. Of the 15 cows, four cows (26.6%) were not inseminated at the optimal time, and the P4 level in these animals was higher than 1 ng/ml. All the heifers showed a progesterone concentration of over 1 ng/ml, and a percentage of conception which was 85%. The high P4 level in heifers at the moment of insemination could also be a consequence of stress caused by the regrouping and separating of the animals. Even though the heifers were under stress, which is indicated by the high progesteronemia values at the moment of insemination, the percentage of conception among them was beyond expectations. Therefore, the determination of P4 values at the moment of insemination is a suitable method for improving reproduction management on cattle farms. Inappropriate treatment of cows which are expected to show oestrus can cause stress and an increase in the values of the blood concentration of P4. On the grounds of the results obtained in this work, no negative influence of stress on the insemination results in heifers was observed