B.K. SinghAkhtar Mohammad Hasib2023-11-072023-11-071988https://krishikosh.egranth.ac.in/handle/1/5810200533Enzyme Immunoassay of progesterone in sera and milk samples of cattle and buffaloes was carried out during the present investigation. Investigation was done by indirect method of EIA using alkaline phosphatase and horse-radish peroxidase as label. In addition, amplifier system was also used in one of the groups. It was observed that with the use of amplifier the color development was more marked as compared to the use of either of the two enzymes. Secondly, values of progesterone, either in serum or milk were not different from the values when the two enzymes were used as label. Progesterone profile was estimated at regular intervals in sera and milk samples during oestrous cycle of cows, during early pregnancy and during par parturient period in cows and buffaloes. In addition, serum and milk progesterone values were estimated on alternate day during early pregnancy of cows from day 0 of oestrus to day 40. Ten cows were screened to find out the progesterone level in serum and milk during the complete oastrous cycle and it was observed that the duration of the cycle was of 20, 21 and 23 days in 2, 6 and 2 covs, respectively. The progesterone level on the day of oestrus in serun in all the three types of sexual cycles was low and a gradual increase in serum progesterone concentration was observed with peak on D 14, D 16 and D 19 in 20, 21 and 23 day cycles, respectively. Milk progesterone level also showed a similar pattern. In the adjusted oestrous cycle of 21 days the peak average progesterone value in serumEnglishThesis