FOLLICULAR GROWTH PATTERN IN BUFFALOES SYNCHRONIZED TO ESTRUS WITH PROGESTERONE IMPREGNATED INTRAVAGINAL SPONGES

A study was conducted in regular cyclic Murrah buffaloes which were free from any anatomical and reproductive disorders. Progesterone impregnated polyurethane intravaginal sponges containing 1.5g of natural micronised progesterone were aseptically inserted into vagina. Theses sponges were placed in situ for 9 days and removed manually on the 10 th day. Ultrasonography of the ovaries was done in all the animals on Day 0 (day of insertion of the sponge), Day 3, 10 (day of removal) and at induced estrus transrectally using a real time ultrasound scanner equipped with a linear array 5- 7.5 MHz frequency transrectal transducer. Blood samples collected during these days were analyzed for progesterone levels by radioimmunoassay method. All the animals retained vaginal sponges up to 10 days. There was no abnormal discharge noted upon removal of the sponge and all the animals were induced to estrus within 48 to 72 hours after sponge removal. Ultrasonographic study revealed that on day of insertion of sponge, all the animals had corpus luteum No dominant follicles were noticed in these animals. On day-3, corpus luteum was present with no appreciable further growth from day - 0. No dominant follicles were noticed in these animals. On day of sponge removal, all the animals had a developing dominant follicle. On the day of estrus, all the animals showed the presence of a well developed mature graffian follicle of size ranging from 10 x 7 mm to 12x 11 mm. The progesterone hormone assay revealed that the mean plasma progesterone level on day-0 was 3.7±0.70 ng/ml, which increased to 10.4±1.29 ng/ml on day-3. On the day of sponge removal, the progesterone level was 2.62±0.28 ng/ml which further decreased to 0.47±0.08 ng/ml at estrus. The results indicate that the progesterone sponges helped in maintaining the progesterone levels with peak values reaching on day 3 of insertion of sponge. During the period of intra vaginal sponge the