Hypophyseal and gonadal response of late maturing Murrah buffalo heifers(Bubalus bubalis) receiving GnRH,PGF2_ and eCG
2004
Singh, C. | Madan, M.L. (National Dairy Research Institute, Karnal (India))
The pattern of hypophyseal and gonadal hormone release and gonadal potential in terms of folliculogenesis and ovulation was studied in 4 late maturing Murrah buffalo heifers. They were injected with 200 æg of GnRH intravenously at 42 months of age (day 0), PGF(2)Alpha intramuscularly on day 45 (30mg) and day 57 (25 mg), eCG (2500 IU,IM) on day 55 and GnRH (200æg, iv) at induced estrus on day 59. Blood samples were collected via jugular catheter for estimation of hormones. The pretreatment plasma estradiol, progesterone, FSH and LH concentration were 7.64ñ1.69 pg/ml. 0.20ñ0.04 mg/ml, 9.22ñ1.50 mg/ml and 0.63ñ0.04 mg/ml, respectively, on day 0. Estradiol concentration increased to 20.76ñ1.10 pg/ml on day 13. All heifers were detected in estrus between day 25 and 35. The eCG administration (day 55) induced multiple follicular development and estrus on day 59. Total number (meanñSE) of palpable follicles and ovulation at induced estrus (day 59) were, respectively, 4.00ñ0.00 and 2.25ñ0.25. GnRH injection triggered significanlty (P0.01) in increased release of FSH and LH within 5 min. Peak concentration of FSH (127.80ñ5.51 ng/ml) and LH (26.94ñ2.41ng/ml) after first (56.72ñ8.11 ng/ml) detected following second GnRH injection (day 59) at inducted estrus. The peak release of both FSH(r
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