SADASIVA RAO, K(MAJOR)SRINIVAS, MDEVI PRASAD, VVENKATESWARLU, M2019-07-162019-07-162019-04http://krishikosh.egranth.ac.in/handle/1/5810114867THESESThe present investigation entitled “Studies on efficacy of GnRH and hCG during mid luteal stage of the cycle in repeat breeder Graded Murrah buffaloes (Bubalus bubalis)” was taken up by screening 130 repeat breeder lactating buffaloes to study the causes of repeat breeding. The efficacy of GnRH (Group 1 – 10μg of GnRH 8 hours before AI at observed estrus and Group 2 – 10μg of GnRH 8 hours before AI at observed estrus and 13th day of post insemination) and hCG (Group 3 – 1500 IU of hCG 8 hours before AI at observed estrus and Group 4 – 1500 IU of hCG 8 hours before AI at observed estrus and 13th day of post insemination) protocols for enhancement of conception rates were studied in 60 repeat breeding Graded Murrah buffaloes in comparison with normal cyclical buffaloes as untreated control (Group 5). The causes of repeat breeding in Graded Murrah buffaloes reared under rural climatic condition includes, repeat breeders without any palpable abnormalities in the genital tract, subclinical endometritis and tubal blockage was recorded to be 60, 66, 4 buffaloes and the percentage was 46.15, 50.78, 3.07, respectively among 130 repeat breeder buffaloes examined. White side test and PSP dye test could be effectively used to diagnosis the subclinical endometritis and tubal blockage, respectively. The mean length of estrous cycle in repeat breeders and normal cyclical buffaloes was 21.68±0.39 and 22.60±0.31 days; duration of estrus was 22.10±0.33 and 24.39±0.08 hours; intensity of estrus 13.42±0.37 and 15.4±0.63 points, respectively. There was no significant difference (P<0.05) in length of the estrous cycle, whereas significantly (P<0.05) less in duration of estrus and lower intensity of estrus in repeat breeder buffaloes when compared with that of normal cyclical buffaloes. Repeat breeder Graded Murrah buffaloes exhibited lowered levels of mean haemoglobin (8.61±0.20 gm%), PCV (35.21±0.99 %) when compared to normal cyclic buffaloes. Further, biochemical parameters viz., mean serum glucose (48.26±2.83 mg/dl), calcium (7.21±0.18 mg/dl), phosphorus (4.44±0.12 mg/dl), total protein (6.57±0.09 g/dl) and cholesterol (85.57±1.90 mg/dl) concentration also showed lowered levels in repeat breeder buffaloes when compared to normal cyclical buffaloes. The conception rates of repeat breeding Graded Murrah buffaloes in Group 1, 2, 3, 4 and control group (Group 5) were recorded to be 40.00, 46.67, 53.33, 66.67 and 42.85 per cent, respectively. It was concluded that all the treatments except that of Group 1 could improve the conception in repeat breeder buffaloes compared with that of normal cyclical buffaloes. However, hCG treatment groups revealed higher per cent of conception rates (53.33 and 66.67%) when compared with that of GnRH treatment groups (40.00 and 46.67%). The human chorionic gonadotropin administered at observed estrus and on 13th day post insemination could effectively improve the conception rates in repeat breeding Graded Murrah buffaloes.ennullThesis