Abstract
This study aimed to evaluate the efficiency of treatment of postpartum anestrous Egyptian buffaloes in summer season. Protocols of controlled internal drugs (CIDR) as a source of exogenous progesterone were included with some hormonal preparations such as GnRH, PGF2α and estradiol benzoate (EB) for monitoring the resumption of ovarian cyclicity based on assessment of different reproductive performance parameters (EIR, TCR, PR).
The study was conducted on 120 postpartum anestrous buffalo-cows, which were diagnosed on basis of case history (>120 days postpartum). Postpartum rectal palpation of both ovaries was performed together with collection of two blood samples with 10 days interval for assessment of serum progesterone level. Buffaloes were assigned to five groups and a control group. Buffaloes in treatment 1 (n=20) received on day (0) GnRH (10μg) +CIDR (inserted intravaginal), 25mg PGF2α on day (7), CIDR was removed on day (8), 2nd dose of GnRH on day (9). Buffaloes in treatment 2 (n=20) received on day (0) GnRH (10mg)+CIDR, CIDR was then removed+2nd dose of GnRH on day (7). Buffaloes in treatment 3 (n=20) received CIDR on day (0), CIDR was removed+PGF2α (25mg) injected on day (7). Buffaloes in treatment 4 (n=20) CIDR inserted +GnRH (10mg) on day (0), CIDR removal+25mg PGF2α on day (7), 24hrs EB was injected. Buffaloes in treatment 5 (n=20) CIDR for 7 days then removed. Buffaloes in control group (n=20) had no treatment.
Results in treatment 1 (P4, 0.86±0.1) were; EIR (80%), TCR (84.2%) and PR (80%). While, in treatment 2 (P4, 0.86±0.10) EIR (55%), TCR (68.42%) and PR (65%). Results in treatment 3 at P4 level (0.79 ±0.10) were; EIR (70%), TCR (72. 2%) and PR (65%). Also, in treatment 4 (P4, 0.87±0.10) EIR (85%), TCR (78.9 %) and PR (75%). While in treatment 5 (P4, 0.85±0.07) were; EIR (45%), TCR (57.14 %) and PR (40%). In control (group 6) at P4 level (0.93 ±0. 09) the results were; EIR (15%), TCR (33.3%) and PR (5%).
In conclusion, the results indicated that addition of GnRH and PF2α to progesterone based CIDR protocol (CIDR-ovsynch) substantially improves the EIR, TCR and PR in postpartum anestrous buffaloes than CIDR protocol alone and other treated groups in comparison to control.

Key words: Buffaloes, Ovsynch, Anestrous, CIDR, GnRH, PGF2α, EB; P4.