Superovulation with PMSG (eCG)‎ and embryo transfer of Egyptian buffaloes

الملخص EN

The present study was conducted to assess the effects of different superovulatory regimens using pregnant mare serum gonadotropin (PMSG) (eCG equine chorionic gonadotrophin) and influence of administration of GnRH or rbST to recommended superovulatory regimens as well as determination of pregnancy rate after embryo transfer of different superovulatory regimens. A total of 106 buffaloes were used in the present study.

They were clinically healthy and with good body conditions.

The Estrous synchronized by administration of prostaglandin (double intramuscular (I.

m) injections 11 day apart).

A total of 76 buffaloes (3 experiments) were used to evaluate the efficacy of superovulation by eCG.

Experiment 1 (43 animals), the animals were divided into 5 groups after synchronization using PGF2and injected with different doses of eCG (GI : 1500 IU, GII : 2000 IU, GIII : 2500 IU, GIV : 3000 IU, GV : 3500 IU) at mid luteal phase of estrous cycle.

Exper.

2 : was designed to evaluate the effect of GnRH on the superovulatory response.

A total of 8 buffaloes injected with 3000 I.U eCG (control) as recommended dose from 1st exp.

and 9 buffaloes were injected with 3000 IU eCG and 20 μg GnRH at the time of insemination.

Exper.

3 : was conducted to evaluate the effect of rbST on the superovulatory response.

Eight buffaloes received 3000 I.U eCG (control) and other 8 buffaloes received 3000 eCG + 500 mg rbST. Exper.

4 : was carried out to determine the pregnancy rate of recovered transferable embryos of previous experiment, a total of 30 fresh buffalo embryos were transferred to prepared recipient in 5-6 days of estrous and pregnancy diagnoses was conducted after 30 days after transfer. The results of the present study indicated that the using of eCG for superovulation in buffalo characterized by low ovarian response and low embryo recovery in all treated groups with the lowest ovarian response and embryo yields in group I (3.12 ± 0.22 follicles, 0.0 embryo) and the highest response and embryo recovery in group 4 (7.42 ± 42 follicles and 1.14 ± 2.6 embryo).

Moreover, the results revealed that administration of 20 μg GnRH or 500 mg rbST do not improve superovulatory response in buffaloes.

The pregnancy rate after embryo transfer did not show significant difference between GIII and GIV (2500 IU eCG vs 3000 IU). However, administration of 20 µg GnRH and 500 mg rbst improved the pregnancy rate by 3 3% and 50 %, respectively..