Effect of different hormonal treatments as therapeutic procedure on repeat breeder buffalo heifers

الملخص EN

Total of 30 Egyptian buffalo heifers (20-25 months and 340-360 kg) failed to conceive after 3 services (repeat breeder heifers) were exposed to three hormonal protocols after exhibiting the 4th estrous cycle.

In the 1st protocol, heifers (n = 10) were injected with GnRH on day of estrus and service.

In the 2nd protocol, heifers (n = 10) were injected with GnRH on day of estrus (0 day), followed by PGF2α on day 7.

Heifers displaying estrus within 48 hr.

of PGF2α injection were served, while those did not show estrus within 48 h were injected with a second dose of Gn RH on day 9 and served on day 10.

In the 3rd protocol, heifers (n = 10) were injected with 1st PGF2α injection starting on day 6 after exhibiting the 4th estrous cycle.

Animals exhibiting estrus within 72 hr.

after 1st PGF2α injection were served, while those did not exhibit estrus were re-injected after 11 days of the 1st injection with 2nd PGF2α and served 24-48 hr.

later.

Pregnancy was diagnosed by ultrascan after 35.d of service.

At service, diameter of the largest follicles was recorded for the 1st and 2nd protocols, while diameter of corpus luteum (CL) was recorded for the 3rd protocol using ultrascan.

Blood samples were collected pre-and post- hormonal injections of each protocol for determination of progesterone (P4) concentrations in blood serum of all animals.

Results showed that conception rate (CR) in the 1st protocol was 80% and mean diameter of the largest follicle was 13.25 and 9.10 mm in conceived and non-conceived heifers, respectively.

Concentration of P4 was lower pre-treatment and at service in conceived heifers (3.063 and 0.182 ng / ml) than in non-conceived heifers (5.828 and 0.296 ng / ml), while, an opposite trend was observed post-treatment (5.802 and 3.541 ng / ml), respectively.

In the 2nd protocol, after PGF2α injection, estrus rate was 50 % (within 48 h) and CR was 80 % based on inseminated animals.

Mean diameter of the largest follicle was 8.3 and 7.0 mm in conceived and non-conceived heifers, respectively.

After the 2nd GnRH and blind service, CR was 60 % and mean diameter of largest follicle was 8.9 and 4.7 mm in conceived and non-conceived heifers, respectively.

The final CR after GnRH-PGF2α-GnRH was 70 %.

The 1st GnRH injection increased P4 concentration in all treated heifers, while PGF2α injection reduced P4 level to 0.433 and 1.420 ng / ml in conceived and non-conceived heifers, respectively.

In the 3rd protocol, estrus rate was 50% within 72 h after the 1st PGF2α injection and CR was 80 %.

Mean diameter of CL at service was 11.3 mm.

All heifers (100 %) injected with 2nd PGF2α exhibited estrus (within 48-72 h), served and conceived.

Mean CL diameter was 10.6 mm.

For the whole 3rd protocol (after both PGF2α injections), CR was 90 % and mean diameter of CL was 10.9 mm.

The 3rd protocol had the cheapest cost and the highest conception, followed by the 1st protocol, while the 2nd protocol showed the highest cost.