| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 2073824 | Animal Reproduction Science | 2010 | 7 Pages |
The aim of the present study was to evaluate the efficacy of an Ovsynch protocol in the cyclic and non-cyclic Egyptian buffaloes in the summer. The present study was carried out on 21 Egyptian pluriparous buffalo cows (11 cyclic and 10 acyclic) and 8 heifers (5 cyclic and 3 acyclic). All animals were administered 100 μg GnRH i.m. at Day 0, 500 μg of PGF2∝ i.m. at Day 7 and a second dose (100 μg) of GnRH i.m. at Day 9. Ovarian structures of the animals were recorded by means of transrectal ultrasonography (6–8 MHz linear-array transducer) daily from Day 0 (before treatment) to Day 9 (the second GnRH administration) and thereafter, at 12-h interval till ovulation or for a maximum of 48 h. After ultrasound examination, a blood sample was taken daily from each animal for progesterone analysis. The buffalo cows were inseminated at 16–20 h after 2nd GnRH administration.After the first administration of GnRH, 46% (5 of 11) of cyclic and 50% (5 of 10) of acyclic cows and 40% (2 of 5) of cyclic and 33% (1 of 3) of acyclic heifers responded by ovulation or luteinization of the follicles. The mean diameters (±S.E.M.) of the follicles in the responding cows and heifers were significantly higher than those in non-responding animals (9.7 ± 0.4 mm vs. 6.7 ± 0.6 mm, P < 0.0001; 11.1 ± 1.5 mm vs. 7.3 ± 0.7 mm, P < 0.05, respectively). After the second administration of GnRH, 81% (9 of 11) of cyclic and 60% (6 of 10) of acyclic cows and 80% (4 of 5) of cyclic and 33% (1 of 3) of acyclic heifers ovulated, respectively. Ovulations occurred earlier (P = 0.059) and over a wider range of time in the non-cyclic cows (26 ± 4.8 h; range: 12–36 h) and in a heifer (12 h,) than in the cyclic cows (34.7 ± 1.3 h; range 24–36 h) and heifers (33 ± 3 h; range: 24–36 h). The conception rate was 18% (2 of 11) and 0% (0 of 10) in cyclic and non-cyclic cows, respectively. In conclusion, the Ovsynch protocol could be used effectively for synchronization of ovulation in cyclic cows and heifers in summer.
