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Abstract
The present work was designed to establish the effect of different estrus synchronizing regime on the induction of ovarian cyclicity and ovulation in early and late post partum periods in buffalo-cows.1- Expirment I : “Induction of ovulation during early postpartum period (early intervention)” by using GnRH-PGF2α-GnRH Ovysynch protcol): A total number of six buffalo-cows were assigned into two groups : (i) treated group (n=3) which were given 20 μg of a GnRH analogue ; Buserelin acetate ; on Day 21 postpartum (d0t) ; 500 μg of synthetic PGF2α; Cloprostenol ; on day 28 postpartum (d7t) followed by a second of 20 μg of a GnRH analogue two days later (d9t).For the control group (n=3), all animals were injected by saline in similar to the equivalent dose of the hormonal treatment and at the same recommended regime as the treated group.Ovaries of all animals were daily investigated with ultrasound from Day -1 to Day 9 and then after every 12 hrs until detection of ovulation or approximatly 48 hrs after the last GnRH injection.The ovarian response of the treated group clearly showed the organized events of follicular growth that ended by ovulation in one animal (33.3%), the changes in the small, medium, large and total follicle population and area did not differ significantly between the two groups.Luteinization of the dominant follicle following the first GnRH injection in two animals (66.6%) indicated the reliability of Ovsynch strategy to improve the ovarian function.The uterine response in the treated group was clearly improved as evidenced by an increase in the uterine wall Summary 99 homogenicity and decrease the uterine lumen (less than 0.3cm) and clearance of contents by Day 7-8 in the Ovsynchronized group.2. Expirment II : “Induction of ovulation during late postpartum period (late intervention)”2.1. Induction of ovulation during late postpartum period with prostaglandin F2α treatment : Animals in this expirment were assigned into : Group I : (n=49): “Synthetic prostaglandin F2α synchronized group” ; Animals in this group were treated with synthetic PGF2α; 500 μg of Cloprostenol.Group II : (n=40) “Natural prostaglandin F2α synchronized group” ; Animals in this group were treated with a natural PGF2α ; 25 mg dinoprost tromethamine.Group III: (n=47) “control group” ; Animals in this group were treated with saline at a dose and regime equivalent to the treated group.All animals during the synchronized period were observed every 12 hrs for the onset of estrus, rectally re-examined and were artificially inseminated thenafter.The use of synthetic PGF2α had a better synchronization results in buffalo-cows expressed in higher estrus response (79.59% vs. 70.00%), shorter synchronized period (4.47±2.17 vs. 5.68±0.81 days), and shorter Days open (71.23±1.55 vs. 86.5± 2.01 days) as compared with natural PGF2α treatement. On the other hand, both synthetic and natural PGF2α treatment associated with a good Synchronized pregnancy rate ; 55.10%and 55.00%, respectively, these was higher than control group (44.60%).Summary 100 2.2. Induction of ovulation during late postpartum period with longacting progesterone treatment : Animals under the present expirment were assigned randomly into Group I : (n=30) : “Single dose long acting progesterone synchronized group”; buffalo cows were given a single dose of 2 ml long acting
progesterone i.m.Group II: (n=7) “Double dose long acting progesterone synchronized group” ; buffalo cows were given 2 ml long acting progesterone i.m. in double dose, one week apart.single dose of long acting progesterone treatment asoociated with lower estrus response (53.00% vs. 71.42%), shorter synchronized period (6.91±0.64 vs.10.71±1.54 days), but longer Day open (138.26±6.76 vs.134.29±14.29 days) and lower synchronized pregnancy rate (36.67 % vs.57.14%) as compared with double dose of long acting progesterone.Comparing of animal response to induction of ovulation during late postpartum period with either prostaglandins PGF2α or long acting progesterone ; it was found that the use of PGF2α resulted in shorter Days open (127.40±4.60 vs. 138.26±6.76 days) and Synchronized period (5.10±0.20 vs. 6.91±0.14) and higher estrus response (64% vs. 53%), but lower pregnancy rate (31. 46 % vs. 36. 67 %) than the use of long acting progesterone.Summary 101 from the present study, it could be concluded that : 1. In spit of the lowered rate of ovarian response, the Ovsynch protocol is able to improve the ovarian and uterine function when applied during the early postpartum in buffaloes.2. The synthetic analogue of PGF2α seems to have a higher efficiency than the natural analogue of PGF2α in postpartum buffalo cows in terms of estrus synchronization and induction of ovulation.3. In accordance with the rate of response and the conception rate, synchronization of estrus by single injection of long acting progesterone is more effective and advisable in induction of estrus in buffalo-cows under the field condition.4. The use of PGF2α resulted in better estrus response, but lower pregnancy rate than the use of long acting progesterone in buffalo cows.References References 103 References Abdalla, E.B. (2003) >Improving the reproductive performance of Egyptian buffalo cows by changing the management system. Anim.Reprod.Sci.75: 1-8.Abd Al-Raheem, A. ; Eidaross, A. ; Mansour, H.A. (1988):<Trials for treatment of ovarian inactivity in cows and buffaloes.Alex.J.Vet.Sci. 4: 453-461.<Abdo, G.A. (1988) : Postpartum uterine infection in dairy cows, prevention and curative trearment. M.V.Sc. Thesis, Cairo Univ.Abeygunawardena, H. ; Abayawansa, W.D. ; Perera.