Effect of follicle wave synchronization and gonadotropin treatments on the number and quality of cumulus-oocyte complex obtained by ultrasound-guided ovum pick-up in beef cattle
Ongaratto, F. LRodriguez-Villamil, PTribulo, ABó, G. A
Four experiments were designed to evaluate the effect of different hormonal treatments on the number and quality of cumulus oocyte complexes (COCs) recovered by ovum pick-up (OPU) in beef cattle. Experiment 1 compared the synchronization of follicle wave emergence with 2 mg estradiol benzoate (EB) and 50 mg progesterone (P4) given intramuscularly (i.m.) 6 days before OPU versus a control group in which donors did not receive any treatment. Experiment 2 evaluated the use of equine chorionic gonadotropin (eCG) and prostaglandin F2α prior to OPU. Experiment 3 compared the effect of dominant follicle removal (DFR) by ultrasound guided follicle aspiration or EB+P4 to control follicular wave emergence, and treatment with eCG or FSH to superstimulate follicle growth. Experiment 4 evaluated the effect of inserting a progesterone releasing device (CIDR) during the superstimulation treatment. In experiment 1, treatment with EB+P4 resulted in more (P < 0.05) viable COCs (5.2 ± 0.9 vs. 2.1 ± 0.4) than the controls. In experiment 2, prostaglandin F2α prior to OPU increased (P < 0.05) the number of viable COCs (7.9 ± 1.1), but treatment with eCG did not affect (P > 0.1) the number of COCs (4.5 ± 1.0) recovered compared to the controls (4.7± 0.7). In experiment 3, there were no differences (P > 0.1) between DFR and EB+P4; however, treatment with FSH resulted in more (P < 0.05) COCs recovered than eCG (6.8 ± 0.6 vs. 3.7 ± 0.6). In experiment 4, insertion of a CIDR device did not affect the number of COCsrecovered compared to the controls (6.3 ± 0.7 vs. 5.8 ± 0.7,respectively). In conclusion, the use of treatments that synchronize follicle wave emergence, prostaglandin F2a to avoid the presence CL at the time of OPU and superstimulation with FSH were useful to improve the number of COCs recovered in beef cattle. Conversely, the insertion of a CIDR device during the superstimulation treatment prior to OPU did not improve the number of COCs recovered nor their quality.(AU)
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