| dc.description.abstract | The objective of the present study was to compare two super stimulation protocols, which differ in dominant follicle removal (DFR) and gonadotropin-releasing hormone (GnRH), prior to ovum pick (OPU) in 45 Holstein-Friesian heifers in a field study which lasted eight weeks. Both protocols consist of a 14-day routine with one difference: DFR on the 10th day and GnRH treatment on the 9th day.
Results were evaluated for five groups (DFR/GnRH, synchronization (sync.)/once weekly OPU (non-sync.), young/old, # of the OPU session) on per sessions and week basis in antral follicle-, oocyte- and blastocysts count. Furthermore, the effect of high (≥2 ng/ml) /low (<2mg/ml) blood progesterone concentration (P4) at the beginning of the FSH (follicle stimulating hormone, FSH) stimulation was evaluated.
The results show that the GnRH protocol in comparison with the DFR scheme resulted in a, non-significant, improvement in all parameters (26,6 ± 16,6 – 24,4 ± 12,6 antral follicles (AF), 16,47 ± 19,2 – 11,7 ± 6,9 lab counted oocytes (oocytes) and 4,5 ± 4,2 – 3,4 ± 3,8 blastocysts, P>0,05). The sync. group showed, compared with the non-sync. group, an elevation of the same parameters (26,6 ± 15,6 – 20,6 ± 11,6 AF, 14,9 ± 15,3 – 10,2 ± 6,3 oocytes and 4,1 ± 4,1 – 3,2 ± 3,9 blastocysts, P > 0,05). Younger heifers showed the same elevation compared with older heifers (31,6 ± 19,7 – 21,7 ± 10,0 (AF), 18,3 ± 21,2 – 11,3 ± 6,0 oocytes and 4,5 ± 5,0 – 3,5 ± 3,3 blastocysts, P>0,05). No distinct time trend (OPU sessions) was discovered in any parameter during the experiment. High P4 levels, at the beginning of the FSH treatment, resulted in a non-significant elevation of the AF (27,9 ± 19,8 – 26,2 ± 11,5) and oocytes (17,0 ± 20,9 – 13,8 ± 10,1). Low P4 levels did result in a non-significant elevation of the blastocysts (4,2 ± 4,0 – 3,8 ± 4,1).
Concluding, this treatment did not harm the heifers in such way that the fertility was negatively influenced during this study. Likewise, this study shows that DFR is not superior to GnRH treatment in OPU/IVP efficiency. Moreover, a not significant detrimental effect was observed regarding the DFR treatment in every parameter. Besides, the P4 level at the beginning of the FSH treatment did not have any effect on all parameters. | |
