Sire contribution to fertilization failure and early embryo survival in cattle.

摘要: Despite passing routine laboratory tests of semen quality, bulls used in artificial insemination (AI) exhibit a significant range field fertility. The objective this study was to determine whether subfertility AI is due issues sperm transport the site fertilization, fertilization failure, or failure early embryo conceptus development. In experiment 1, Holstein-Friesian (3 high fertility, HF, and 3 low LF) were selected from national population based on adjusted fertility scores minimum 500 inseminations (HF: +4.37% LF: -12.7%; mean = 0%). Superovulated beef heifers blocked estimated number follicles at time inseminated with HF LF (n 3-4 per bull; total 19 heifers). Following slaughter 7 d later, corpora lutea counted uteri flushed. Recovered structures (oocytes/embryos) classified according developmental stage stained 4',6-diamidino-2-phenylindole assess cells accessory sperm. Overall recovery rate (total recovered/total lutea) 52.6% not different between groups. Mean (± standard error mean) embryos recovered recipient 8.7 ± 5.2 9.4 5.5 for LF, respectively. However, more advanced stages development (all blastocyst combined), reflected greater cell versus bulls. Number derived than aim 2 evaluate effect sire survival bovine 15. Day blastocysts produced vitro using same 3) transferred groups 5-10 synchronized 42 Conceptus 15 higher (59.4%,) (45.0%). length conceptuses affected by status. conclusion, while differences among sires rate, quality apparent as 7. These likely contributed proportion surviving