Use of sex-sorted and unsorted frozen/thawed sperm and in vitro fertilization events in bovine oocytes derived from ultrasound-guided aspiration

Abstract

The objective was to investigate the effects of sex-sorting on early fertilization events in ovum pick up (OPU) derived oocytes fertilized in vitro with frozen-thawed sperm at different co-incubation lengths. Eighty-four OPU sessions were carried out in 18 cyclic, dry and non-stimulated Holstein Friesian and German black pied cows. Ovum pick up oocytes were matured in vitro for 24 hours and fertilized with frozen-thawed sex sorted or unsorted sperm from the same ejaculate. Fertilization was achieved by two experimental protocols: 1) short gamete co-incubation length: 4, 8 and 12 hours; and 2) long gamete co-incubation length: 18 and 24 hours. After in vitro fertilization, ova were fixed and stained to identify early fertilization events. Sperm penetration, monospermy, pronuclear formation and syngamy did not differ, whether sexed or unsexed sperm was used. Overall, the findings demonstrate similar fertilizing potential between sex-sorted and unsorted sperm.

Pregnancy and offspring sex ratio following insemination with SexedULTRA and conventional semen in cows in a commercial beef operation

“…Early embryonic demise after fertilization with SS (x-sorted) both in in vivo and in vitro has been reported (Steele et al, 2020). In contrast, some studies showed that similar cleavage and blastocyst rate for embryos were generated from sexed (x-sorted) and non-sexed sperm (Carvalho et al, 2010;Ruiz López et al, 2003;Xu et al, 2009). Further, overall calving rate following transfer of in vitro produced embryos with non-sorted or x-sorted sperm has been shown to be similar (Carvalho et al, 2010;Rasmussen et al, 2013).…”