Offspring from Non-stimulated Calves at an Age Younger than Two Months: A Preliminary Report

Abstract

Abstract. This study investigated the viability of embryos from non-stimulated 2-3-month-old calves generated in vitro using oocytes from follicles of defined size in terms of their ability to produce fullterm pregnancies. Ablation of follicles ≥4 mm was used to induce the emergence of a new follicular wave, and calves (n=3) were laparoscopically punctured three times at 7-day-intervals to recover cumulus-oocyte-complexes (COCs) from follicles >8 (group A) and between 4-8 mm (group B). Calves were aged 49, 56, and 80 days, respectively, at first recovery. Morphologically intact COCs were subjected to in vitro maturation, fertilization, and embryo culture, and compact morulae/ blastocysts were transferred on day 7 post-insemination to synchronized virgin heifers. Blood typing was used for maternity analysis. A total of 29 COCs were recovered, 21 cultured, yielding 11 cleaved embryos (52.4%) and 6 compact morulae/blastocysts (28.6%). No differences were observed between groups. Transfer of the 6 embryos to 5 recipients resulted in three pregnancies (one from group A and two from group B). Two normal male offspring (both from group B), with birth weights of 44 and 51 kg, were born, and two donor calves, aged 56 and 59 days, were identified as the dams. In conclusion, the results demonstrate that embryos generated in vitro from oocytes from non-stimulated calves at an age younger than two months are viable in terms of their ability to produce full-term pregnancies, and suggest that the viability of calf embryos is not related to follicle size.

Laparoscopic ovum pick-up for in vitro embryo production from dairy bovine and buffalo calves

“…Development to the blastocyst stage was affected by gonadotropin treatment, with higher rates obtained for longer compared with shorter protocols, as well as for protocols combining FSH and eCG compared with FSH alone. This is consistent with previous studies in older animals (Hendriksen et al, 2000;Machatkova et al, 2004) and non-stimulated bovine calves (Kauffold et al, 2005a), where oocytes collected from larger follicles were capable of higher rates of development to blastocyst.…”

Laparoscopic Ovum Pick-Up Followed by In Vitro Embryo Production and Transfer in Assisted Breeding Programs for Ruminants

“…In our work with prepubertal dairy cattle and buffalo, we used standard commercial bovine media and procedures with minor deviations from those previously published [57]. This is consistent with publications by others, who also showed little to no deviation in the media and procedures used for IVM/F/C of calf oocytes compared with those in use for adult cows and mature heifers [26,30,[58][59][60][61]. One deviation was the addition of antioxidants to the maturation medium in buffalos, which has been shown to be of great importance given the high lipid content of buffalo oocytes, making them more susceptible to peroxidation damage [62].…”

In Vitro Production of Embryos from Prepubertal Holstein Cattle and Mediterranean Water Buffalo: Problems, Progress and Potential

“…Consequently, prepubertal donors typically produce more COCs and 2-cell stage embryos than adult donors. Blastocysts derived from prepubertal oocytes are competent to support full-term development and normal offspring have been produced in multiple species, including buffalo [ 7 , 27 ] and cattle [ 23 , 53 , 54 ]. Hence, the primary challenge remains the improvement of oocyte competence to enable higher embryo development rates to the blastocyst stage.…”