In vitro embryo production using ovaries removed from culled cows

Abstract

The objective was to utilize in vitro maturation and fertilization to maximize embryo production from culled dairy cows. Ovaries were removed (via a colopotomy technique) from culled Holstein cows (n = 21) 2 d after standing estrus (T1), 2 d after treatment with 40 mg follicle stimulating hormone (FSH) given at standing estrus (T2), or at an unknown stage of the estrous cycle (T3).Treatment with FSH increased (P < 0.05) oocyte recovery rate (mean ± SEM, 14.6 ± 2.2, 25.4 ± 3.4, and 11.1 ± 2.6 oocytes ovary–1), for groups T1, T2 and T3, respectively, and the number of blastocysts obtained (1.6 ± 0.5, 4.4 ± 0.4 and 1.6 ± 0.6 blastocysts ovary–1). Culled dairy cows of high genetic merit are potential embryo donors, with an average of six to eight transferable embryos obtained from each FSH-treated cow. Key words: FSH treatment, oocyte recovery, IVM, IVF, culled cows