118 Superovulatory response and embryo production in beef cows treated with a recombinant human FSH

The aim of the present study was to evaluate the superovulatory response and in vivo embryo production in beef cows treated with a recombinant human FSH (r-hFSH, Nanopharma). Multiparous, nonlactating, cycling Brangus and Braford (Bos indicus influenced, n = 12) and Bonsmara and Angus (Bos taurus, n = 6) cows and with a body condition between 3 and 4 (scale 1–5) were randomly allocated into two treatment groups (r-hFSH or pFSH) and superovulated twice in a crossover design, to avoid individual animal variation. On Day 0, all donors received a progesterone-impregnated intravaginal device (Pluselar 1.2, Calier), along with 5 mg of oestradiol-17β (17β oestradiol) and 50 mg of injectable progesterone (Progesterona) intramuscularly (im). Superstimulatory treatments were initiated on Day 4 and the total dosage of r-hFSH or pFSH administered was based on the manufacturer’s recommendation for each biotype (Bos indicus: 300–500 IU, Bos taurus: 500 IU). For both groups, the treatments were carried out by dividing the total dosage in a decreasing way, divided into 8 injections given 12 h apart. All donors received 150 µg of D (+) Cloprostenol (Ciclar, Zoovet-Ceva) in the morning and afternoon of Day 6. On Day 7 in the afternoon the intravaginal device was removed, and all cows received 20 µg of buserelin acetate (Pluserelina, Calier) on Day 8 in the morning and were inseminated 12 and 24 h later with semen from bulls of proven fertility. Ova/embryos were collected on Day 15 and evaluated according to the IETS and the superovulatory response was evaluated by the number of follicles >9 mm in diameter on Day 8, and the number of corpus luteum (CL) and large (>10 mm) follicles on Day 15, determined by ultrasonography. Data were analysed using the GLMM procedure for a Poisson distribution. The fixed variable was treatment and breed. Cow (id) was a random effect. Although, the number CL and ova/embryos collected, fertilized ova and transferable embryos were greater for the donors treated with pFSH, the number of grade 1 embryos was not different among groups. Furthermore, the number of large follicles on Day 15 was greater in cows treated with r-FSH. There was no effect of breed or a breed by treatment interaction in any of the end points evaluated. In conclusion, p-FSH induced a greater superovulatory response and a tendency for more transferable embryos than r-hFSH. Nevertheless, r-hFSH was effective in inducing a superovulatory response in beef donors and these results warrant further investigation on dose titration.