Effect of follicle ablation before ovum pick-up in Girolando cattle

The present study characterized the effect of follicle ablation (FA) intervals on the follicular population and the quantity and quality of cumulus-oocyte complexes (COCs) from 1/2 and 1/4 Girolando donors (n=125 and n=110, respectively) at Ovum Pick-Up (OPU). The timing for that FA has not been definitively established. Our hypothesis was that FA in 1/2 and 1/4 blood Girolando donors performed 48 hours prior to OPU provided more and higher quality COCs than at 72 hours post-FA. To test this hypothesis, FA performed 48 h or 72 h before OPU, and the ovarian follicular population (grouped by size) and quality (grade I-IV) of COCs recovered from OPU were evaluated. The FA 48 h and 72 h groups had a greater estimated number of medium-sized follicles (more developed) compared with the control group without FA (18.39±1.42, 14.98±1.42, and 10.84±1.42 follicles, respectively, P<0.01) at OPU. Furthermore, there was a greater number of highest-quality COCs at FA 48 h than at FA 72 h and control (2.09±0.31, P= 0.004, 1.11±0.31, and 0.92±0.31 COCs, respectively). In comparison, 1/2 Girolando had greater counts of medium (18.3±2.02, P=0.05) and total follicles (33.34±2.67, P=0.02) and grade IV COC (5.52±0.64, P<0.01) than 1/4 Girolando (11.35±2.02, 22.56±2.67, 0.77±0.64, respectively). The association of FA with OPU on 1/2 and 1/4 Girolando has advantageous effects, resulting in the aspiration of more developed follicles and better-quality oocytes. Besides that, 1/2 Girolando has a greater follicular count than 1/4 Girolando, although these crosses respond similarly to FA. Overall, FA improves OPU outcomes.