Resumen
- Multiparous Holstein cows were assigned in a randomized complete block design into four treatments from 21 d before calving to 30 d in milk (DIM). Treatments were: MET [n = 19, fed the basal diet + rumen-protected methionine at a rate of 0.08% (w/w) of the dry matter, Smartamine® M], CHO (n = 17, fed the basal diet + choline 60 g/d, Reashure®), MIX (n = 21, fed the basal diet + Smartamine® M at a rate of 0.08% (w/w) of the dry matter and 60 g/d Reashure®), and CON (n = 20, no supplementation, fed the close-up and fresh cow diets). Follicular development was monitored via ultrasound every 2 d starting at 7 DIM until ovulation (n = 37) or aspiration (n = 40) of the first postpartum dominant follicle (DF). Follicular fluid from 40 cows was aspirated and cells were retrieved immediately by centrifugation.