Table 1. Effect of origns of granulosa cells orign on oocyte growth.

GC addition	Day 16 Antrum formation	Oocyte ATP (pM)	24 h after IVF > 8 cell (Mean ± SE%)
–	56.2 ± 4.2 a	1.94 ± 0.12 a	12.0 ± 3.0 ab
Aged	69.4 ± 4.1 ab	2.21 ± 0.14 ab	5.0 ± 3.1 a
Young	73.3 ± 5.3 b	2.41 ± 0.10 b	25.0 ± 5.7 b

Oocyte and granulosa cell complexes (OGCs) collected from aged cows were cultured with or without additional granulosa cells (GC) for 16 days (Fig. 2), at which antrum formation was determined. GC were collected from OGCs of young or aged cows. In vitro grown oocytes were examined for their ATP content and developmental ability following in vitro maturation and fertilization.