Estrus expression rate differed between the 5-day COSynch
þ CIDR and the 7-day CO-Synch þ CIDR groups (P
< 0.0001), among days postpartum categories (P < 0.01),
and BCS categories (P < 0.05; Fig. 2). A greater proportion of
cows in the 7-day CO-Synch þ CIDR group expressed estrus
compared with cows in the 5-day CO-Synch þ CIDR group,
61.1% (554/906) versus 52.9% (482/911), respectively