Oral and Poster Abstracts

in each sample). On day 0, 104 cows were assigned to the following
treatments: 1) CIDR+ECP+P4 (n=24): one CIDR insert + i.m. 2 mg
of estradiol cypionate (ECP) and 100 mg of P 4; 2) CIDR+ECP
(n=22): a CIDR + 2 mg of ECP; 3) CIDR+EB+P4 (n=20): a CIDR +
i.m. 10 mg of estradiol benzoate (EB) and 100 mg of P 4; 4)
CIDR+EB (n=21): a CIDR + 10 mg of EB; 5) Control (n=17): i.m. 5
ml of saline solution as a placebo. The CIDR inserts were removed
on day 9. The CIDR-treated cows received timed artificial
insemination (TAI) 48 to 56 h after its removal, and the control cows
were AI 12 h after detected estrus. Detection of estrus was performed
twice daily from 24 h after CIDR removal until three days later.
Results: Pregnancy rate was 58.3% (14/24) for CIDR+ECP+P4,
63.6% (14/22) for CIDR+ECP, 45% (9/20) for CIDR+EB+P4,
47.6% (10/21) for CIDR+EB (P>0.05) and 17.6% (3/17) for the
control group (P