Evaluation of intravaginal progesterone device, in until three uses, in fixed-time artificial insemination in “Bos indicus” females

Abstract

The objective was to evaluate the effect of the number of utilizations of CIDR, estrus manifestation and bearing order on the pregnancy rate in Bos indicus. We used in 1176 lactating multiparous and primiparous cows, 30 to 60 days post-partum. The groups received first, second- or third- use CIDR, plus 2,0mg of estradiol benzoate (EB) when the device was introduced (D0), and 500 μg of dinoprost trometamin, 300 UI of eCG and 0,6 mg of estradiol cypionate at the device withdrawal (D8), with FTAI 48 hours after (D10). At 30 days realized the pregnancy diagnosis (D40). The variables were analyzed by PROC LOGISTIC (SAS) and binary logistic regression, and the difference was statistically significant when p<0.05. The amount of implant uses influenced the pregnancy rate (1 use < 2 uses – p < 0.05; 1 use < 3 uses – p<0.01; 2 uses = 3 uses; p>0.1); of 44.8%, 51.1% and 51.1% for CIDR 1, 2 and 3 uses, respectively; as bearing order (multiparous 50.85% > primiparous 34.48%; p<0.01) and estrus manifestation (estrus 44.02% > no estrus 33.06%; p<0.01). CIDR can be utilized up to three times, but the pregnancy rate showed lower for the first-use in relation to second and third uses and biggest results in multiparous and with estrus manifestation.