If you use a controlled-internal-drug-releasing (cidr) device to help get heifers bred, make sure that you stick to the recommended schedule. If it is day 15 in a heifer’s cycle, and you insert a CIDR, that follicle remains viable, Carlos Risco, professor of food animal reproduction and medicine at the University of Florida, told attendees at the Western Veterinary Conference. The CIDR slows the growth of the follicle and must be removed at day seven or eight. If you leave it in too long, the result is a cystic follicle as opposed to a good breedable follicle.