| The objectives of these investigations which were all directed toward resynchronization of estrus were to evaluate: (i) the use of a milk progesterone (P4) test on day 21 post-insemination (AI) following an Ovsynch synchronization protocol with timed-AI to identify pregnant dairy cattle; (ii) resynchronization of non-pregnant dairy cows on day 14, prior to pregnancy diagnosis, using the Ovsynch protocol with timed-AI to accelerate re-breeding and increase pregnancy rate within a 35 day period and (iii) to evaluate the CIDR as a supplemental P4 source on days 11 through 18 post-AI, following a prior CIDR administration to synchronize estrus, to increase pregnancy rates of the initial and subsequent AI during heat stress and non-heat stress conditions. To examine objectives i and ii, three studies were conducted: a preliminary late Spring study conducted in 2001 with repeat breeders and two early Spring studies conducted in Spring 2004 and 2005. (Abstract shortened by UMI.)... |
