The CIDR is an intravaginal progesterone insert, used in conjunction with other hormones to synchronize estrous in beef and dairy cows and heifers. The CIDR was developed in New Zealand and has been used for several years to advance the first pubertal estrus in heifers and the first postpartum estrus in cows. The CIDR is a “T” shaped device with flexible wings that collapse to form a rod that c...

38 Lactating dairy cows (n=1,538) were enrolled in a randomized complete block 39 design study to evaluate protocols to synchronize estrus and ovulation. Within each 40 herd (n=8), cows were divided into three calving groups: EARLY, MID and LATE 41 based on days in milk (DIM) at mating start date (MSD). EARLY calving cows 42 (n=1,244) were  42 DIM at MSD, MID calving cows (n=179) were 21 to 41...

Our model of the bovine estrous cycle is a set of ordinary differential equations which generates hormone profiles of successive estrous cycles with several follicular waves per cycle. It describes the growth and decay of the follicles and the corpus luteum, as well as the change of the key substances over time. In this work we describe recent improvements of this model, including the introduct...

Expanded use of artificial insemination (AI) and/or adoption of emerging reproductive technologies for beef heifers and cows require precise methods of estrous-cycle control. New protocols for inducing and synchronizing a fertile estrus in replacement beef heifers and postpartum beef cows in which progestins are used provide new opportunities for beef producers to synchronize estrus and ovulati...

Background: Acute-phase proteins (APPs) may be increased due to different stresses during estrus phase in farm animals. Aims: Determining changes of APPs at different phases of non-synchronized estrous cycle group (NSEG), and Ovsynch-synchronized estrous cycle group (SEG) in Holstein cows. Methods: Twelve non-pregnant clinically and paraclinicaly healthy Holstein cows with a body condition scor...

two experiments were performed to determine the effectiveness of different progestogens contained in intravaginal devices, different doses of ecg and subsequent hcg treatment on the reproductive performance of estrus-induced mature lori ewes. in the first experiment, 88 ewes were allocated into two groups, and were treated with either fluorogestone acetate (fga) sponges or controlled internal d...