An estrus synchronization protocol (7-11 Synch) was developed to synchronize the first follicular wave and timing of ovulation in postpartum beef cows. In Exp. 1, follicular development and timing of ovulation in response to the following protocol were evaluated. Beef heifers (n = 12) and cows (n = 6), at random stages of the estrous cycle, were fed melengestrol acetate (MGA; .5 mg x animal(-1)...

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...

There have been several reproductive technologies developed over the past several years. Although these technologies have great potential to improve productivity of beef and dairy operations, they have only been minimally used. The reproductive technologies that may offer great value include estrus synchronization, embryo transfer, in vitro fertilization (IVF), sex-sorted semen, and embryo spli...

The objective of this study was to determine if factors associated with the biostimulatory effect of bulls alter breeding performance of primiparous, suckled beef cows using a progestin-based estrous synchronization protocol. We tested the hypotheses that the estrous synchronization response and AI pregnancy rates differ among cows exposed to bulls, continuously exposed to bull urine, and expos...

The objective of the experiment was to examine the necessity of adding a GnRH injection to a 14-d controlled internal drug release (CIDR)-based protocol for synchronization of estrus in beef heifers that were prepubertal or estrous-cycling at the initiation of treatment. The hypothesis tested was that the addition of GnRH in a CIDR-based estrus synchronization protocol would increase the synchr...

On d 0 of the experiment Bos indicus x Bos taurus (n=130) cows received an injection of GnRH and a progesterone-releasing device called an Eazi-BreedTM CIDR® for 7 d with a prostaglandin F2a injection at CIDR removal. Upon CIDR removal cows were divided into two AI treatments: 1) injection of estradiol cypionate (ECP) 24 h after CIDR removal with AI 8 to 10 h after a detected estrus and timed-A...

This trial evaluates reproductive performance in a early-routine estrus synchronization program using two different PGF2? . Cows were administered D(+)cloprostenol sodium (n=88; Group A) or dinoprost (n=78; Group B) between 35-42d postpartum. Pedometers were used to detect estrus. Evaluation of secondary signs of estrus and evaluation of vaginal mucus quality was made prior to AI. When estrus w...

Artificial insemination (AI) is an important technology for improving animal production. Through consistent use of AI, herd genetics can be advanced at a rapid rate. While AI is a technology that enables the dissemination of selected male genetics, embryo transfer (ET) is a technology that enables the dissemination of selected female genetics and, by using ET, frozen embryos can be moved around...