the aim of this study was to compare the efficiency of five synchronization protocols, economically, in holstein cows during heat stress. this experiment was conducted at a commercial dairy farm in summer 2015 (temperature humidity index 73–81). five hundred holstein dairy cows with ˃25 kg/d milk yield were randomly assigned to five experimental groups: 1) ovsynch; 2) presynch-ovsynch; 3) doubl...

Background: To design a pre-Ovsynch hormonal strategy in yaks in order to increase the ovulatory response to the first GnRH injection of Ovsynch so that overall synchronization rate to Ovsynch could be improved. Materials and Methods: Non-lactating cyclic yak cows (n=33) were assigned to receive either no treatment before Ovsynch (control) or 0.375mg of PGF2(PreP) followed 2 d later by 10 g of ...

The objective was to evaluate whether addition of EAZI-BREED CIDR Cattle Inserts (CIDR) to the Ovsynch program increases first service pregnancy rate (PR) in lactating dairy cows. The study was conducted in 5 dairies in Central Mexico. Cows were inseminated from June through September, 2001. Within trial site and within parity, cows were assigned to either an Ovsynch (n=255) or an Ovsynch-CIDR ...

We compared synchronization and pregnancy rates, and the increase in blood progesterone concentrations during luteal development, between (1) Ovsynch plus an intravaginal controlled internal drug release (CIDR) device protocol followed by timed embryo transfer (timed ET), and (2) a conventional estrus synchronization method using PGF(2 alpha) and ET in suckled postpartum Japanese Black beef cow...

Background: Presynchronization could enhance fertility in timed breeding programs. The best presynchronization method has to justify biological requirements and to provide practical and economic advantages. OBJECTIVES: Present study investigated the effectiveness of presynchronization with equine chorionic gonadotropin (eCG) before ovsynch (eCG-ovsynch) compared to conventional presynch-ovsynch...

Pregnancy rates were compared in lactating dairy cows (n = 1083) assigned to protocols for resynchronization of ovulation based on stages of the estrous cycle, or presence of ovarian cysts or anestrus. Cows were detected not pregnant by ultrasonography 30 d after a previous AI (study day 0) and classified as diestrus, metestrus, proestrus, with ovarian cysts or anestrus. Cows in diestrus (Janua...

OBJECTIVE The aim of this study was to monitor the ovarian response and conception rate following estrous synchronization using CIDR, Ovsynch and double prostaglandin F2α protocols in Egyptian buffalo heifers. MATERIAL AND METHODS A total of 80 cyclic buffalo heifers were divided into four equal groups: CIDR (intravaginal progesterone releasing device, EAZI-BREEDTM CIDR®), Ovsynch (GnRH, PGF2...

The present study was designed to evaluate the effect of Ovsynch protocol in repeat breeding crossbred Jersey cows. A total of thirty four repeat breeding cross bred Jersey cows were subjected to Ovsynch protocol with timed artificial insemination. The pregnancy rate in Ovsynch protocol was 58.82 per cent where as it was 29.41 per cent in control group. Thus, the Ovsynch protocol can be effecti...

This study evaluated the effect of resynchronization programs on pregnancies in dairy cows. Of 1,342 cows confirmed not pregnant after their first artificial insemination (AI), those with a corpus luteum (CL) were resynchronized using Ovsynch or PG-GnRH-Ovsynch and without CL GnRH-Ovsynch modified Double-Ovsynch. There no differences (p > 0.05) per AI either between (31.3%) (34.0%) (38.7%) D...