title: The efficiency of new CIDR and once-used CIDR to synchronize ovulation in primiparous and multiparous Holstein cows.
abstract: The objective of this study was to elucidate the efficiency of Ovsynch protocol, new (N-CIDRsynch) and once-used (U-CIDRsynch) controlled internal drug-release (CIDR) devices to synchronize the ovulation time of primiparous and multiparous Holstein cows. The current study was performed on a total of 2207 cows using three different synchronized groups. Conception [pregnancy per AI (P/AI) at day 28] and pregnancy (P/AI at day 75) rates using the N-CIDRsynch and U-CIDRsynch regimens (35.9% and 29.6%; 29.2% and 25.1%, respectively) were significantly greater than those in the Ovsynch group [Odds ratio (OR)=1.88 and 1.44; 1.92 and 1.52, respectively]. Embryonic loss rate did not differ significantly (P>0.05) among the Ovsynch, N-CIDRsynch and U-CIDRsynch regimens. In primiparous cows, no significant differences were found in conception and pregnancy rates between the U-CIDRsynch and N-CIDRsynch groups (OR=0.95 and 1.12; p=0.693 and 0.451, respectively). In multiparous cows, conception and pregnancy rates in the N-CIDRsynch group were significantly greater than those observed in the U-CIDRsynch group (OR=0.66 and 0.71; p=0.016 and 0.027, respectively) and embryonic loss rate in multiparous cows was lower for the U-CIDRsynch treatment than for the N-CIDRsynch treated cows (COR=0.58; p=0.048). The present study indicates that the use of a progesterone device in a synchronization protocol may improve fertility in dairy cows compared to the Ovsynch treatment. The use of U-CIDRsynch regimen may achieve satisfactory fertility results compared to those reported with N-CIDRsynch in primiparous Holstein cows.
authors.affiliation: Department of Animal Wealth Development, Faculty of Veterinary Medicine, Zagazig University, Sharkia, El-Zeraa str. 114, 44511-Zagazig, Egypt. Electronic address: mahmoudtarabany2887@yahoo.com.
authors.forename: Mahmoud S
authors.initials: MS
authors.lastname: El-Tarabany
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D003692:Delayed-Action Preparations; D004305:Dose-Response Relationship, Drug; D004973:Estrus Synchronization; D005260:Female; D007315:Insemination, Artificial / Q000662:veterinary; D010060:Ovulation / Q000187:drug effects; D010062:Ovulation Induction / Q000662:veterinary; D011247:Pregnancy; D018873:Pregnancy Rate; D011374:Progesterone
chemical_list: D003692:Delayed-Action Preparations; D011374:Progesterone
keywords: CIDR; Fertility; Holstein; Parity; Synchronization