Conception Rate in Dairy Cows Receiving a First or Repeatedly Used Controlled Internal Drug Release Devices in Timed Artificial Insemination Protocol

Abstract

Controlled internal drug release (CIDR) devices for releasing progesterone have been used for reproductive management in dairy cattle. In order to minimize the cost, the devices can be reused upon disinfection after being used for 7-8 days. Therefore, the aim of this research is to compare the conception rate of dairy cows after the first, second, and third-use of CIDR devices timed following artificial insemination (TAI) protocol. A total of 783 cows receiving short-term hormonal protocol (9.5 days) by inserting CIDR for 7 day. At the initiation of the TAI protocol, cows were randomly assigned into three groups, (1st CIDR; n = 312), (2nd CIDR; n = 233), and (3rd CIDR; n = 238). Moreover, in each CIDR group, cows were subdivided into two types (primiparous and multiparous cows). Cows in all groups were inseminated on day 9.5 of the TAI protocol. Diagnosis of pregnancy was performed using ultrasound on days 30 and 60 after insemination. From the results, the 1st, 2nd and 3rd used CIDR devices did not significantly change the conception rates on days 30 (28.8% vs. 25.3% vs. 28.2%, respectively) and 60 (26.9% vs. 24.5% vs. 27.7%, respectively) post-TAI in dairy cows (P > 0.05). The embryonic loss did not differ among cows receiving the 1st, 2nd and 3rd used CIDR devices (6.7% vs. 3.4% vs. 1.5%, respectively) (P > 0.05). For each CIDR group, parity (primiparous and multiparous) did not alter conception rates on days 30 and 60 post-TAI and embryonic loss in dairy cows (P > 0.05). Our findings indicate that the CIDR device could be used for at least three times in the TAI protocol in primiparous and multiparous dairy cows.