CIDR Inserts:
Controlled internal drug release (CIDR®) inserts, first produced in 1981 in New Zealand, now used internationally, and is currently being sold in 24 countries, such as Canada and Japan. (Wheaton et al., 1993; Greening & Hafs, 2001). These inserts are used for numerous livestock, including beef cattle, dairy cattle, sheep and goats (Bó & Baruselli, 2014; Rudolph et al., 2011; Wheaton et al., 1993). CIDR ® devices are composed of the natural hormone progesterone (C21H30O2) (CIDR® 1380, 2016). Veterinarians, as well as farmers, tend to favour this veterinary product as they are dependable hormone release process and can be repeatedly used (Macmillan & Peterson, 1993). The inserts are entrapped by and molded with a silicone layer, with an attached flexible nylon spine. (CIDR® 1380, 2016).
CIDR ® 1380 and CIDR ® 330:
Produced in Canada, CIDR ®1380 (Figure 1) and CIDR® 330, designed for cattle and sheep, respectively, are two varieties of CIDR® inserts (CIDR® 1380 2016; CIDR®330). Both are composed of progesterone, but vary in the amount; CIDR ® 1380 contains 1.38 grams, while CIDR ® 330 0. 35 grams of progesterone. (CIDR® 1380, 2016). Although the masses of progesterone differ, both have similar impacts in its designated species. They allow for greater control over reproductive cycles in both cattle and sheep, through synchronization of estrus cycles as well activating estrus cycles (Robinson, 2016).
CIDR ® 1380:
Designed for lactating, suckled, or replacement cattle, whether beef or dairy (CIDR ® 1380, 2016). Within bovines, CIDR ® inserts have been found to increase both conception rate and embryo survival (El-Zarkouny et al., 2004). Additionally, through the study of the response of a Korean cattle herd to these inserts, it was determined that the supplements cause an increase in ovulation response, superovulation (Son et al., 2007; Robinson, 2016).CIDR ® are sold both individual or in packages containing ten inserts, with a price of around $20.00 and $208.70 respectively (Dundas Animal Hospital (DAH), 2016; Robinson, 2016).
CIDR ® 330:
CIDR ® 330 (Figure 2) inserts are designed for ewes, female sheep. (CIDR®330, 2016). The majority of a group of ewes, treated with simultaneously gave birth within six days of each other (Wheaton et al., 1993). While a flock of sheep, not treated with controlled internal drug release devices, lambed within a sixteen day period of each other. (Wheaton et al., 1993). Similar to 1380, these inserts are sold both individual, $6.70, or in a package; however, the package contains twenty inserts, $142.70 (DAH, 2016).