Controlled internal drug release

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Controlled internal drug release (CIDR) devices are used in livestock for the synchronization of estrus. They are T-shaped devices with a silicone-coated nylon core.[1] The silicone coating is impregnated with progesterone.[2] CIDRs are inserted intra-vaginally using a specialized applicator. The flexible wings collapse for facilitated insertion and expand once placed appropriately within the vagina.[2] The expansion of the wings retains its position; CIDRs have very high retention rates that may exceed 97%.[3] A thin nylon tail remains exteriorized and is used for removal.[2]

Once inserted, CIDRs provide slow-release administration of progesterone, which artificially extends the luteal phase.[1] Plasma progesterone levels rapidly increase upon insertion, and remain relatively consistent while in place.[4] Following CIDR removal, progesterone levels decrease rapidly.[3] Occasionally, vaginal irritation may occur. This is normal and does not impact the effectiveness of the device or the animal’s performance.[3]


There are several types of CIDRs available, including CIDR-B for cattle, CIDR-S for sheep and CIDR-G for goats. CIDRs are similar to the progesterone-releasing intravaginal device (PRID), also used for synchronization of estrous cycles in livestock.

History[edit]

CIDRs were developed by AHI Plastic Moulding Company in Hamilton, New Zealand, in conjunction with the Ministry of Agriculture and Forestry (New Zealand).[4] Developmental trials began in 1981. The CIDR-S was licensed in 1986 and the CIDR-G in 1988.

CIDR Use[edit]

CIDRs are approved for use in both beef cattle and dairy heifers in Canada and the United States.[2] CIDRs contain 1.9g of progesterone in Canada and 1.38g in the United States.[2] The CIDR-S is licensed for use in sheep and goats in New Zealand and Australia.[1] The CIDR-G is also suitable for use in ewes, lambs and goats.[4]

In cattle, CIDR-Bs are often used with synchronization protocols. The product label typically indicates that, in conjunction with an appropriate synchronization protocol, CIDRs should be left in for 7 days.[2] Ovsynch is a particular protocol that is often followed.[5] These estrus synchronization protocols allow Fixed Time Artificial Insemination to be used, giving herd managers more accurate control.[6] The use of CIDRs with synchronization protocols helps improve reproductive performance by reducing the inefficiency associated with estrus detection.[6]

Although there is variability in the response to estrus synchronization, studies show consistently high pregnancy rates following Fixed Time Artificial Insemination with CIDR synchronization of ovarian follicle development.[2]

Therapeutic Use[edit]

CIDRs may be used as a treatment in cows with follicular cysts. Follicular cysts in cattle affect a significant proportion of dairy cows in several countries, and hinder the dairy industry by extending the period from calving to conception.[7] CIDRs help by reducing the Luteinizing Hormone pulse frequency and inducing atresia of cystic follicles.[7] This may also allow affected cows to be re-used in breeding or embryo transfer programs.

Sheep and Goats[edit]

Previously, intravaginal progestogen sponges were a common method of estrus manipulation in ewes.[8] The development and success of CIDRs has increased their use in sheep and goats. Unlike intravaginal progestogen sponges, CIDRs do not absorb or impede drainage of natural vaginal secretions, offering a cleaner method of delivery.[1][4] They also allow administration of a natural form of hormone, as opposed to the potent analogues used in sponges.[4] A dose of 550 mg of progesterone has been found to be effective in controlling estrus and ovulation in sheep.[8]

References[edit]

  1. ^ a b c d Carlson, K.M.; Pohl, H.A.; Marcek, J.M.; Muser, R.K.; Wheaton, J.E. (1989). "Evaluation of progesterone controlled internal drug release dispensers for synchronization of estrus in sheep". Animal Reproduction Science. 18 (1–3): 205–218. doi:10.1016/0378-4320(89)90022-5. 
  2. ^ a b c d e f g Mapletoft, J.R; Martínez, M.F.; Colazo, M.G.; Kastelic, J.P. (2003). "The use of controlled internal drug release devices for the regulation of bovine reproduction". Journal of Animal Science. 81 (14): E28–E36. 
  3. ^ a b c Eric Grant. 2006. Understanding CIDR. National Association of Animal Breeders. Feb 1, 2006. Retrieved March 20, 2012, from Beef Magazine: http://beefmagazine.com/mag/beef_understanding_cidr
  4. ^ a b c d e Wheaton, J.E; Carlson, K.M.; Windels, H.F.; Johnston, L.J. (1993). "CIDR: A new progesterone-releasing intravaginal device for induction of estrus and cycle control in sheep and goats". Animal Reproduction Science. 33 (1–4): 127–141. doi:10.1016/0378-4320(93)90111-4. 
  5. ^ Pursley, J. R.; Wiltbank, M.C.; Stevenson, J. S.; Ottobre, J.S.; Garverick, H.A.; Anderson, L.L. (1997). "Pregnancy rates per artificial insemination for cows and heifers inseminated at a synchronized ovulation or synchronized estrus". J. Dairy Sci. 80: 295–300. doi:10.3168/jds.s0022-0302(97)75937-x. 
  6. ^ a b Chebel, R.C.; Al-Hassan, M.J.; Fricke, P.M.; Santos, J.E.P.; Lima, J.R.; Martel, C.A.; Stevenson, J.S.; Garcia, R.; Ax, R.L. (2010). "Supplementation of progesterone via controlled internal drug release inserts during ovulation synchronization protocols in lactating dairy cows". Journal of Dairy Science. 93 (3): 922–931. doi:10.3168/jds.2009-2301. 
  7. ^ a b Todoroki, J.; Kaneko, H. (2006). "Formation of Follicular Cysts in Cattle and Therapeutic Effects of Controlled Internal Drug Release". Journal of Reproduction and Development. 52 (1): 1–11. doi:10.1262/jrd.17081. 
  8. ^ a b Ainsworth, L.; Downey, B.R. (1986). "A controlled internal drug-release dispenser containing progesterone for control of the estrous cycle of ewes". Theriogenology. 26: 847–856. doi:10.1016/0093-691x(86)90014-2. 

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