interesting, to me at least

[themarchcat]

During my AI class at school, we were picking through a research paper that is discussing the use of CIDRs in estrous synchronization systems (in cattle) and that spiked the interest of my teacher and he then in turn questioned us about the use of CIDRs (are they called that for horses?) in horses. Now I do not know anything about CIDRs (?) in horses as I have not researched the topic and all we get to work on/with at school are cattle, so my questions might be stupid, but I’m very curious and trying to learn. =)

Are they used in horses? If so, what industry are they mainly found to be used in? What’s the reasoning in that? Are they as effective in horses as they are in cattle? In cattle, CIDRs are used on a really widespread scale and sometimes a single CIDR is used twice in a second cow if need be. They are great tools to help regulate a cow’s/heifer’s cycle, but are they as practical in horses as they are in cattle?

Those are the only questions I can think of at this moment. Feel free to answer as best as you can, I’m very interested to see what you all say. I’ll be doing some research of my own until I hear some response. =)

[Hillside_H_Ranch]

Technically you can use them in mares (they do work) but they cause an extremely severe (and somewhat disgusting ) vaginitis that most people don’t want to deal with.

[themarchcat]

Really? No one else has helpful information? =/

[skippy60]

Ok I don’t want to sound stupid… but what’s a CIDR?

[themarchcat]

A CIDR is a vaginal insert for cattle (smaller versions used on sheep, goats, etc) to supply them with progesterone to inhibit the estrous cycle until the entire herd is “synced”, which the CIDR will then be removed and then a shot of PGF2alpha will be given to jump start the cycle.

https://animalhealth.pfizer.com/sites/pahweb/US/EN/Products/Pages/Eazi-Breed_CIDR.aspx

They are shaped like a T and press against the inner wall of the vagina to avoid slipping around inside or coming out until pulled out (by the string).

[Anne]

I was taught that CIDRs don’t work in horses, but I don’t remember why. (It’s entirely possible that my educators meant the vaginitis issue.)

Mass synchronization of a large group of mares is usually not necessary the way it is in cattle.

[themarchcat]

Yeah see that was what I was thinking, but I kept my thoughts to myself because we have a know-it-all that’s supposedly a “horse breeder” that was saying it’s very common to snyc mares, especially in the racing industry (TB or QH). Now I can believe that to an extent, but I really don’t think it’s that useful or prevalent in horses, not as much as she was saying. I am hoping to get some “hard facts” to share in the class tomorrow.

[cyriz_s_mom]

Well mares can be sync’d especially for ETs using P&E…just not the insert (which sounds kinda like an IUD but with a different purpose).

[themarchcat]

=) I don’t doubt that they can be synced, I just didn’t feel like it was done with any vaginal insert. What are they called in horses? Are they this IUD you mentioned?

[Equine_Reproduction]

Although CIDR’s (Controlled Intravaginal Drug Release devices, also referred to as PRID’s or Progesterone Releasing Intravaginal Devices) are widely used in the bovine industry in North America, they are not in the equine. This is not because they do not work, but due to a lack of availability of the correct device, as there is no FDA-approved CIDR for the equine although the bovine version marketed as the “Eazi-breed” has been used in an off-label manner.

CIDR’s releasing progesterone are used in the southern hemisphere and the UK, and in fact one specifically designed for use in the equine was developed in New Zealand - the “Cue-Mare”. This model overcomes some of the issues associated with the bovine version being used in the equine, where accidental loss of the device is common.

It should be noted that while CIDR/PRID use in the equine has been demonstrated to have a similar effect to the use of Regumate or other progestins, there is a transient vaginitis associated with it’s use. This does typically clear however by the time the mare enters estrus and breeding commences. While the timing of onset of estrus in the cycling mare is similar to that seen following treatment with Regumate, the same issues apply regarding failures. In an attempt to reduce the potential for these failures, the addition of estrogens to the treatment profile (to create a sort of P&E effect) has been attempted, but although this improved the timing of the onset of the subsequent estrus, it did not “pinpoint” the ovulation to the same degree as is seen with P&E or biorelease altrenogest.

We present the following observations in our course notes:

• CIDR (Controlled Intravaginal Drug Release) devices, aka PRID (progesterone releasing intravaginal device) (Eazi-Breed CIDR Cattle Insert, Pharmacia Animal Health, Kalamazoo MI; Cue-Mare, Duirs PfarmAg, Hamilton NZ) have been demonstrated to assist in hastening the onset of first ovulation (Newcombe JR, Wilsom MC: The use of progesterone releasing intravaginal devices to induce seasonally anœstrus Standardbred mares in Australia. Equine Prac. 1997; 19:13-21)
• This treatment may be combined with an ovulatory stimulant such as Deslorelin or hCG (Newcombe JR, Handler J, Klug E et al: Treatment of transition phase mares with progesterone intravaginally and with deslorelin or hCG to assist ovulations. J. Equine Vet. Sci. 2002; 22:57-64)
• Transient vaginitis and cervicitis is to be expected, although this usually resolves by the time of breeding;
• With mares that respond, rapid onset of œstrus and ovulation within 4-8 days of the removal of the device is to be anticipated;
• Pregnancy rate may be decreased in mares that ovulate >6 days after removal of the CIDR;
• Up to 5% of mares may be expected to expel the device, although the design of the Cue-Mare has largely overcome this problem.

Some additional research is available for viewing in the following paper: Handler J, Schönlieb S, Hoppen H-O, Aurich C.: (2007) Influence of reproductive stage at PRID™ insertion on synchronization of estrus and ovulation in mares; Animal Repro Science 97:3-4; 382-393

Hope this helps.

[themarchcat]

Thank you so much Kathy! I will be printing that paper out to give to my professor!