Summer Breeding - Fast Cycling?

[jdeboer01]

I’m wondering if anyone using P&E, with Lutalyse on day 10, has found the mare has already ovulated on day 18? Last season a had a mare (not using P&E) who was cycling every 17 days. Needless to say, I missed her twice. Will using P&E prevent this? Or should I possibly wait a day to give the lutalyse just in case? I’m trying to put her on MY schedule for a stallion that collects only M-W-F, and I’d like to time her to be bred on a Tuesday from a Monday collection, but I’m afraid she may go and ovulate early on me!

Also, would giving lutalyse on day 11 or 12 (as opposed to day 10) completely mess things up?

Thanks!

[Alliegirl]

My mare was short cycled the first week of May on day 10 and ovulated SIX DAYS later! It went so fast that we didn’t get the semen in time. I don’t have much good hard information for you, but apparently some mares ovulate very quickly. We decided to let her cycle normally after that… but even without giving her the lutalyse that time, she ovulated 17 days later (instead of the “typical” 21). Thankfully the SO was awesome and although her follicles grew at a rapid pace and much earlier than expected, we got semen in time and she was bred-- and is now 37 days along.

Good luck-- Mare is a 4-letter word!

[Sunnydays]

I have a mare who routinely has an 18-19 day cycle. If ever I want to short-cycle, having waited 6 days since the last ovulation, I make sure to get her to the vet within 48 hours of the Lutylase. In the past I have missed ovulation, waiting 3 days to ship.
This season a young mare ovulated 17 days after her last breeding (which was less than 6 hours post-ovulation). Could not get a vet out on day 16 or 17 (day 15 falling on a Sunday), so shipped her to the repro-vets on day 17, and she had just ovulated. No infections (checked twice with culture and cytology), so no discernible reason for the quick cycle. My mares just don’t follow the book.

[ElegantExpressionsFa]

I have a mare that ALWAYS cycles 18 days!! We were not successful cycling her in as she was all over the place and we missed her a few times that way…It took a few attempts letting her cycle on her own before we figured her out. Needless to say we just planned on her ovulating by day 18 and ordered the semen the day before because she was so fast…it worked like a charm when we did that. She would go from a 32mm in the morning to having ovulated by the following night on us twice before we clued in!! :S

I also had my other mare cycled in on a Wednesday (this is a mare that has ALWAYS taken 7-10 post lutalyse before she would ovulate!) thinking we had enough time to get through the weekend (the semen was coming from the US) …well, she decided to cycle in early and needed to be bred on Saturday…we did end up getting her in foal but at her 17 day check she was just in the process of reasorbing…we cycled her in again on a Thursday (18 days post breeding) and she was then bred on a Tuesday, she is now happily 73 days in foal

It would be SO nice if mares would read and follow the book that is for sure…best of luck with your mare!!

[rodawn]

Anytime you use Lutalyse, the mare will come into heat roughly 5 days after and ovulate 8-9 days after.

So, if you do the full 10 days of P&E with lutalyse or Estrumate on Day 10, you can expect her to be coming into heat by day 15 and will have ovulated by day 19 and fully out of heat by day 21.

Therefore you check your follicle size on day 16, plan for an AM semen collection day 17 and you plan to give Chorulon (HCG) in the PM of that same day.

Semen shipment to arrive AM of day 18… breed when semen arrives on day 18, flush 6 hours later, oxytocin, and she will ovulate overnight in day 19. Continue your standard oxy protocol for the next day or two.

If using frozen semen, you would use a straw at 2 intervals - 24 hours post Chlorulon (or HCG) and again at 40 hours post. This is so that you catch the ovulation within 2 magical windows of opportunity at close proximity to ovulation.

This is your standard 21-day cycle.

On approximately 80% of the mares. There’s always a couple who like to keep you on your toes. Still 80% is enough to say “almost always”. . .

This is courtesy the School Of Jos and Kathy, so I take no credit here.

[Equine_Reproduction]

Boy…no easy, one size fits all answer here. When short cycling a mare with prostaglandin, if the mare has a mid-cycle follicle, she often will come into estrus and ovulate very quickly. If there is nothing on her ovaries, by giving prostaglandin, you lyse the CL and will hopefully see a predictable growth of the follicles. Average time to ovulation is 9 days when using prostaglandin.

With P&E, you are essentially leveling the playing field on the ovaries. So, by day 10 of the protocol, there should be no follicles of any consequence. The prostaglandin is given in case there is a residual CL on the ovaries. The premise behind the protocol is that mares will “usually” grow follicles at a predictable rate of 3 to 5 mm’s a day, thereby giving you a 35 mm follicle at a predictable day on which you can use an ovulation promoter. BUT, with all of that said, one must also consider that mares emphatically refuse to read the books on how they are SUPPOSED to respond ;). Goodluck!

[jdeboer01]

[QUOTE=Equine Reproduction;6404311]
Boy…no easy, one size fits all answer here. When short cycling a mare with prostaglandin, if the mare has a mid-cycle follicle, she often will come into estrus and ovulate very quickly. If there is nothing on her ovaries, by giving prostaglandin, you lyse the CL and will hopefully see a predictable growth of the follicles. Average time to ovulation is 9 days when using prostaglandin.

With P&E, you are essentially leveling the playing field on the ovaries. So, by day 10 of the protocol, there should be no follicles of any consequence. The prostaglandin is given in case there is a residual CL on the ovaries. The premise behind the protocol is that mares will “usually” grow follicles at a predictable rate of 3 to 5 mm’s a day, thereby giving you a 35 mm follicle at a predictable day on which you can use an ovulation promoter. BUT, with all of that said, one must also consider that mares emphatically refuse to read the books on how they are SUPPOSED to respond ;). Goodluck![/QUOTE]

Thanks Kathy! So, it wouldn’t make a difference if I were to give the prostaglandin on day 11 or 12? Or would that make the mare ovulate a respective day or two later?

[Equine_Reproduction]

[QUOTE=jdeboer01;6404806]
So, it wouldn’t make a difference if I were to give the prostaglandin on day 11 or 12? Or would that make the mare ovulate a respective day or two later?[/QUOTE]

In fact, it is possible that it might even make her ovulate a little earlier. Note that above I reference a rapid return to estrus and ovulation following prostaglandin treatment in the event that there is a mid-cycle follicle present. At the end of the P&E course (or at the end of the biorelease phase in the event the single-dose biorelease version is being used), there should be no follicles > 2 cm present on the ovaries. With the dropping of the estrogen level (in the P&[b]

E

[/b]) there commences a predictable release of FSH that causes a new wave of follicles to develop - some of which will be those <2 cm follicles already present. In the event therefore that there is (say) a 2 cm follicle present at day 10, then by day 12 it could hypothetically be 3 cm in diameter (working on the 3-5 mm daily growth rate). If one gives PGF2a to a mare with a 3 cm follicle (or bigger) present, then a rapid return to estrus and ovulation is likely to occur - in some cases (typically with a larger follicle) the ovulation may even occur within 24 hours.

In order to avoid the unpleasant side-effects of prostaglandin (sweating, cramping etc.) we give a one-tenth doses on two consecutive days. When doing that with P&E, we give it on day 9 and 10 of the treatment period. We have seen no reduction in reliability of the timing of the resultant estrus. I would not be inclined to treat with PGF2a on days 10 and 11 (or 11 and 12) though, as I believe that may affect reliability of timing.

Remember it’s only 90% of mares that respond predictably to P&E though, and only 90% of them that will ovulate on a predicted day, so don’t blame me if it doesn’t work!!!

Hope this helps.