Alright friends… I’m newer to breeding and just breed for the first time using frozen. My Old NA approved TB mare is in foal to Cor Noir. To get her in foal, it took a total of three doses over two cycles. I used a very good and reputable equine repro vet in our area, and they followed the two dose protocol by SBS ( which was what I want to do also) but my mare had a bad inflammatory response and didn’t take despite all efforts. The second cycle we breed her with one dose that was perfectly timed between two follicles. And she took!!! Yahoo!
But I often hear many of you seasoned breeders talking about catching your mare off of only one straw!!! How do you do that??? I’m sure it’s great timing and great quality semen… But still?
I’d love some very practical advice on breeding with frozen out of your personal experiences.
How do you decide when to use only a straw or a couple straws verses a dose or two doses?
Okay, well, there are a number of factors at play when using frozen semen.
First, if your mare has a bad inflammatory response to frozen semen, it could be that she is a marginal mare for frozen. I mean by marginal in that as long as your vet can control the inflammatory response, she might have a chance to get pregnant. This mare would probably be very fertile with fresh-chilled shipped semen. For whatever reason, some mares just don’t like the frozen semen, probably because most of the natural fluids are centrifuged out so that there is just a semen pellet that is processed with freezing extender and put into the straws. Fresh-chiilled semen has not only the antibiotic extender to extend the life of the semen, but most of the seminal fluids which act as a natural buffer.
My vet does a number of things to control post-insemination inflammation. First, he uses the smallest amount of semen possible - the more semen you use, the more she has to clear, the more likely she will develop an inflammatory response. An inflammatory response is the natural response of the uterus to the introduction of something foreign. Semen is foreign, therefore, the uterus responds to it. Only if absolutely necessary, will he attempt a deep horn insemination and that’s only if the stallion’s fertility is known to be marginal. it’s better for the mare to not go deep because any time you have to enter the uterus to inseminate there is always a risk of introducing a bacteria and getting a bacteria way up deep can be a nasty problem to deal with.
For frozen, he likes the semen into the mare about 2 hours prior to ovulation to at most 4 hours post ovulation. Which means, he is watching the mare like a hawk on ultrasound trying to get the timing JUST RIGHT. The timing has to be perfect and you need a skilled and willing vet for this. With fresh, my vet wants the semen in about 8-12 hours prior to ovulation preferrably.
Also, he will do a post insemination flush about 4 hours later to help reduce/minimize inflammation. (Note: A mare who carries a lot of chronic fluid or develops massive fluid response in the uterus post insemination is not a good frozen semen candidate because a lot of chronic fluid indicates a mare who already has an inflammatory uterus to begin with. An irritated inflamed uterus becomes a hostile environment for an embryo and ideally we want a nice peaceful, quiet uterus waiting for the embryo).
At the end of the flush, he instills Oxytocin and follows an oxytocin protocol. This means, the mare is injected with oxytocin round the clock every 6 hours for 2 days, sometimes even 3 days, depending on the mare. Usually, to save my vet time and give him his much-deserved sleep, I tend to take on this protocol regimen myself.
For some mares, putting them on a small-dose regimen of anti-inflammatory medication, such as banamine for 2 days prior to breeding and 1-2 days post breeding also is helpful. This should only be done if your vet 100% WILL flush out the uterus post insemination, because you are inhibiting a natural response of the uterus to clean itself out. There is no documentation, per se, about this use, but I have used it successfully in my breeding program for the odd mare who, despite all attempts, still tends to go way overboard for inflammatory response and the result is she gets pregnant 1-2 cycles. So, this is just my personal observation.
Whether or not you use 1 dose per cycle, or a 1/2 dose per cycle, or have to resort to using 2 doses totally depends on the fertility of your mare and the known fertility of the stallion. It can also depend on the timing of the vet. If your vet happened to anticipate too soon her ovulation and used a dose, and then she hung onto the ovulation (not always the vet’s fault - these mares tend to make their rules as they go), you might need another dose to play catch up. Some stallions are not good candidates to split doses. Some mares are not good candidates to split doses. When you have a mare who gets pregnant with the stallion just nickering at her, so-to-speak…this is a fertile mare. If his reputation is “if he can’t get a mare pregnant, this mare is never getting pregnant”, well, then he is a highly fertile stallion. Pair the 2 together and you could safely split the dose and get more than one pregnancy with one dose of semen.
Example: I have a mare that is so fertile it’s crazy - semen gets put in on Friday night. She ovulates on the right ovary. 4 days later, ovulates AGAIN, this time on the left ovary. We did not instill any extra semen other than the dose she got on the Friday… she will get pregnant, consistently, on both ovulations and the twin will have to reduced. THAT is a fertile mare. (Fertile stallion too).
Kathy or Jos or someone else will most likely have more points to add, or clarifying (sometimes I’m not the most clear, and I am fighting a migraine today…)
Again, thanks to Kathy/Jos for their articles, all credit to them: http://www.equine-reproduction.com/articles/oxytocin.htm
http://www.equine-reproduction.com/articles/Timed-Insemination.shtml
http://www.equine-reproduction.com/articles/FrozenSemen1.htm
Thanks for the great info Rodawn!
Have you ever used just one straw on a breeding?
Hi there Piedmont 
I have a 2012 weanling by Cor Noir. Mare was inseminated with one dose protocol.
Once she’s at around 35mm I give her Deslorelin around 4 in the evening and then drop her off at the clinic the next morning and she stays there to be U.S every few hours around the clock until it’s time to inseminate. Immediately after a shot of Oxytocin and then,don’t know what the window for timing is, but several hours post breeding, lavaged!
She is in foal again to Cor Noir, again one time breeding ,single dose 
“The most reliable way to use one dose of frozen semen is to inseminate post-ovulation. Post-ovulation inseminations must be made within 6-8 hours of ovulation due to the lifespan of the ovum within the oviduct. Obviously, the closer to ovulation the insemination is made, the better the result, this is true for fresh and frozen semen. The one dose insemination protocol generally involves single daily ultrasound examination until a 35mm pre-ovulatory follicle is detected, then administration of an ovulation agent (hCG or Deslorelin). The mare would then be checked 12 – 24 hrs after administration of the ovulatory agent and every 6 hrs (range 4-8hr) thereafter until ovulation is detected, at which point insemination occurs. Insemination can be performed pre-ovulation, however it is difficult to accurately predict when a follicle will ovulate, therefore it is preferable to wait for ovulation to occur and inseminate within six hours rather than risk losing a dose on a premature pre-ovulatory insemination.”
