I've used that shot before too. I think it's called Leutalyse. The first time I used it, if the vet hadn't told me what to expect, I would've been concerned. They pop out in a wringing wet sweat within 5 or 10 minutes. It's really weird. I guess it's like MEGA hot flash. I was having trouble getting this particular mare bred. She was 8 and had never had a foal. I had her cultured and she had an infection. We ended up having to infuse her with Gentamycin for 3 days in a row, then give the shot. It worked like a charm and I haven't had trouble with her since.
Yeah, it is scary the first time you use it. Luckily the reaction doesn't last but a few minutes.
The first time I used it on my mare it worked good. The second time, she did get pregnant, but sometime thru that winter she lost it.
I was glad this time we didn't have to use it. I don't know if the shot had anything to do with her losing it, but I feel better NOT having to go that route, but was going to if she didn't get pregnant soon this past year.
Becky