I thought of not replying to this but instead want to use it as a chance to educate those who are willing to be educated.
My mentor, Nancy Christensen, has been breeding Dobermans for 50 plus years and knows more about breeding Dobermans in her little finger than anyone who can read all the books and websites and whatever garbage that makes them think you know a lick about breeding. I can tell you first hand, you think you know about breeding until you're in the trenches.
I've been in plenty of trenches, including animal breeding. There are right ways and wrong ways. There's patience and impatience. There's strong-arming an animal into submitting to your will, and there's giving it time to work-out its apprehensions or whatever else it has going through its head. Blocking its avenue of escape by restraining it and suppressing its ability to warn another animal off might feel like "comforting" or "helping", but that usually just aggravates the anxiety.
With precious few exceptions, I reject the "old fashioned" strong-arming, restraining, drugging, and impatience. If I learned anything from my mentors when it comes to animal handling, it's that the old methods and attitudes are worthless. I have a pretty good assortment of twitches, lip chains, hobbles, and long-expired sedatives that my mentor in horseshoeing convinced me I'd need someday. I never needed any of those typical farrier implements, working with some of the most difficult horses that other farriers tended to get in brawls with, because the though of using them made me feel uncomfortable and I somehow managed to do better than them simply "not being an impatient *******" when dealing with apprehensive animals who were used to getting a beat-down every time a farrier visited.
Here's my response to what I feel is worth responding too:
"Y'all chose the wrong day and strong-armed the bitch, who apparently wasn't quite ready" The bitch is taken to the vet for progesterone testing every day, she was ready, she was flagging and she was standing and per the very educated, many years and well reknowned vet, Dr. Milan Hess, she was ready. The dogs, on leash, were given ample time to say hi and they were playing, on top of that they see each other every Tuesday and Thursday. She was flagging, she was standing and even baring down, she was just scared when he tried to get on top of her. Yes, we muzzled her and held her, but not super tight, just enough to protect Maverick.
Dr. Hess is very knowledgeable from a medical perspective, I was referred to her a few years back and I found her to be very wise. However, you're confusing labs and a few physical signs with psychological readiness. Something wasn't right in what you describe. I would say it's far from uncommon for a female to have all the hormonal and most physical signs of being ready to stand, but needing another day before she's actually standing.
I've heard the "restraint is just for the sire's protection" plenty, too. I'm sure it's sometimes required by insurance companies whether it's really needed or not, but it sounds like you strong-armed an animal into doing something she was uncomfortable to begin with, for whatever reason. If she hadn't freaked-out, then the "safety" bit might fly, but as you described the situation, all was not going well, the bitch freaked-out, and that's when the muzzle came out and her owner restrained her. Sometimes doing that sort of thing has no lasting consequences, but I've had to remediate a lot of the consequences of this sort of behavior when an animal isn't allowed to work things out for themselves and they're hurried-along against their will. And yes, some of those mistakes I've remediated have been my own.
"Or, maybe she has health or temperament issues." Like Maverick this bitch is more than fully health tested and temperament tested. String of titles, she's just a maiden bitch. Similar to a virgin, she was scared. She's never been around male dogs who have tried to hump her, this is not an uncommon reaction and I think it was even mentioned earlier in this thread by another breeder.
Temperament testing is nice and well, but there are folks who give tests more credit than what they can see with their own eyes. If she was simply apprehensive, then she probably would get over that on her own fairly quickly. "Screaming bloody murder" doesn't sound like apprehension, but maybe you just didn't describe it very well? That phrasing, plus muzzle, plus restraining the bitch, is what doesn't set particularly well with me. Even if it was actually just apprehension, how would strong-arming her through it help? When a child is nervous about getting into the pool, is the answer to shove them into the deep end?
"I'm not sure you did Mav any favors by setting him up for his first mating experience to be like this." I'm 100% sure Mav would disagree with you. Oh and I guess the bitch would too since when she saw him tonight her tail was wagging and she was nearly pulling her owners arm off. I guess she takes rape pretty well
Animals do need to learn to interact appropriately with other animals in a variety of situations. Mav was deprived of figuring this particular situation out for himself due to human interference. Maybe you'll always be present to help him through live covers, but it sounds like he received some very mixed messages. Maybe it's just me, but if one animal is warning another one to back-off, I'd tend to let those social cues stand and let them figure things out for themselves. That's how manners are learned.
Also, animals typically rebound very quickly once they're out of a situation. That doesn't mean they don't remember and won't have problems if they find themselves in that same situation again, whether it's getting bathed or groomed, having its hooves/claws trimmed, or taking a trip to the breeding shed. Maybe it won't be a problem. Maybe the bitch will have a bigger freak-out next time she's mounted. Guess that'll be a surprise. Hope it goes well & no harm was done.
The bottom line is that strong-arming animals through a mating is generally not something to be proud of just because it was expedient and many breeders do that all the time. It works far better just to take a break and try again later.
FWIW, there's absolutely nothing wrong with sharing the rest of your observations. I think that much is useful for the folks who are curious, since many didn't grow-up around this sort of thing and probably won't ever experience it themselves.