How common is a false heat?

I searched this topic but was wondering how common a false heat is during pregnancy?  We combined cows from 3 pastures last week on Thursday and yesterday I had two of the better cows (typical) seem to be in heat. They both came from the same pasture. Two of the bulls were following them around and tring to jump them for over a day but the two cows wouldn't stand at all.  I found it interesting that the bull they were with in the pasture all summer wasn't chasing them though. He was semen tested and bred all the cows he was with last year. I had recoreded one of them being bull bred on June 28 and the other July 1.  We are working the calves next friday so I will have these two preg-checked at that time but was wondering if it's possible this was a false heat in part to increased hormones when combing the cattle back into one group?  Any thoughts appreciated

I am not sure exactly how common it is overall, but I know it is much more common in heifers.  My bred heifer has come into what appears to be full blown heat every single month since she's been bred, but she's been pregtested to calve beginning of February.  The vet said it has something to do with her progesterone levels.  Sort of like how teenagers hormones are out of wack, it just takes a while for everything to regulate.  He told me she'll probably continue to do this until she calves, but that there shouldn't be any problems.

I don't really think a true false heat--when a cow is pregnant and will stand to accept a bull's service--is very common at all, but I have seen it happen...one time. That was a yearling heifer we AI bred then turned in a small lot by the barn with a herd bull for clean up. She did show heat, and he bred her, so we expected a calf from that natural service. She had twins 10 days early to the AI date...I'm not sure if it was a hormonal thing because of the twins or what. They were both heifers, but clearly not identical, for whatever that's worth.

I HAVE seen cows or heifers ride or try to mount other cows when pregnant when no standing heats occurred. I think that kind of activity IS pretty common, and while mounting other cows is a sign of heat, I don't consider that activity in and of itself, signs of a false heat. That's just normal activity. So if the cows weren't standing, then you may have a reason to be optimistic. If it was pretty apparent they either weren't standing YET or they may have been on their way out of standing heat, then I expect they were open for whatever reason.

I have a first-calf-heifer that was confirmed pregnant with a BIOPryn test back in June. Hadn't seen anything out of her until late August, and she was standing one day. There is a percentage of cows that don't conceive, and then there is another percentage that conceive and don't maintain the pregnancy for some reason. It may be a repro thing with the cow...it may not be her fault...maybe she got bumped just right by another cow? Regardless of the reason, the result is the same...open cows. We're usually left to try and guess why (if it matters) and then determine whether it makes any sense to carry that cow & make excuses for her until she gets back with the program. I've seen some that do and some that just don't.

A couple of weeks before our sale one year one of the heifers was in standing heat. When the vet was preg checking I said he probably didn't need to worry but since she was in the chute he did , he said she was 4 months . He explained that at that time in the pregnancy there is a major change in hormones and it was not that uncommon to see a false heat. The heifer did calve the next spring at her new owners and I have seen a couple do the same thing since!