Just had ultrasound done on bitch at 24 days and vet said she is probably not pregnant , is this realiable ? Was scan done too early ? Matings all went well and even had sperm tested and progesterone levels checked , so am nearly surprised and gutted that she may have missed.. Thanks
                

I would say that was too early, I had my bitch scanned on day 30 and puppies were seen. 

I'd be tempted to go back in a few days and have it done again, but don't give up hope yet.  :)

I would say it's a little too early too

we had ours scanned at 24 25 days and nothing showed our vet offered us a free scan a wk later and it showed she was preg ,

It depends entirely on the skill and experience of the operator.  I can find foetus at 21 days but other people tend to wait until 28 days.

I can find them at 21 days too, but vets tend to have a quick look and that's it.  My vet won't scan until 35 days.

I scan at 30 days

Thanks everyone you have given me some hope . We have done all we can . Fingers crossed . I'll let you all know..