What could cause my dog to pant and whine a lot 2 days after being spayed?

 What could cause my dog to pant and whine a lot 2 days after being spayed? She was 51 days pregnant when it was done and she is a 6-year-old former puppy mill mom that we just rescued.

I'm actually very surprised a vet was willing to spay an animal that far into a pregnancy. Your dog was only days away from giving birth. That was an extremely late abortion.

I would call the vet ASAP. Spays during even an early pregnancy are much more complicated. Hormone shifts will be fairly dramatic. There is much more bleeding during surgery done during pregnancy or a heat cycle than during a spay done at other times.

It sounds like at the very least your dog's pain isn't being controlled. Pain certainly can cause a dog to whine and pain sometimes causes panting. Blood loss from surgery (or worse, internal bleeding after surgery) can also cause panting because the loss of red blood cells reduces needed oxygenation.

I would not delay in calling your vet. Your dog has not had a routine spay. She's had a much more complex surgery and sometimes things do go wrong. It's possible the loss of her advanced pregnancy and the resulting hormone shifts are causing your dog to feel distressed. And distressed dogs do sometimes pant in addition to whining. But I would not decide the problem is "psychological" and delay seeking treatment. I hope it's not anything serious, but something could be wrong physically.

Honestly, if it were my dog, I'd take her to an emergency vet if my regular vet wasn't open. (I'm answering this question from the US late on a Sunday afternoon.)

Thanks for the A2A. Good luck! I hope everything is ok.