It's been awhile since we spayed...
In fact, it was the summer of 1991 for our 3 girls ( "golden retriever", "collie", and "german shepherd"), womb-mate sisters. 2 of them had 13 puppies between them, but the golden retriever had none (and she was "Auntie" to the pups).
All 3 went into the clinic in the morning, and came home late afternoon the same day. NO incisions, NO pain meds, etc. They had no discomfort whatsoever.
I have no idea "what" the Vet 'did' (it didn't look like they were 'spayed' by todays' standards) but they never went into heat, nor had any litters after that.