This is a big lottery, it depends heavily on how the particular doctor operated and it also depends heavily on the effects of hormone deficiency.
It depends very much on the prior sexual life. The other aspects result mainly in variable risk and hormone-driven sexual interest, as heat cycles are no longer given.
If the female dog is experienced and enjoying it much (with a human), the risk for extreme reduction in her sexual drive can be significantly lower. As it is to quite a big part based on the dog's own interest. A dog which had no sexual experiences beforehand spay (or in male case: neutering) will have a very hard life to develop this interest, if at all. But a dog which has it already.. doesn't need to change much after such a surgery.
My recent dog had not the slightest reduction in her interest and multiple orgasms were as well possible after spaying, even as she took a bit more time / stimulation and was easier oversensitized, took longer breaks in-between. Surely it as well depends on the surgical measures, but a standard ovariohysterectomy leaves much room for her individual mental and interest-based requests of sexual activities.
And no, the hysterectomy was not based on pyometra, but malign tumors. On a pyometra with early recognition and limited infection areal I would never accept the surgery.
There is a hormonal treatment that can be used to stop the heat (here Covinan), but it is only safe for occasional use.
I know, there are as well chemical temporal castrations for male dogs available. But the side effects fill quite long lists for all of those chemical concepts, possible health-related problems are not that rare, as such no drugs I would ever recommend.
Even if it existed, sterilization would be forced through propaganda.
A common problem.
Only thing which helps in relation to the owners is counter-propaganda based on facts:
- Food acceptance and intake can vary, it's easier for female dogs to build up fat.
- Incontinence can follow quite often.
- Changes of the character and emotional balance are possible.
- This as well influences often the acceptance or unacceptable behavior in relation to other dogs.
- And - happened to the dog girl of a good friend of mine - if the veterinary didn't remove the stump completely, it's unfortunatly still possible to gain a stump pyometra. As such this risk is even with full "spay" ovariohysterectomy not completely nullified, if small remains stayed.
- One of the worst ones for long-haired dogs with underfur aka two layered fur: The heat cycles respective hormonal changes are directly linked to fur-change cycles. Without the hormonal origins it is not rare that the fur grows all year around and as well sheds.. all year around.
This resembles loads of lost hairs, possible scratching, four to five times more work with combing / removing underfur and so on. Fur pattern changes as well, either overly fattening or very straw-like, both can occur. And that's very stressing for any owner.
Been there, done that. As such.. No thanks to ovariohysterectomy, if it doesn't save the dog's life from otherwise deadly metastases.