I had my barn cats neutered at the farm. They did have to go into the house to recover from the sedation though. It was cold out and so they had to be kept warm until they could regulate their body temperature. She gave them all their shots too. She's the best!
When I was a kid our vet used to take care of our family dog at the barn sometimes too. This vet did both large & small animals. As he got older he would refuse to get out of the car to go into the vet's office so sometimes it was easier for the vet to just give him his shots when he was coming to the barn where we boarded. The nicest thing he did was to come to the house to put the dog to sleep at the very end.
Cats, like horses are commonly neutered under injectable anesthesia. Current standard of care for dogs is inhaled anesthesia along with monitoring. Horses are left open. Dogs do require suturing which takes time.
I have heard rumours they will but I haven't had to ask yet
I hear some of the farms go with the elasticator, I have to say I'm very curious as to whether or not it would work on an animal that could reach back there. I would think it would be a very effective & safe way to go- just like with the other farm animals.
My horse vet neuters small animals, but only at the office. He doesn't, however, neuter horses anymore. He's not as spry as he was a few decades ago. He refers most large animal surgery other than simple stitches to younger vets these days. It's kind of nice; if he says I need to send the horse in for tests, I know he thinks there's a real problem and he's not just trying to pay off the loans for some new piece of diagnostic equipment.
Not sure about my current vet, but when I was working at a farm in Wisconsin, he would absolutely do barn cats. He would usually charge nothing if he was already there = ) I of course found this out after I spent a LOT of money to get my new kitty neutered that I had found in a soybean field, haha. I believe his actual phrase was, "Sure, I'll do any barn cats right here on the bumper of my truck." Haha. I think he was only half kidding...
I worked at a rural s/n clinic that was a barebones nonprofit and we did a LOTTTT of "well we tried to do it with the elasticator" fixes. I would never recommend that...horrible, infected, nasty, ugh....
Male cats I couldn't see a problem doing at home...except for white ones which tend to have more bleeding issues. I mean the cleanliness is a risk you'd have to be willing to undertake as far as it not being a sterile environment, but the only tools involved are sedation, reverser, scalpel blade and some glue.
A dog I would not feel comfortable doing at the farm due to the fact that they are (I work in specialty surgery now but even in the barebones clinic) always intubated during surgery. They require gas to keep them under during the procedure and I'm not sure how you'd keep a dog under (even with an IV injection) for the length of time required for a neuter or spay. Never mind, practically, where you'd DO it...it'd be a very awkward thing to do on the ground and you'd need the dog balanced up on their back and tied...can't imagine the disaster if a female kicked a leg and flopped on her side during a spay. Without a doppler there'd be no way to monitor heart rate and without a CO2 monitor you'd have no idea if the dog was not taking sustainable breaths...
my horse vet had done the male barn cats, she will also come out and put down any animal and she will suture,give shots but i always have to tell her before she comes if she's going to see any of the small animals so she has the right meds with her, she takes care of quite a few farms with a large number of hunting dogs as well in a pinch, i was very grateful when she came out and euthed my gigantic mastiff who i could not have gotten into an office. i have a small animal vet also, he will treat horses and goats if you bring them to his office,he was the only one willing to do surgery on my goat, i have barn cats and rescue dogs who are not quite house pets so having someone come out to do some of the care or an emergency euth is handy, always had dogs and females cats done at the vets office.