My Dog Ate Before Neutering. What Should I Do?


Preparing your dog for his neutering procedure is a very stressful time. 

It’s not just the pre-surgery instructions you need to follow to the letter, but also the feeling that you should make it up to him somehow. 

How can you refuse your beloved pet a small treat when you know what kind of surgery he’s going to have the next day? 

So, what can happen if your dog eats something before surgery? Is it bad? Should you reschedule the procedure? 

There’s no simple answer to this question and if you check out what various experts have to say about withholding food and water, you’ll find that opinions and recommendations vary.

Let’s try to shed some light on this question that bothers so many pet parents.

What can happen if a dog eats before surgery?

The reason vets instruct pet owners to withhold food and water from their dogs before surgery (any type of surgery, not just neutering) is that the animal might vomit while he’s under general anaesthesia.

There are various types of anaesthetics doctors use, but they work the same way. 

The problem is that while the dog is under anaesthesia, the brain maintains vital functions, like breathing and heartbeat, but not all of them. 

Among them the gag reflex, which is suppressed. The anaesthetic might make the dog nauseous and if he vomits during surgery, there’s the risk the regurgitated content of the stomach might be aspirated into the lungs. 

Your dog might get aspiration pneumonia, which is bad enough, but treatable. 

What’s worse is the dog choking to death as the stomach content gets in the lungs.

Bottom line, the vet told you to take away your dog’s food and water the night before surgery, so he goes into surgery on an empty stomach.

If there’s nothing to regurgitate, he won’t suffocate even if he does vomit.

How long should a dog be starved before going into surgery?

While it’s easy to understand why a dog shouldn’t eat before surgery, deciding how long should you let him starve is rather complicated. 

Some vets say no food (or water) after 6 pm, others set an 8-9 pm deadline, while some push the time limit to midnight.

This is not only confusing, but also very frustrating for you as a pet owner. 

After all, it’s you that has to take away the dog’s food at 6 pm, refuse him even a sip of water and also take him to the vet the next day, again without giving him a bite to eat or a drop of water.

Is it reasonable? Let’s find out!

The American Animal Hospital Association (AAHA) in its ‘What to Expect’ handout leaves it up to the practitioner to decide how long a dog should go without food or water.

You will be asked to withhold food for a certain time to reduce the risk of regurgitation and aspiration”

And again – “You may also be instructed to withhold water from your pet, depending on the veterinarian.

They do not offer any official guidance. 

It’s all up to the vet, which explains why some order you to starve your dog from 6 pm while others say midnight is good enough. 

And, yes, those six hours make a lot of difference to you and especially to your dog. 

And what does the American Society for the Prevention of Cruelty to Animals (ASPCA) has to say? 

They also perform spaying/neutering at their clinics and they are definitely more humane. 

If you schedule a procedure with them you are told that you don’t have to starve your dog at all. 

In fact, you can give him something to eat in the morning, before leaving for the clinic. As for water, your dog can drink right up to the surgery.

How long should you starve a puppy before neutering?

If you look at the AAHA client handout mentioned above they clearly admit that young dogs don’t need to fast as long as older ones before surgery. 

That’s because older pets have a slower metabolism and it takes them more to digest food. 

Also, they have greater energy reserves than younger animals. 

Now, most dogs going for neutering/spaying are young healthy animals with a good metabolism. 

Basically, a small dog shouldn’t be made to fast from 6 pm if he’s going to have his surgery the next day at noon.

Also, according to the ASPCA, puppies four months or younger should receive half of their usual breakfast on the day of their surgery, while dogs that are five months or older should only get a quarter of their normal meal. 

There are no restrictions on water, as far as the ASPCA is concerned, and this makes sense especially when it comes to young pups who are at a greater risk for dehydration. 

What to do if your dog eats before surgery?

You might be tempted to follow the ASPCA guidelines, but you risk getting in trouble with your vet. 

If you cannot resist your pet’s pleading eyes and you do offer him a quick treat way past the deadline set by your doctor, you need to come clean about it. 

Your dog’s welfare depends on that!

You will find out that in most cases the vet will decide the surgery can proceed. 

He will give you the stink eye, though, as you’re the one who disobeyed their order. 

The truth is a dog can get anaesthesia even if he’s had something to eat, but that requires a lot more work on the doctor’s part. 

Namely, they’ll have to monitor the dog carefully in case the animal vomits and make sure he doesn’t choke.

If you think about it, if a dog needs emergency surgery the vet will perform it even if the dog had a large meal an hour before. 

Doctors that are very strict and insist a dog shouldn’t eat anything starting from 6 pm the previous day just want to be sure they won’t have any trouble with the dog vomiting during the procedure. 

If your vet won’t do the surgery because you didn’t starve your dog, you can only reschedule or look for another more understanding doctor.

Should I give my dog his meds before surgery?

This is something you need to discuss with your vet. If your dog has a condition that requires daily medication, they will review the meds your pet is on

In some cases you might be advised to skip a dose or two, but in other cases they’ll tell you to give your dog the meds as prescribed. 

At the same time, if your dog has diabetes you need to discuss with your vet how starving might affect him and what can you do to adjust his insulin levels. 

Should I bathe my dog before surgery?

That would indeed be a very good idea. 

First of all, you want your dog to be as clean as possible to prevent infection. 

The vet will shave and disinfect the surgical area, but that wound will need a few days to heal and you don’t want it to come into contact with dirty fur. 

At the same time, you won’t be able to give your dog a bath before the wound heals completely, so it’s going to be at least a week. 

You should also clean and disinfect the dog’s bedding, for the same reasons. 

Once he gets home from surgery, it’s better to let him rest in a nice clean bed.

Should I take the dog out before surgery?

Many vets recommend limiting the dog’s activity the day before surgery. 

The idea is to avoid him getting some sore muscles, which would only add to his post-surgery misery.

When you take the dog out the night before surgery make sure to keep him on a tight leash so he doesn’t get to eat whatever he might find on the street. 

The same goes for the morning of the procedure, particularly if he didn’t get anything to eat since sunset the previous day.

You should also consider sectioning off a part of the house or crating the dog for a few days. 

The vet will probably recommend limiting the dog’s physical activity to allow the wound to heal properly. 

Can I feed the dog after neutering surgery?

When you get home with your pet after the procedure, he will still be confused from the anaesthetic, so he might not be interested in food. 

On the other hand, there are dogs who come home absolutely ravenous.

Don’t rush to give your dog a big meal even if you know he’s famished. 

Break his normal meal in smaller portions and feed them to him at regular intervals, like an hour or so. 

Make sure the food is easily digestible and won’t create any problem. 

Now it’s not the time to offer your dog treats that might make him sick or foods he hasn’t had before.

Stick to his normal chow for the time being.

Closing Thoughts

If your dog has something to eat past the hour indicated by your vet, it’s not the end of the world.

If your vet told you to take your pet’s food and water away at 6 pm, remember that other doctors say 9 pm is OK, while others see no problem if the patient has a treat right before midnight. 

These instructions are not set in stone. 

However, if you don’t follow the instructions to the letter, make sure to let the vet know about it. 

They’re responsible for your dog during surgery so they need to know if there’s a risk the dog might vomit. 

Sarah Pulsen

Hello, I have been in love with dogs since I was a little girl. I became even more infatuated with them when I was told by my Mum that I couldn't own one. Since I left home there has rarely been a time in my life when I have lived without a dog. My current dog is a Collie Terrier cross, called Ian.