My Dog’s Behavior Changed After Vaccination (Unraveling the Mystery)

Dog's Behavior Changed After Vaccination

Vaccinations are a crucial part of your dog’s health regimen, acting as its shield against various diseases. You would have gotten vaccinated as a kid or even as an adult as well.

But have you ever noticed your dog acting rather unusual after getting vaccinated at the vet?

You’re not alone!

Many pet parents observe changes in their furry friends’ behavior following vaccination.

It’s possible for vaccines to cause behavioral changes in dogs similar to those prompted by the diseases they protect against. Behavioral alterations can include a heightened state of aggression, an increase in fearfulness or a greater display of anxiety.

In this article, we will decipher what’s normal, when to be concerned and how to comfort your dog during this time.

Are Dog Vaccines Neccesary?

dog getting injection in leg

The necessity of vaccines for dogs has been a fiercely debated topic for very long.

Some dog owners strongly feel that vaccines tend to do more harm than good and should be avoided.

While there are dog owners who strongly believe in getting their dogs vaccinated to keep them healthy.

I do make it a point to keep my dog up to date with his vaccination due to how often we are out and about.

Common Behavior Changes After Vaccination

Don’t expect your dog to be all peachy after its vaccination. Most dogs will experience some form of adverse reactions for a few days.

Here are some common changes you can notice in your dog’s behavior.

Walking With A Limb

There most common ways of giving an injection are into the muscle or into the skin.

For vaccines, the vet will inject the contents into your dog’s muscle. This will usually be at its rear or front leg, depending on the vaccine.

An intramuscular injection is more painful as the needle used is thicker and it goes deeper into the muscle.

This can cause your dog’s leg to feel sore and tight for some time making it walk with a limp with an intramuscular injection.

A study has found that a vaccination into the muscle “optimizes the immunogenicity of the vaccine and minimizes adverse reactions at the injection site.”

When Playtime Takes A Pause

dog sleeping

One reaction that I often get after a vaccination is tiredness. You can expect your dog to experience a similar reaction too.

Your dog will be less energetic, prefers to sleep more or isn’t too eager to chase after its favorite ball.

Most of your dog’s energy is used to build a robust immune system against the disease it is being vaccinated for.

Turning Up The Heat

Another common reaction that you will notice in your dog is a mild fever.

Your dog’s body will be warmer to the touch and its temperature will be higher when using a thermometer to check.

Having a mild fever is a good thing after being vaccinated.

A fever invigorates your dog’s immune system to fight against the vaccination.

A little fever is your dog’s way of saying it’s on the job!

Missing The Munchies

The last thing on your dog’s mind, when it’s feeling lethargic and running a mild fever is food.

Your always greedy dog will be turning up its nose as its food bowl and doggie treats.

One trick that has often helped with my dog’s appetite is to add some homemade chicken broth to your dog’s food.

Not only can chicken broth help with your dog’s appetite but it also has some nutritional benefits for your dog.

Dealing With The Runs

dog pooping

When a vaccine is administered, it stimulates the immune system in a way that mirrors an actual infection.

This immune response can sometimes cause upset your dog’s gut flora, leading to diarrhea.

If you have a dog that gets stressed out when it’s at the vet, this stress can manifest in various physical ways, including causing an upset stomach or diarrhea.

You don’t want to further aggravate your dog’s already fragile digestive system.

Refrain from feeding your dog anything that isn’t ideal for its stomach.

Keep your dog’s food intake simple and easy to digest by feeding it boiled meat with some white rice.

When Should I Be Concerned About My Dog’s Behavior Change?

The above symptoms should only be temporary behavioral changes and last for a couple of days.

You should also notice your dog starting to get better as the days go by.

Any noticeable and sustained change in your dog’s behavior after a vaccination is worth paying attention to.

You should contact your vet immediately if these allergic reactions persist or you notice more severe symptoms such as:

  • Chronic diarrhea
  • Severe skin inflammation
  • Difficulty breathing
  • Seizures

Your dog could be having a severe allergic reaction to the vaccination and requires immediate medical attention.

Serious reactions to a vaccine can turn life-threatening very quickly.

It’s always better to be safe than sorry.

Why Is My Dog Aggressive After Getting Shots?

angry dog

Don’t be surprised if your normally sweet-tempered doggie has suddenly turned into a grumpy guard dog.

It is a sign that it is experiencing some pain and discomfort.

Your dog will be sore over their injection site for a little while, usually if you touch them right on that spot.

Your canine companion may also be a little less trusting of you because you allowed the vet to stick needles in its body.

How Is A Vaccine Reaction Treated At The Vet?

The most common form of treatment for an allergic reaction in your dog is an antihistamine such as Benadryl to reduce these symptoms.

More severe allergic reactions will require more aggressive treatment.

This can include injectable antihistamines, steroids or epinephrine to quickly reduce the reaction.

Your dog may also need intravenous fluids and oxygen support in more severe cases.

Can I Prevent These Adverse Reactions In My Dog?

It can be challenging trying to prevent your dog from feeling bad after a vaccination as each dog can react differently.

Some reactions are just an indication that the vaccine is doing its job by stimulating an immune response.

And you should just allow your dog to ride it out and let the vaccine do its job.

There are a few strategies you can employ to reduce the likelihood of severe reactions:

Do A Health Check

dog at vet

Ensure that your dog is in good health at the time of vaccination.

If your dog isn’t in good health, it may have a higher chance of experiencing stronger adverse reactions.

It would be best to wait until your dog is feeling better before arranging for the vaccination.

If your dog has had a bad reaction to a vaccine before and is due for another shot, please let the vet know beforehand.

The vet might recommend you skip the vaccination or do a titer test to measure the levels of antibodies in your dog.

Make Your Dog As Comfortable As Possible

Vaccination can be a stressful experience for dogs.

Providing a calming environment for your dog after the vaccination can help minimize stress-induced reactions.

It would be best to leave your dog alone for now and let it rest as much as possible.

Don’t get in your dog’s face and make it feel more irritable than it already is.

Or your dog could even be more clingy during this period and refuse to leave you alone.

What Vaccinations Are Important For Dogs?

There are a few vaccines that are known as core vaccines for dogs.

Core vaccines are considered vital for all dogs based on the risk of exposure, severity of disease or transmissibility to humans.

These core vaccines are for:

  • Canine parvovirus
  • Distemper
  • Canine hepatitis
  • Rabies


Are Dog Vaccines Required By Law?

Certain dog vaccines are mandated by law in many states for public health reasons. The rabies vaccine is commonly required due to its potential transmission to humans and deadly outcome. It is crucial to consult with a local vet or your city’s animal control department for accurate information

Which Dog Vaccines Are Annual?

Core vaccines like those for canine parvovirus, canine distemper and rabies are often given yearly. The frequency may vary based on factors such as the dog’s age, overall health, and risk of exposure.

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