The Complete Guide to Dog Health: Vaccines, Parasites, Dental Care and Checkups

Key takeaways

• Preventive care comes down to four habits: vaccinate on a schedule that fits your dog’s risk, use year-round parasite prevention, keep teeth clean, and keep your dog lean. Regular vet checkups tie them together.
• Vaccine guidance has moved toward fewer boosters for core vaccines once a dog has finished its puppy series and first-year booster. Your vet should tailor the plan to your dog’s lifestyle and location ¹.
• Parasite prevention is recommended all year in many regions, not only in summer, and heartworm testing is advised yearly ^3,9.
• Dental disease is extremely common in adult dogs and is largely preventable with home care and professional cleaning ^4,5.
• Weight and body condition should be checked at every vet visit ⁷.
• Most adult dogs benefit from a checkup at least once a year. Mature and senior dogs are usually seen every six to twelve months ⁸.

Why preventive care matters

Most serious, costly dog health problems are easier to prevent or catch early than to treat late. A dog that has its teeth checked, its weight tracked and its parasite prevention up to date rarely ends up in the emergency clinic for something avoidable.

Veterinary organizations such as the American Animal Hospital Association (AAHA) organize preventive care around life stages: puppy, young adult, mature adult, senior and end of life. Each stage has different priorities, and the care a dog needs also varies with its size, breed, lifestyle and health ². A Great Dane and a Chihuahua reach “senior” at very different ages, and a dog who hikes and boards often has different risks from one who rarely leaves the yard.

For that reason this guide explains principles instead of handing you a single calendar. Your veterinarian knows your dog and your region, and should set the specific schedule. The guide is organized by topic first (vaccines, parasites, teeth, weight), then by life stage, then by what you can do at home.

Vaccinations

Core vaccines

The World Small Animal Veterinary Association (WSAVA) names three vaccines as core, meaning every dog worldwide should have them: canine distemper virus, canine adenovirus (which causes infectious hepatitis) and canine parvovirus ¹. These diseases are serious and often deadly, and the vaccines protect most dogs very well. In many places rabies vaccination is also required by law, so follow your local rules.

The puppy series

Puppies receive some immunity from their mother’s milk. This “maternal antibody” protects them early on, but it can also block a vaccine from working, and the amount varies from puppy to puppy. Because no one can tell exactly when a given puppy’s maternal antibodies fade, WSAVA recommends giving several core vaccine doses every two to four weeks, with the final dose at 16 weeks of age or older ¹.

In practice this means a puppy is not fully protected until the series is complete. If you adopt a puppy whose history is unknown, tell your vet; they may recommend a different plan.

Boosters

After the puppy series, a booster is given later in the first year, on the schedule your vet follows. WSAVA’s guidance is that after that, core vaccines generally do not need to be repeated more often than every three years in most dogs ¹. Your vet may recommend a different interval depending on the vaccine products they use and the local law.

Non-core vaccines

Some vaccines are recommended only when a dog’s risk justifies them. Leptospirosis is treated as core in places where it is common ¹. Others, such as vaccines against kennel cough (infectious respiratory disease) or Lyme disease, depend on whether your dog boards, attends daycare, travels or lives where the disease occurs. WSAVA notes that respiratory vaccines are non-core for typical pet dogs but should be considered for dogs living in shelters ¹.

Questions about vaccine safety

Most dogs have no reaction or only mild, short-lived tiredness or soreness after vaccination. Facial swelling, hives, repeated vomiting or difficulty breathing after a vaccine are urgent: call your vet or an emergency clinic straight away. If your dog has had a reaction before, tell your vet before the next vaccine so they can plan around it.

Socialization comes before the last vaccine

Many new owners keep a puppy at home until the vaccine series is finished. The American Veterinary Society of Animal Behavior (AVSAB) takes a different view: the first three months of life are the most important window for socialization, and puppies can begin well-run socialization classes from about seven to eight weeks of age, before the vaccine series is complete ¹¹. AVSAB’s reasoning is that behavior problems are a major cause of dogs being given up or euthanized, and that the infection risk in a well-managed class is relatively small when puppies are healthy and receiving their vaccines.

The same statement advises caution: avoid dog parks and other busy, unsanitary places where dogs of unknown vaccination status gather ¹¹. Good options include supervised puppy classes with a vaccination requirement, calm visits with healthy vaccinated dogs, and exposure to new people, surfaces, sounds and handling at home. Ask your vet to agree a plan, since local disease risk varies.

Parasite prevention

Four groups of parasites matter most for dogs: heartworm, fleas, ticks and intestinal worms. Several can also infect people, so controlling them protects your whole household ³.

Why year-round

The Companion Animal Parasite Council (CAPC) recommends year-round, broad-spectrum parasite control and annual testing for heartworm and other tick-borne infections ³. Its reasoning has two parts:

• In much of the United States, transmission occurs during most of the year, not just in summer.
• Owners are more likely to keep giving preventives if they simply give them all year, instead of trying to guess the season.

Heartworm

Heartworm disease is spread by mosquitoes and can seriously damage the heart and lungs. The American Heartworm Society (AHS) recommends annual testing for dogs and year-round prevention ⁹. Puppies can begin preventives before they are old enough to test positive, because it takes around six and a half months after an infected mosquito bite for a dog to test positive ⁹. Testing is also advised when changing from one preventive to another, and the AHS notes that most suspected preventive “failures” come down to missed or late doses and inadequate testing ⁹.

Fleas, ticks and worms

Fleas cause itching and can trigger skin allergies, and they carry other parasites. Ticks can transmit several serious infections, and the species and diseases vary a lot by region. Roundworms and hookworms can infect puppies from the mother and are also a risk to children, which is why vets deworm puppies on a schedule and test adult dogs’ stools regularly.

Choosing a product

Preventives differ in which parasites they cover, how they are given and which dogs can safely use them. Ask your vet to choose one for your dog’s weight, age, health and region. Never use a product made for another species, never split or guess doses, and keep a record of every dose so a missed one is easy to spot.

Dental health

Dental disease is very common. The US Department of Agriculture states that more than 80% of dogs over two years old have some degree of periodontal disease ⁵. It starts with plaque on the teeth, becomes tartar, and progresses to inflamed gums, pain, infection and tooth loss. Because dogs hide pain well, the first sign is often only bad breath.

What helps at home

• Brushing. Daily brushing with dog-safe toothpaste is the gold standard for home care, though many owners find it hard to keep up ⁶. Never use human toothpaste.
• Other options. According to the American Veterinary Dental College (AVDC), anything that reduces plaque and tartar helps, but some products are linked to broken teeth or gum damage ⁴. Hard chews, bones and antlers are the usual culprits, so ask your vet before offering them.
• Look for the VOHC seal. The Veterinary Oral Health Council tests dental products for plaque and tartar control. Its seal is a useful filter when you shop (see vohc.org).

How to start brushing

Most dogs accept brushing if you build up slowly. Let your dog lick a little dog toothpaste from your finger for a few days, then rub a finger along the outside of the teeth, then introduce a soft brush or finger brush. Keep sessions short and positive, and reward your dog afterwards. Puppies who learn this early are easiest.

What home care cannot replace

Brushing does not clean below the gumline. A professional cleaning under general anesthesia, with full-mouth dental X-rays, is how vets find and treat disease you cannot see. Veterinary dental organizations advise against “anesthesia-free” scaling because it cannot clean under the gums.

Warning signs

Bad breath that is getting worse, red or bleeding gums, dropping food, chewing on one side, pawing at the mouth, loose or broken teeth, drooling, or facial swelling all deserve a vet visit.

Weight and nutrition

AAHA’s 2021 guidelines recommend a nutritional assessment at every visit, including weight, body condition score and muscle condition score ⁷. Body condition is scored on a 9-point scale where 4 to 5 is generally the healthy range, and a dog scoring well above or below that is treated as having a nutritional risk factor ⁷.

A home check

A practical home check, to confirm with your vet:

• You should be able to feel the ribs under a thin layer of fat without pressing hard.
• Seen from above, there should be a visible waist behind the ribs.
• Seen from the side, the belly should tuck up toward the hind legs.

Keeping weight on target

Excess weight is a health risk in its own right, so it is worth taking seriously. If your dog needs to lose weight, ask your vet for a plan with a target weight, a measured daily amount and an activity schedule, instead of cutting food at random. Measure meals with a scale or measuring cup, count treats as part of the daily amount, and weigh your dog every few weeks to see the trend.

Muscle matters too: the guidelines assess muscle condition alongside body fat ⁷. Unplanned weight loss is also worth reporting to your vet.

For more on what to feed, see our upcoming guide to dog nutrition.

Checkups by life stage

AAHA’s guidelines divide a dog’s life into five stages and stress that timing depends on the individual dog ².

Puppies

Expect frequent early visits for the vaccine series, parasite control and a first check of the puppy’s overall health. This is also the time to talk to your vet about socialization, training, nutrition for growth, microchipping and when to spay or neuter, which depends on breed and size.

Young adults

This stage is usually the quietest for health problems, and the easiest to neglect. It is when the habits that matter later get set: tooth brushing, a steady weight, regular exercise and year-round parasite prevention.

Mature adults

As dogs move into middle age, vets look for early changes: weight shifts, dental disease, stiffness and lumps. The AAHA life stage checklist lists exams every six to twelve months for mature adult dogs ⁸.

Senior dogs

AAHA defines a senior dog as one in the last 25% of its estimated lifespan, which depends on breed and size ¹⁰. Senior care adds regular screening tests to examinations and pays particular attention to mobility, pain and cognition. The guidelines give a memory aid for canine cognitive dysfunction, sometimes called “doggy dementia”: changes in disorientation, social interaction, sleep-wake cycle, house-training, activity level and anxiety ¹⁰. Early signs are easy to miss, so mention anything new to your vet.

The AAHA checklist also lists six-to-twelve-month exams for seniors, and AAHA’s senior guidance calls for more frequent exams and screening tests than for younger adults ^8,10. Many vets see seniors at least every six months.

End of life

Quality-of-life decisions are among the hardest an owner makes. Your vet can help you assess comfort, manage pain and plan, and there are specific AAHA end-of-life guidelines that clinics use. Talk about it before a crisis.

What you can do at home

A quick weekly routine catches many problems early. Run your hands over your dog’s body for new lumps or sore spots, look at eyes, ears and gums, check skin and coat for fleas or bald patches, glance at paws and nails, and note appetite, drinking, energy and bathroom habits. Write anything unusual down with the date, because vets find a timeline very helpful.

Keep a simple health file with vaccine dates, parasite preventive doses, weights, medications and your vet’s contact details, plus the number of the nearest 24-hour emergency clinic. Make sure your dog wears an ID tag and is microchipped, with up-to-date contact details.

Questions to ask your vet

1. Which vaccines does my dog need, given where we live and what we do?
2. Which parasite preventive suits my dog, and how long should I give it each year?
3. What is my dog’s body condition score, and what weight should we aim for?
4. When should we do a professional dental cleaning, and what should I do at home?
5. What changes should I watch for as my dog moves into the next life stage?
6. How often should my dog come in, and what screening tests are worth doing?

FAQ

Do adult dogs still need vaccines? Usually yes, but not every year for every vaccine. Core vaccines are generally boosted at longer intervals after the first year, while some non-core vaccines are given more often depending on risk ¹. Your vet will set the plan.

Is parasite prevention needed in winter? CAPC recommends year-round prevention ³, and the AHS recommends year-round heartworm prevention ⁹. Your vet can tell you how this applies in your region.

How often should I brush my dog’s teeth? Daily is ideal ⁶. Any regular brushing is better than none, and your vet can show you how to build the habit.

How do I know if my dog is overweight? Use the rib and waist checks above, and ask your vet to score body condition at each visit ⁷.

How often should my dog see the vet? Most healthy adult dogs benefit from at least a yearly exam. Mature and senior dogs are usually seen every six to twelve months, and sometimes more often ⁸.

Can I treat my dog’s symptoms at home? Do not give human medicines, which can be dangerous to dogs. Call your vet for advice first.