In the month of September, Dublin Animal Hospital focuses on the health of our beloved senior pets. As they age, they are most susceptible to certain diseases that can ultimately cause them to pass away. As a pet parent, it is important to recognize the symptoms of these diseases and bring them to a veterinarian for treatment.

Old golden retriever laying on the grass

There are four major causes of death in older dogs:

Cancer: A 2011 study from the University of Georgia showed that cancer (neoplasia) is by far the greatest cause of death in older dogs. This study shows that cancer is a disease associated with aging and that it is far more common in older dogs than younger dogs. Despite claims that cancer is usually due to exposure to environmental toxins, commercial dog food, vaccination, etc. the figures show that cancer “increases with age in all breeds regardless of differences in lifestyle and that it also becomes less common in the oldest individuals.” Dogs who live to old age (past 10 years old) are relatively less likely to develop cancer since they were born lucky with protective genetics.

The article below by The SkeptVet summarizes it nicely as:

In short, cancer occurs largely as a result of the interaction between genetic risk factors and age, with lesser contributions from environmental influences that also interact with genetic factors. Cancer is what you die of if you’ve avoided dying of infectious disease and trauma and lived long enough to get it. The relative increase in cancer as a cause of death in our dogs over the last few decades is a sign of our success in reducing the importance of these other causes, not a damning indictment of our toxic environment or nutritional and vaccination practices.

Symptoms to look for: lumps or bumps on the body, changes in weight, sores that heal slowly, drooling, coughing, excessive panting, difficulty eating, extreme tiredness, diarrhea, constipation, blood and mucous in the stool, or bleeding from the mouth, nose, or ears.

Heart Disease: According to a 2009 study in the Journal of Veterinary Internal Medicine, about 10% of all dogs have heart disease. The incidence of heart disease in dogs increases substantially with age.

  • About 10% of dogs between the ages of 5 and 8 years can be affected
  • 20-25% of dogs between the ages of 9 and 12 years can be affected
  • 30-35% of dogs more than 13 years can be affected
  • 75% of dogs over 16 years can be affected

75% of canine heart disease in North America is caused by chronic valve disease. When the heart valves “leak” and does not form a perfect seal, the blood can pump backward, resulting in too little-oxygenated blood reaching the rest of the body.  The leaking causes a heart murmur, which can be heard with a stethoscope. Heart valve disease is most common in small to medium sized male dogs.

Symptoms to look for: Coughing, difficulty breathing, changes in behavior, lethargy, depression, poor appetite, weight loss or gain, a bloated belly, collapsing, fainting, weakness, nighttime restlessness, or isolation.

Cat pillow, dog blanket

Liver Disease: Discussing liver disease is difficult because symptoms and life expectancy vary widely depending on the cause, severity, and pet’s overall health. The liver aids in digestion produce proteins for blood clotting, removes toxins from the blood, and stores vitamins and minerals. Liver disease can result from genetics, infection, trauma, as a side-effect of certain medications, toxin ingestion, untreated heartworms, diabetes, or aging. Liver disease results in inflammation, known as hepatitis. If left untreated, hepatitis can lead to loss of function as healthy liver cells are replaced by scar tissue. After diagnosis, pets with appropriate management and veterinary care can live several months or possibly even years. Because the liver does so much, it has a wide range of symptoms.

Symptoms to look for: Confusion, yellowish eyes/ tongue/ gums (jaundice), loss of appetite, weight loss, vomiting, diarrhea, increased thirst, instability, increased urination, weakness, blood in urine or stool, seizures, dark colored urine, or a bloated belly.

Kidney Disease: The kidneys are responsible for balancing certain substances in the blood and removing waste. When the kidneys fail and blood is not filtered, it results in the body essentially being poisoned as toxins accumulate. Many things can cause kidney failure to occur- kidney stones, a bladder rupture, toxin ingestion, infection, urinary obstruction, or aging. One cause of kidney disease is advanced dental disease, where the bacteria causing tooth decay enters the blood stream and causes irreversible damage to the heart, liver, and kidneys.

Symptoms to look for: increased thirst, increased urination, having accidents in the house, apathy, loss of appetite, weight loss, vomiting, loss of coordination, brown discoloring on the tongue, or an ammonia smell to their breath.



Fleming JM, Creevy KE, Promislow DE. Mortality in north American dogs from 1984 to 2004: an investigation into age-, size-, and breed-related causes of death. J Vet Intern Med. 2011 Mar;25(2):187-98.

Analysis of the Study:

Atkins C, Bonagura J, Ettinger S, et al. Guidelines for the diagnosis and treatment of canine chronic valvular heart disease. J Vet Intern Med. 2009;23(6):1142–1150.