Q: I am a vegan, and I want to feed my cats a vegan or vegetarian diet. What's your advice?
A: Veterinarians who specialize in nutrition recommend against feeding vegan or vegetarian diets to cats because research has shown that these diets are not over the long term.
Moreover, vegan and vegetarian diets don't make sense biologically for cats:
Cats are obligate carnivores, meaning they require meat. They have evolved to eat small rodents, so their teeth and jaws are designed to grasp and tear prey, not chew and grind plant material.
Cats have much higher protein needs than dogs or humans, and they must consume many amino acids because they either can't produce them at all or can't produce them in the quantities their bodies require.
Plant-based diets contain little of the amino acid methionine, which cats need in large quantities or they suffer dermatitis and poor growth. Another example is arachidonic acid, a fatty acid found in animals, but not plants, that is needed for proper function of the brain, muscles and immune system.
Cats can't digest carbohydrates well. In the wild, they remove the contents of the rodent's stomach and intestines before they eat these organs.
Cat saliva lacks the enzyme that starts carbohydrate digestion. Enzymes in the feline pancreas and intestines that digest carbohydrates are barely active. Cats also lack the enzyme that initiates glucose metabolism.
Compared with omnivores like dogs, cats have a small stomach and short intestines with few of the bacteria that help digest starches and fiber.
To make matters worse, plants contain large amounts of fiber and phytate that block the absorption of some necessary trace minerals, including copper, iron and zinc.
Obligate carnivores such as cats handle vitamins differently from omnivores, too. Omnivores can ingest beta-carotene in plants to make vitamin A, but cats don't have this metabolic pathway, so they need to ingest vitamin A itself, which is found only in meat. Cats also can't make vitamin D in their skin as humans do, so they need a dietary source, like liver or animal fat.
Meat-based diets acidify the urine, whereas plant-based diets make it alkaline, which increases formation of urinary stones that can obstruct the urinary tract, especially in male cats.
Please honor this difference between yourself and your cats, and feed them the meat-based diet they need.
Q: My veterinarian recommends that Greta, my 8-year-old beagle, have senior wellness lab testing this year. Will the tests tell me if she has cancer?
A: Senior wellness lab work does not include tests that specifically prove a dog has or is free of cancer. However, certain abnormal test results raise the suspicion of cancer.
For example, Greta will have a complete blood count that measures red blood cells, white blood cells and platelets. Elevated levels of eosinophils, one type of white blood cell, are associated with cancer but also with parasites and allergies. A low red blood cell count, called anemia, also may suggest cancer.
Senior wellness lab work includes a chemistry panel to evaluate kidney and liver function, antibody and protein levels, blood sugar, cholesterol, electrolytes and more. On the chemistry panel, elevated calcium levels raise the suspicion of cancer.
Your veterinarian will probably do a urinalysis, part of which involves examining the urine under the microscope to look at, among other things, the cells that line the bladder. If they look abnormal or there are too many of them, your veterinarian may suspect bladder cancer.
Female beagles over 6 are at higher risk of bladder cancer than other dogs, so your veterinarian may also recommend testing Greta's urine for abnormal cells using the CADET BRAF test.
If Greta's physical exam and lab results are normal, you and she can relax and enjoy your lives together.
Lee Pickett, VMD, practices companion animal medicine in North Carolina. Write to her using the contact page at askthevet.pet/contact-us/