We want the best for our pets, so we might want to give them a multi-vitamin “just in case.” Here’s what I told a reader about whether or not that’s a good idea.

Q: I want to make sure my pet has the best nutrition. Should I give him a multivitamin?

A: If your dog or cat is already eating a complete and balanced diet — it will say on the bag or can if it is — a multivitamin isn’t necessary. It can even throw off your pet’s nutritional balance. But there are times when a dog or cat can benefit from one, and I asked Joe Bartges, DVM, DACVIM (Nutrition), a board-certified veterinary nutritionist at the University of Georgia, to weigh in on when one might be helpful.

One time is when a pet is eating a homemade diet, he says. Those multivitamins can be recommended by a veterinary nutritionist after evaluating what your pet is eating.

And sometimes vitamin and mineral supplementation can help in treating a disease: “For example, (give) vitamin B12 — cobalamin — with gastrointestinal disease; vitamin D3 — calcitriol — with chronic kidney disease; (and) potassium in cats with low blood potassium due to chronic kidney disease,” he says.

Don’t give pets your own vitamins. The amounts of vitamins and minerals they contain aren’t appropriate for pets — and can even be toxic. “For example, vitamin D content in some human vitamins is high due to osteoporosis, and this could result in overdosing, depending on the vitamin D content in the pet’s diet,” Dr. Bartges says.

Vitamins and minerals may be natural, but they’re not always harmless. And giving too much of anything can cause problems. “If someone gives too much calcium, particularly to a large or giant-breed dog who is consuming a reasonable amount of calcium in a good diet, this can lead to too much calcium intake, which has been shown to increase the risk of developmental orthopedic disease,” Dr. Bartges says.

There’s more in Pet Connection, the weekly nationally syndicated pet feature I co-write with Kim Campbell Thornton and my daughter, trainer Mikkel Becker.

A reader’s male cat has been suffering from bladder stones and wrote asking if that special diet is really necessary. Here’s what I had to say.

Q: My male cat has bladder stones, and the vet is recommending a special diet. It’s expensive! Is there some natural way to treat or prevent the stones?

A: Some conditions and diseases in pets are best managed through diet, and one of them is bladder stones. Peer-reviewed studies have shown the benefit of veterinary therapeutic diets for dissolving these stones.

Urinary stones are seen in 10% to 20% of cats with lower urinary tract disease. In male cats, stones can block the urethra — the tube that carries urine out of the body. That’s a serious medical emergency! Cats unable to urinate can die within 72 hours if the blockage isn’t relieved.

Changing a cat’s diet helps in several ways. Switching to canned food, which is approximately 70% water, helps the cat take in more fluid. And some diets are formulated to produce acidic urine, which is more likely to dissolve struvite stones. Therapeutic diets also tend to be higher in sodium, encouraging the cat to drink more water. That, in turn, dilutes the urine, making it less likely that crystals will form into stones.

Using diet to dissolve stones is less invasive than surgery — the other option for stone removal — but the drawback is that it can take several months to work. Be patient, and don’t undermine it by giving your cat other types of food or treats.

To help the food do its work, scoop the litter box at least a couple of times a day so your cat will want to use it, and make sure he always has plenty of fresh water. Consider getting a pet fountain to increase his interest in drinking more often; lots of cats prefer running water.

Catching this problem early and treating it effectively with an appropriate diet is the best way to prevent it from becoming worse.

There’s more in Pet Connection, the weekly nationally syndicated pet feature I co-write with Kim Campbell Thornton and my daughter, trainer Mikkel Becker.