Dear Dr. Fox:

We have a puppy, a German shorthaired pointer and Labrador mix, not quite 5 months old. She has had two urinary tract infections.

When she developed the second one, our vet did a urinalysis and said she had crystals in her urine. He prescribed Hills Prescription c/d dog food as a preventive for future problems, such as kidney stones.

Is this the treatment you would recommend? What causes this condition? Her infections cleared up after a course of antibiotics.

L.D., Alexandria

DF: It is not unusual for young female dogs to develop lower urinary tract infections, and they usually develop some immunity as they mature.But once a bacterial infection becomes established, inflammatory reactions in the lining of the bladder and urethra cause pain and straining, often with the passing of blood.

Cellular debris becomes the nuclei for urinary crystal formation, most usually struvite crystals, which are associated with abnormally alkaline urine, caused in large part by a high-cereal diet.

In an emergency, adding acidifying cooked organic tomato pulp was a popular remedy. Now, d-mannose (found in cranberries) is another preventive suggestion.

Try a dietary change, and encourage your dog to drink lots of water, even flavored with some home-prepared low-salt beef or chicken bullion.

Give your dog probiotics with low-grain or grain-free food, a selection of which is posted on my Web site, www.drfoxvet.com. I would have your dog finish whatever antibiotic treatment she is on and then stop. Phase out the costly manufactured prescription diet, and switch over your dog to a raw or freeze-dried dog food, if none of the diets on my Web site appeal to you.

In a dither over diet

Dear Dr. Fox:

Our Dice, a 14-year-old male cat, just left us, and we’re heartbroken. He was diagnosed with kidney failure. I can’t help thinking it may have been what we fed him for so many years.

In the past three years, we switched to Blue Buffalo wet and crunchy food, but he favored his Fancy Feast crunchies and Gravy Lovers wet food. Dice left behind our Bella, a 2-year-old female, who does not drink water but will eat Fancy Feast Gravy Lover’s canned food.

Are we doing her more harm than good? Can you suggest any other food? There are so many on your Web site, it makes me crazy!

We do not want her to go through what our beloved Dice went through, or any other cat, for that matter.

T.G., Fort Myers, Fla.

DF: There are many factors that contribute to renal failure in cats, and also in humans.

So many things can trigger autoimmune diseases, including kidney disease: the nutrition of the pregnant mother; what animals are fed; what contaminants in the environment animals are exposed to, especially in water and foods; and any infections and vaccinations they might have.

We have disrupted and poisoned the planet and have a lot of housekeeping and cleanup to see to. Carnivores such as cats, living high up on the contaminated food chain, are especially at risk. Organically certified whole-food ingredients, raw food and freeze-dried are the wave of the future for cats.

I get crazier than you checking all the ingredients and sources of origin of various pet foods, and the best that I have found are posted on my Web site, and by Susan Thixton on her site, www.truthaboutpetfood.com. Also check www.feline-nutrition.org for more leads on feeding cats.

GOLD DIGGER

Dear Dr. Fox:

I have always had pets, but never cats because of a severe allergy. My sister came to live with me for a few months several years ago, bringing her young cat.

The cat got along well with my dogs, bonding completely with my dog of the same age, but I started to notice some strange things.

First, the yellow heads from my son’s Lego figures would disappear. Then, I couldn’t find the yellow spring eggs I decorated for the season. My set of paints was missing the tube of yellow that I knew should be there. When I couldn’t find my favorite shopping bag (yellow), I began to suspect the cat.

I spread out some multicolored pompons on the table where we kept his food and counted how many of each color there were. Sure enough, by morning, there were no yellow pompons, but none of the other colors had been touched. The same was repeated with multicolored feathers. When we checked the cushion of the cat’s preferred nap spot, we found a stash of yellow bits of paper, plastic and fabric. This cat had a favorite color!

We set out a small yellow blanket in the house, and he moved it to his nap spot. When he wasn’t drinking enough water, we started putting the water in a yellow bowl, and he stayed well hydrated.

I knew that animals could see colors (contrary to popular myth), but this was the only animal I have ever known to have a favorite color. Until the day he died, he kept his own little spot happily decorated in sunshine yellow.

R.C., Atlanta

DF: This is an interesting account of a cat’s color fixation, for reasons best known to the cat. Feline aesthetics, perhaps!

Cats can see some colors and can tell the difference between red, blue and yellow lights. Also, they are able to distinguish between blues and violets better than between colors near the red end of the spectrum. Recent research has also revealed that they can detect ultraviolet light.

When we match what we know of cats’ multisensory abilities and recent comparative genetic research showing that domestication has done little to temper their wild heritage, we can embrace them knowing that they are, with some breed and individual exceptions, still more wild than domesticated.

Your sister’s cat may have found a way to create, through this game of color-selection, a degree of environmental stimulation for a complex little brain and spirit living in a relatively unstimulating home environment — the social enrichment of friendly dogs notwithstanding.

Michael W. Fox, author of a newsletter and books on animal care, welfare and rights, is a veterinarian with doctoral degrees in medicine and animal behavior. Send letters to animaldocfox@gmail.com or write to him at United Feature Syndicate, 1130 Walnut St., Kansas City, Mo. 64106.

2014 United Feature Syndicate