DEAR DR. FOX: I hope you can give us some advice, as we are quite confused and frightened for Simba, our beloved 8-year-old Chihuahua-Pomeranian whom we adopted from a shelter when he was only weeks old. He has always been in perfect health, and he is very fit, active and adorable. My mother adopted him a week before her unexpected death. We took him into our home and have loved him ever since. He is our connection to her.

During a routine checkup a few weeks ago, our veterinarian diagnosed a significant heart murmur and took an X-ray that revealed an enlarged heart on the left side. He recommended that we see a cardiologist, which we did immediately. Simba is asymptomatic, but an electrocardiogram revealed that he has moderate degenerative valvular disease with moderate left atrial dilation and mild left ventricular dilation.

We would like your opinion on the medications that the cardiologist has prescribed for Simba: enalapril and spironolactone. Simba has always been fed premium dog food, starting with Innova when he was a puppy and now Before Grain (salmon). We would like to switch to your food protocol, but we need more clarification on how to prepare it correctly. I am so frightened of giving him something wrong. His primary vet prescribed a cardiac nutrient supplement, but we won't start that regimen until we get him on the medications at full dose.

Could you give us your opinion as to whether we are giving him the proper medication? I trust the cardiologist, but we are not big medicine people, and I would rather our dog not have to endure side effects if the medication will not help him.

Simba weighs 10.3 pounds. We free-feed him and he self-regulates -- his weight has always been between 10.3 and 10.8 pounds. He walks three to four times a day, is not coughing and is as hyper as his breed would indicate. We are very concerned about him. -- C.S., Kansas City, Mo.

DEAR C.S.: The kind of heart disease affecting your dog is relatively common in many toy breeds. The treatment protocol and choice of drugs for this problem are eminently appropriate, in my opinion. I would not advise you to change your dog's diet at this time -- salmon is good, but steer toward a low-salt intake. If magnesium and coenzyme Q10 are not in the cardiac nutrient supplement, discuss their inclusion along with a few drops of fish oil.

Your veterinarian is well informed, and I would follow his advice. He needs to take blood samples to monitor Simba's condition and determine if and when the levels of medication need to be adjusted. With careful monitoring, blood tests and general checkups, your dog should enjoy a good quality of life with minimal, if any, harmful side effects from these medications. They will help stop further degenerative changes in your dog's heart -- but not reverse them -- and help maintain normal heart function and circulation.

DEAR DR. FOX: Last year was the worst for fleas for our cats. Frontline has always controlled fleas in the past, but not last summer. We used Frontline as directed, plus flea powder (which we also applied to our rugs), but we still got fleas.

A friend recommended Natural Defense, but is it safe for cats? It contains peppermint oil, cinnamon oil, lemongrass oil, clove oil, thyme and vanilla. If Natural Defense is not safe for cats, what do you recommend? Can you suggest something else?

My cats do go outdoors a little, and we have wild raccoons, opossums and squirrels outside. -- P.C.L., Matawan, N.J.

DEAR P.C.L.: By all accounts, fleas were a major problem last summer. I am not alone in contending that this epidemic is one of the many consequences of climate change.

One major concern with increasing populations of noxious, biting insects is that the bugs can develop resistance to insecticides. Ticks spreading Lyme disease to humans, dogs, cats and other animals is just the tip of this iceberg.

The best medicine is prevention rather than reliance on insecticides that can have adverse health and environmental consequences. One integrative approach to flea and tick control is available on my website, www.twobitdog.com/DrFox. It is especially important to not allow cats to roam freely outdoors, where they will be magnets for fleas. Getting them used to 1/2 to 1 teaspoon of brewer's yeast in their food every day, along with a daily flea-combing inspection, can help. Safe insecticides for in-home use include Perma-Guard and Fleabusters.

I do not advise using insect repellant products that contain essential oils such as peppermint and lemongrass on cats, but they are generally safe and effective on dogs.

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

Visit Dr. Fox's website at www.twobitdog.com/DrFox.)

DEAR DR. FOX: I have a 2-year-old neutered male tabby cat who has a bad yowling problem, and I don't know how to fix it.

I feed him twice daily, as that was the way the people fed him before I got him. I have had him for a year. I feed him 1/2 cup dry food (Purina One) morning and night. If I put the food out at once, he eats it all. Then, when evening comes, he thinks he needs more. He will sometimes throw up because he has eaten too much.

He yowls loudly if I don't feed him the minute I step out of bed and continues until I feed him. He does the same thing at about 9 p.m., though I try to make him wait until 10.

He is a very lovable cat, and he loves to sit on my lap and cuddle. He does not cry except when he wants food.

I would like to know how to break him of the yowling problem or if I just have to deal with it. I would like to be able to put all the food out at once, as sometimes I go away for a few days, and I have to have someone come feed him. -- S.M., Maryland Heights, Mo.

DEAR S.M.: I think your main problem is your feeding schedule, but you might not be feeding him enough. He cries because he is ravenous! Feeding twice a day is OK for dogs, but four to six times a day is better for cats. Feed him smaller portions, and weigh him to check if you are giving him too much or too little.

Some people complain because their cats never "speak." My first cat, a Siamese named Igor, would yowl for attention and when he was hungry. My solution was to talk back, play with him and take him for walks in a harness on a leash.

Your cat may be much happier with a companion cat, so consider a healthy, young neutered male or spayed female from your local shelter. Check my website, www.twobitdog.com/DrFox, for the best steps to take to introduce a new cat -- and for some better brands of cat food.

DEAR DR. FOX: I have two small dogs. I feed them dry food (Solid Gold Just a Wee Bit) in the morning and canned food (Blue Buffalo) in the evening. I would rather make their food for the evening feeding.

Can you please provide a recipe and advise me of any supplements they should be getting. They are my babies, and I want to do good for them. They love carrots and apples, so I try to provide these often. -- A.L., Brick, N.J.

DEAR A.L.: I receive many requests for my basic dog and cat food recipes. Many of my readers do not have access to a computer and my website, so I have published the recipes in my book, "Not Fit for a Dog: The Truth About Manufactured Cat and Dog Food." The book has details about supplements and the ingredients in many prepared pet foods owners should avoid.

As a treat, here is my basic dog food recipe:

1 pound lean hamburger, ground lamb or mutton; one whole chicken; or half a small turkey (all raw)

2 cups uncooked whole-grain rice (or barley, rolled oats or pasta noodles)

Pinch of salt

1 tablespoon vegetable oil (or flaxseed oil* or safflower oil)

1 tablespoon organic butter

1 tablespoon wheat germ

1 tablespoon apple cider vinegar

1 teaspoon brewer's yeast

1 tablespoon calcium carbonate, calcium citrate, lactate or human-grade bone meal

*If you're using flaxseed oil, add it after the cooked food has cooled to room temperature.

Combine all the above ingredients. Add enough water to cover ingredients. Simmer, stir and add more water as needed until cooked. Debone the chicken parts, but do not feed your dog the cooked bones since they can splinter and cause internal injury. While the stew is still very hot, mix in a cup of raw, grated carrots, sweet potatoes or yams. The recipe should be thick enough to be molded into patties -- you can add oat bran, rice or buckwheat flour to help thicken.

For a 30-pound dog, serve 1 cup of this recipe twice daily. Freeze the rest. You can even serve the patties frozen so your dog can gnaw on them in hot weather.

For dogs less than 30 pounds and for overweight and less-active dogs, use only 1 cup of uncooked rice in the recipe.

Transition your dog onto this new diet gradually. Mix increasing amounts of your dog's new food with decreasing amounts of the old food over a seven-day period to enable adaptation and avoid possible digestive upset. For variation, you can use cottage cheese, well-cooked lentils, garbanzo beans, lima beans or a dozen organic eggs as meat alternatives. (Note: Some dogs are allergic or hypersensitive to some foods, especially soy, beef, eggs, wheat and dairy products.)

Don't forget: Lightly cooked calf and beef liver, heart and kidneys are good sources of animal protein and other essential nutrients. All pet food ingredients, ideally, should be organically certified.

Give your dog a daily multivitamin and mutimineral supplement like Pfizer's Pet Tabs. You can also give your dog half of a human one-a-day supplement equivalent crushed up in the food.

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

Visit Dr. Fox's website at www.twobitdog.com/DrFox.)

DEAR DR. FOX: Two years ago, I adopted a beautiful male snowshoe cat from the animal shelter. He is very sweet, natural and content to be with me. But in all this time, I have never heard or felt him purr. I've had cats my entire life, and I have never known one not to be able to purr.

Do you have any explanation for this? He's 4 years old. -- P.G., Virginia Beach, Va.

DEAR P.G.: There is no scientific answer to your question, only educated guesses about genetics and individual differences. Many readers will attest to the fact that their cats never purr or meow. Some silent cats become vocal after a vocal cat in the home passes on.

Fear is a significant inhibitor of purring. The word "copycat" is appropriate -- cats learn from one another, so being separated from other cats at a young age might account for some cats' vocal sounds not being triggered.

Try brushing your cat, and learn some massage therapy to help induce deep relaxation, which I've detailed in my book, "The Healing Touch for Cats." Hearing harp music or Gregorian chants can make cats relax and might get yours into a purring mood.

While cats may purr to relax and convey friendly intentions, one scientific theory holds that the vocal vibrations may influence bone density and help prevent osteoporosis. My view is that since purring may involve circular breathing to create an almost-continuous sound -- a trick some musicians employ, as I do when playing a didgeridoo -- the cats may be inducing a meditative or altered state of consciousness.

DEAR DR. FOX: We adopted a wonderful 2-year-old shelter dog last summer, but he has one bad habit we need your advice on: He eats his stool. We've been told it's not uncommon, won't harm him and he'll probably outgrow it.

But the problem is worse because we have three other dogs, and he wants theirs too. Our vet gave us For-Bid to add to all the dogs' food, but it didn't work. We tried Stool-No! tablets, pepper on the piles and scolding and shaking coins in a can when we catch him in the act. We have to go into the yard with him and follow him around now.

Out in the cold last night, walking around with our flashlight, we started wondering what Dr. Fox would do. Since it's not harmful, should we just relax, let him out unsupervised and try to not think about what is happening?

We walk our dogs every morning until they go, and we pick that up, but the rest of the time requires watching him closely. We used to be able to let our dogs in and out whenever they wanted.

Also, he poops about four times a day, which seems high. Is there a food or diet you recommend that might help with that? -- B.B., St. Louis

DEAR B.B.: I receive many letters from dog owners who, like you, have a stool-eating (coprophagic) dog. Go to my website, www.twobitdog.com/DrFox, and check the archives for various answers and solutions to treating this problem.

This obnoxious activity has psychological and physical causes. The former is linked with dogs being caged or crated for long periods of time and, out of boredom or desire to keep their "den" clean, they engage in coprophagy. The habit can persist even after dogs are provided normal living spaces and outdoor activity -- which may be why he cleans up the other dogs' poop. Try using a muzzle when he's out in the yard with your other dogs; it may break his habit after a few weeks.

Possible physical reasons include dietary or digestive issues. Many dogs show improvement when given brewer's yeast (1 teaspoon per 30 pounds of body weight) in their food, plus 1 tablespoon of probiotic-rich yogurt or kefir. Many dog foods are high in cereals and fiber, which can mean large-volume feces and frequent evacuations, so you may want to transition all your dogs to canned food or low-fiber dry food -- or you can try my home-prepared recipe.

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

Visit Dr. Fox's website at www.twobitdog.com/DrFox.)