DEAR DR. FOX: For 2 1/2 years, my dog weighed 49 pounds and took heartworm medicine for dogs weighing from 25 to 50 pounds (Sentinel once-a-month tablets). Last week, she weighed 51 pounds, and I was told to increase to the 50 to 100-pound tablet. This seems like overkill, but the vet made a big deal out of it. Though she was covered just fine at 49 pounds, she's no longer safe since she gained 2 pounds.

What are your thoughts on this? -- M.K., Virginia Beach, Va.

DEAR M.K.: You raise an important question. I had the same conundrum with one of my own dogs and decided to feed her less and exercise her more when she crossed over from a svelte 47 to 52 pounds, which meant I could keep her on the smaller dose of Heartguard's ivermectin.

It is important in all states where there is a winter kill of mosquitoes to take dogs off this preventive medication and have a blood titer test done to make sure they are clear before resuming medication the next spring.

There are concerns that the heartworm parasite is developing drug resistance in some states, especially in the Mississippi River delta, so extra vigilance and not missing the monthly preventive medication are called for at this time.

DEAR DR. FOX: Do you recommend deworming cats? One of the three from a litter, now 9 months old, vomits after every meal. The other two are fine. -- J.V., Winston-Salem, N.C.

DEAR J.V.: Please avoid the temptation to make your own veterinary diagnosis, and take your cat to see a veterinarian if you believe your cat has worms because you have actually seen them. Cats and dogs who sometimes vomit or have loose stools are too often given over-the-counter worming medications by their owners, which, more often than not, cause more harm than good and are a waste of money because worms were not a problem. But this is not to ignore the fact that most kittens and puppies need worming with the right medication once the kind of worms they have are identified.

Similarly, people will buy various flea sprays, drops and pills whenever they see their pet scratching, making a wrong diagnosis -- cats and dogs scratch themselves intensely for reasons other than fleas -- even with fatal consequences for cats when given anti-flea preparations meant only for dogs.

YOUR END-OF-YEAR DONATIONS: AVOIDING CORRUPT CHARITIES

There has been much talk in the news about various charities, designated as nonprofit organizations, from those claiming to help war veterans to international disaster relief, that prove to be scams with little or no funds ever going to help the designated causes. Always make sure your donations are tax-deductible and go to a registered 501(c)(3) charity. For some guidance in this domain, visit charitywatch.org and charitynavigator.org. Also find some links to reputable nonprofit organizations on my website, DrFoxVet.com.

When it comes to animal and environmental protection organizations soliciting your support, some of the large ones are already well-funded by corporations and their spin-off charity branches or foundations. They may be limited in their effectiveness by conflicts of interest and by the need to maintain high executive salaries and slush fund travel expenses and other perks, some playing shell games with their accounting and accountability.

Remember, small is beautiful, and small, local groups and chapters of reputable larger nonprofits (such as the Audubon Society) are easier to support if you want to monitor your donations and not just send out some conscience money to feel good. Small organizations include your local animal shelter and humane society -- not to be confused with the Humane Society of the United States -- and wildlife rehabilitation and environmental education centers. Some larger nonprofits, such as the Animal Welfare Institute, Union of Concerned Scientists and Earth Island Institute, are reliably transparent. One must be especially cautious with those soliciting funds to help nonprofit organizations abroad. Find out if your donations are tax deductible and what percentage goes to actually help rather than paying for overhead expenses.

(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 DrFoxVet.com.)

DEAR DR. FOX: I enjoy your articles in my local newspaper, and one in particular caught my attention.

I will try to make this as brief as possible:

I owned two cats, both indoor-only. One cat was domesticated when I got her; the other was a feral kitten someone found and gave to me. She was still young enough to tame, but even after age 4, she was still not very trusting.

Both cats got their yearly exam and shots, including one for feline leukemia. A few months after Lovely got her annual shots, I noticed that she was limping. I examined her right leg and found a large mass on her upper shoulder -- she has long fur, so it wasn't noticeable except by feeling. I took her to my vet, who did a needle biopsy and gave me some pain meds for her. The next day, after giving her the meds, her whole personality changed -- she hid all day and came out only at night.

The lump was cancerous, and her leg would have to be amputated. Trying to get her to the surgeon that morning was terrible -- she fought and tried to bite me. Finally, we were able to get her there. The surgeon told us that her personality change may be permanent and the stress of losing the leg would possibly make it worse. He also mentioned that the leukemia shot may have caused the cancer and that it may have spread to other organs. We made the painful decision to put her down.

After asking another vet and my own vet, they admitted that the leukemia shot would, in some cases, cause cancer at the site of the injection in the upper shoulder.

Please advise other owners of indoor cats that this shot is not necessary. When my other cat, Lady, was due for her shots, my vet, after all we went through, was still going to give her that shot; I said, "No!" -- A.M., Naples, Fla.

DEAR A.M.: According to veterinary literature, cancer (specifically fibrosarcoma) developing at the vaccination site is extremely rare, but it does occur. As a precaution, until nasal or oral vaccines are developed, the proper vaccination protocol for cats is to inject the vaccine as low down as possible on a hind leg. Amputation is then more feasible and less crippling than having to remove the cat's entire shoulder area and foreleg, as was the case with your poor cat.

I am surprised that your cat was vaccinated in the shoulder region. Certainly, the pain would have changed her personality. Also, the pain medication could have made her more fearful, as could the traumatic trip to see the veterinarian.

Send this reply to the veterinarian to change the vaccination protocol: inject a lower hind leg; do not prescribe feline leukemia vaccinations for indoor cats; separate giving rabies vaccinations from other vaccines for which blood titers can be conducted to determine if they are really needed.

A new protocol, which was suggested several years ago, of vaccinating in the tip of the cat's tail has been confirmed as being effective and safe by Dr. Julie Levy and her team at the University of Florida School of Veterinary Medicine.

DEAR DR. FOX: Amos is the sweetest, most loving cat we have ever had. He is intuitive and answers us when we talk to him, and he stays with us constantly. We adopted him in 2007, and he's now about 10 or 11 years old. He is a real joy, the center of our family and is admittedly spoiled rotten. He has had no real physical issues except with some of his teeth that had to be pulled about two years ago.

We were wondering: Why does he get up every morning at exactly 4:20 a.m. without fail? Daylight saving time does not seem to throw him off. He starts to meow up and down the hallway, then jumps on our bed to complete his mission. My husband, like any dedicated pet owner would do, gets up and plays with him, feeds him and then he promptly takes a good old-fashioned "cat nap." We have tried everything, such as closing the bedroom door, playing with him late at night, making sure he has kibble and water, but he is relentless until we get up.

We read in your column that some cats are calling for companionship from other cats when they cry out. Could this be the case, and is there anything we can do? He is such a joy and we get a kick out of his habits, but we could use a little more sleep. -- F. & P.S., Winchester, Va.

DEAR F. & P.S.: There's a time clock in your cat's brain that you clearly cannot reset. You may have found the only solution other than trying to ignore him.

When his brain says it's early to rise, it is telling him to go out to hunt and interact with other cats on their predawn roaming in the wild.

Adopting a younger cat may be the best solution. Providing your cat with a substitute for your husband to play with and race through the house while you both enjoy a less interrupted sleep could help all parites. Check my website, DrFoxVet.com, for the important steps you are advised to take when introducing a new cat into your home.

(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 DrFoxVet.com.)

DEAR DR. FOX: I need some advice about our aging cat's health care: We adopted her when she was 4 years old, and she had dental problems. She had three teeth extracted, and the vet suggested Hill's Prescription t/d Feline Dental Health to prevent further tooth loss. She has always had a nasal wheeze but has not seemed bothered by it. In the last two or three years, she has developed more heavy breathing, particularly when she sleeps -- in other words, she snores. Sometimes she sits just staring into space like she is in a trance.

The vet has not found lung or cardiac problems. She has some arthritis, and the vet suggested glucosamine injections instead of steroids/cortisone. We have not proceeded with the injections.

Can I change her diet to help with the breathing/snoring problem and the arthritis? I have read a little about raw diets, but I've not attempted one. Would it be a good idea to get some raw meat from the grocery store?

We would welcome any advice you may have, despite the fact that we can't bring her to see you. -- F. & R.G., Leesburg, Va.

DEAR F. & R.G.: The tooth loss problem, so prevalent in cats, may be due to excessive amounts of vitamin D3, added by pet food manufacturers to cat foods. I will be writing more about this in a future column.

Your cat's breathing problems could be caused by several factors, considering her age. Her trancelike staring could be associated with age-related dementia and Alzheimer's disease. What may really help her, even at this late stage in life, is a grain- and soy-free diet, especially avoiding corn meal, corn gluten and other corn ingredients. Good-quality fish oil, canned sardines and organic butter are sources of omega-3 fatty acids that should benefit your cat significantly. Give her just a drop or two of fish oil initially, working up to 1/2 teaspoon daily, along with the same amount of either sardines or butter.

DEAR DR. FOX: This is an update to a question I sent you about my "granddog." She was about to have a biopsy because she was thought to have osteosarcoma in one of her hind legs. As it turned out, her biopsy showed that she has chondrosarcoma rather than osteosarcoma. Apparently, there was no evidence of metastasis. Her amputation is scheduled for tomorrow.

My question remains the same, but I wanted you to be able to take the new diagnosis into account: Are there supplements or treatments to suppress any possible metastatic tumors if there are undetected ones and increase her chances of survival? I guess I should also ask if you have any special dietary recommendations for a cancer patient. I know you recommend home-cooked food in general. My son and his wife have two children and very demanding jobs, so I don't see this happening, but maybe you could still make some suggestions. -- J.S., Rockville, Md.

DEAR J.S.: With no evident spread of the cancer to other parts of the body, the dog's cancer prognosis is not without some degree of hope. But there could still be one or more undetected metastases, so I share your concerns.

There are some special diets (including grain-free, raw food and fruit and vegetable formulations) that do seem to make a difference and which I have detailed in earlier columns. These are archived on my website, DrFoxVet.com, and can be accessed by entering appropriate words like "dog, cancer, diet" in the Question Box.

I am impressed by some reports about the cancer-fighting benefits of various mushrooms and herbs, such as turmeric. One of our beloved dogs had the same hind leg amputation for chondrosarcoma. She was only 6 years old and with our post-surgical assistance and devotion, coupled with daily massage therapy, quickly adapted to enjoying life on three legs.

(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 DrFoxVet.com.)