Dear Daisy Dog: Please tell me the truth about grain-free pet foods. A pet store employee told me they're healthier than diets with grains, but my veterinarian says they're just a marketing gimmick.

Daisy responds: Your veterinarian studied nutrition in vet school and is correct. Veterinary nutritionists agree that grain-free diets offer no special benefits, and no research shows them to be superior.

To understand, let's start with the basics. Food ingredients provide nutrients such as proteins, carbohydrates, fats, vitamins, minerals and water, which are substances needed by the body. So an ingredient, such as a grain, is simply a carrier of nutrients, such as carbohydrates, which the body uses to generate energy.

Grains contain not just carbohydrates, but also vitamins, minerals, fatty acids and protein. Interestingly, grain protein often is easier for dogs to digest than meat protein.

Actually, grain-free diets may be less healthful than grain-containing diets if they substitute starches, such as white potato or tapioca, which provide less fiber and fewer vitamins and minerals than grains.

Some people mistakenly believe dogs are allergic to grains. However, food allergy is uncommon in dogs, and when it occurs, the culprit most often is a meat protein.

So you don't have to change pet food if your dog is doing well on his current diet. If he isn't, ask your veterinarian for a recommendation.

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Dear Christopher Cat: We are moving to Central America in the fall with our cat, Katrina. What do we need to know?

Christopher responds: The Animal and Plant Health Inspection Service (APHIS) of the U.S. Department of Agriculture has a website to help you: www.aphis.usda.gov/aphis/pet-travel.

The APHIS Pet Travel website explains the regulations governing pet travel between states and between the U.S. and other countries. It's easy to determine what's necessary to move Katrina to her new home; simply visit the website, choose your destination country from the drop-down menu and click View Requirements.

The destination country determines what regulations apply to importing an animal into their country. So, just to be sure, contact the consulate of your destination country and your airline to see if any additional requirements apply.

The next step is to accustom Katrina to traveling in her carrier. Start now by feeding her there, and add a fluffy towel or bed cushion to encourage her to sleep there.

Spray Feliway, a comforting pheromone, in her carrier, and take her for rides in the car so she learns to relax during travel.

If she has any medical conditions, your veterinarian can advise you about the additional care she'll need while traveling.

Ask the Vet's Pets appears Friday in the print edition of the Reading Eagle. The animal authors of the column live with Lee Pickett, V.M.D., who practices companion animal medicine. Contact them at www.askthevetspets.com.