Swimming is a great exercise for dogs, and can also be the perfect relief from summer heat.  Whether you are out on your boat or simply letting it have a dip in the pool, there are many safety precautions pet owners should take while swimming with their dogs. First and foremost, make sure that your dog can swim.  Most dogs can be taught to swim but others are not made for it or are simply too afraid.  Other dangers are less about the dog, and more about the place they're swimming.  For example, In the summer of 2007, at least three dogs in Minnesota died after swimming in lakes that contained blue-green algae. In Michigan, a nine-month old border collie named Vita died shortly after swimming in a pond with the algae.

"Had I ever heard of the danger of blue-green algae, I never would have allowed my dogs to swim in that or any other pond; I would have bought a pool,'' Vita's owner said in a newspaper interview.

Health officials have known about blue-green algae for years, but there is little documentation regarding pets. "There are not many cases written up,'' said Robert Poppenga, DVM, PhD, of the California Animal Health and Food Safety Toxicology Laboratory at the University of California School of Veterinary Medicine, Davis. "They happen. Owners may not see the animal ingest the material, so they may not make the connection. However, now there is more attention about the harmful effects of algae blooms in people, so it's beginning to transfer to dogs.''

Though swimming is great exercise for dogs, he says, each body of water where pets can cavort - ponds and lakes, pools, or ocean - has its own dangers. Pet owners can minimize risk by knowing what they are and how to prevent or avoid them.

Ponds and lakes

Other than the blue-green algae, ponds and lakes can be good places for dogs to swim because they don't have tides or currents, but owners should watch the water carefully, no matter how clean it looks.

For example, many parks, golf courses or subdivisions that have lakes or ponds treat them with chemicals to prevent algae. The chemicals can cause skin irritation. "Chemicals,'' Poppenga said, "can cause liver damage, and in some cases, neurologic damage. If you suspect something along these lines, take the animal to a vet immediately.''

Also, ponds and lakes in the country may contain materials toxic to dogs such as fertilizers, pesticides or herbicides that are "run-off'' from area farms. Larger lakes where motor-boating is allowed might have higher concentrations of motor oil. If you are on a boat and your dog jumps from it, make sure there is a logical way to get the dog back in.

Never let a dog drink from a pond or lake, so take fresh water for drinking as well as for bathing the dog after a swim.  If you fear that your dog has ingested bad water or has swam in water that may be toxic, call for help immediately.

Swimming pool safety

The most important thing about pools, says Paula Patton, professional dog trainer at The Gray Dog Lodge in Lenoir City, Tenn., is that they have steps and dogs should know where they are. "Dogs should never be allowed to swim alone,'' she said. "When pools are not in use, they should be covered. But most importantly, your pet should know how to get out of the pool without struggle.''

She also recommends the following:

• Monitor your pet to make sure the chlorinated water in the pool is not irritating. Watch especially your pet's eyes for irritation.
• Don't let your pet drink the chlorinated water.
• After a dip in the pool, most pets should be hosed or bathed to remove chlorine that can dry the coat and be ingested when the pet is grooming.

Swimming in the Ocean

 Any dog that goes swimming in the ocean can be pulled under by strong tides and undercurrents, said Alison White, a pet hydrotherapist who works in Oceanside, Calif. "I have dogs that swim in the ocean and I am very alert,'' she said. "A life jacket is essential. Also, I don't let my dogs go out too far. Sometime dogs are too focused on finding a ball that's been thrown. They become so obsessed with the ball that they get pulled out and then you have to go out after them.''

Her other recommendations:

• Scan the water for jellyfish. Be aware of sea lice that can cause itchy red bumps on dogs.
• Do not let dogs become overly tired in the water. Older dogs lack the endurance they once had.
• Do not allow the dog to drink sea water because the salt can cause sickness. Salt can be irritating to paws and skin, too.
• Rinse salt water and sand from your dog's coat after swimming.
• Always clean and dry ears after a swim. Water that remains in ears, especially from a dirty lake, can result in a bacterial ear infection.

An easy way to skirt a lot of the danger of swimming is to purchase a " kiddie pool'' for pets. Sprinklers and kiddie pools are effective and safer for dogs that are older or impaired, or for breeds that don't swim. Water from the hose is sufficient, and chlorine isn't necessary. Wading or splashing is fun for dogs, and has the same cooling effect as a large body of water.