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With warmer weather approaching, plenty of pet owners are thinking of getting into shape before hitting the beach. But what about pets? Obesity is a growing problem among both cats and dogs. And much like humans, too many extra pounds can have far-reaching consequences for our animal companions. In this report from the Veterinary News Network, Dr. Jim Humphries discusses the health problems that can occur if your pet is overweight and shares tips on how you can get your pet's weight under control.

Owners who want to better understand their canine companions must recognize that dogs see the world from a different visual perspective. The differences begin with the structure of the eye. We have a good idea what dogs see because we know the make-up of the retina of a dog’s eye.

The retina is the light sensitive portion of the eye. This structure is located in the back of the inside of the eyeball. The retina contains two types of light sensitive cells: rods and cones. Cones provide color perception and detailed sight, while rods detect motion and vision in dim light. Dogs have rod-dominated retinas that allow them to see well in the dark. Along with superior night vision, dogs have better motion visibility than humans have. However, because their retinas’ contain only about one-tenth the concentration of cones that humans have, dogs do not see colors as humans do.

Dogs see like a color-blind human. Many people think that a person who is red/green color blind cannot see any color, but there are variations of color blindness. Most people have vision that is trichromatic (three-color variations). People who are red/green color blind are dichromatic (two color variations). Dogs’ retinas can distinguish two colors. These colors are blue-violet and yellow. Dogs can also differentiate between shades of gray. Dogs are unable to recognize green, yellow, orange, and red.

Colors That Humans See

Colors That Dogs See

Dogs use other cues such as smell, texture, brightness, and position rather than relying solely on color. Seeing-eye dogs, for example, may not distinguish between a green or red stoplight; they look at the brightness and position of the light. This, along with the flow and noise of traffic, tell the dog that it is the right time to cross the street.

How a dog’s eyes are set determines the field of view as well as depth perception. Prey species tend to have eyes located on the sides of their head. This gives the animals an increased field of view and allows them to see approaching predators. Predator species, like humans and dogs, have eyes set close together. Human eyes are set straight forward while dog eyes, depending on the breed, are usually set at a 20 degree angle. This angle increases the field of view and therefore increases the peripheral vision of the dog.

Increased peripheral vision compromises the amount of binocular vision. Binocular vision occurs where the field of view of each eye overlaps. Binocular vision is necessary for depth perception. The wider-set eyes of dogs have less overlap and less binocular vision, thus, less depth perception). Dogs’ depth perception is best when they look straight ahead. This is not an ideal situation, as their nose often interferes. Predators need binocular vision as a survival tool. Binocular vision aids in jumping, leaping, catching, and many other activities fundamental to predators.

In addition to having less binocular vision than humans have, dogs also have less visual acuity. Humans with perfect eyesight are said to have 20/20 vision. This means that we can distinguish letters or objects at a distance of 20 feet. Dogs typically have 20/75 vision. What this means is that they must be 20 feet from an object to see it as well as a human standing 75 feet away. Certain breeds have better visual acuity. Labradors, commonly used as seeing-eye dogs, are bred for better eyesight and may have vision that is closer to 20/20.

If you’re silently standing across the field from your dog, don’t expect him or her to recognize you. He’ll recognize you when you do some sort of motion particular to yourself. He may also recognize your presence by his outstanding sense of smell and/or hearing. Because of the large number of rods in the retina, dogs see moving objects much better than they see stationary objects. Motion sensitivity has been noted as the critical aspect of canine vision. Much of dog behavior deals with posture and appropriateness. Small changes in your body posture mean a lot to your dog. Dog owners need to modify training based on this fact. If you want your dog to perform an action based on a silent cue, we suggest using a wide sweeping hand and arm motion in order to cue your dog.

When dogs go blind, owners often wonder if the dogs’ quality of life has diminished to the point where they are no longer happy. Humans deal well with being blind, and humans are much more dependent on their eyes than are dogs. Blind dogs lead happy lives as long as they are comfortable. The owner may need to make some adjustments in the pet’s environment. Some of these adjustments include fencing the yard, taking leashed walks, and not leaving unusual objects in the dog’s normal pathways. Obviously, most blind dogs cannot navigate stairs very well. When blind dogs are in their normal environment, most people don’t know they are blind.

People are not the only ones at risk for glaucoma and the blindness that can result from it. Veterinarians can now screen your dog or cat for glaucoma with the Tono-pen. The Tono-pen is a state-of-the-art device now available to measure the pressure inside your pet's eye. Previous measuring devices were less accurate, difficult to use and required a large degree of animal restraint. The Tono-pen, however, is quick, easy and reliable. Your pet can be tested in a simple office visit.

Glaucoma refers to an increase in intraocular pressure, which can result in loss of vision. Since glaucoma may affect only one eye initially, most owners will not notice the blindness. Owners may notice that the pet's eye is bulging, red, tearing or squinting. There are now 41 recognized breeds that are predisposed to glaucoma. Because these breeds have a hereditary defect causing the glaucoma, the earlier the disease is detected, the better the chance of maintaining a visual eye. Baseline and annual intraocular testing is available for these breeds. If glaucoma is already known to be in the bloodline, testing should be performed more frequently.

In addition to hereditary causes, glaucoma can result from trauma to the eye, infection inside the eye, and from cataracts and tumors. Cats usually get glaucoma as a result of one of these non-hereditary causes.

Your veterinarian will recommend measurement of intraocular pressure with the Tono-pen if your dog or cat is presented to the office with a red or irritated eye. If increased pressure inside the eye is identified, proper medical or surgical treatment for the glaucoma can then be determined.

Is your dog's breed listed below?

Hepatic lipidosis, also known as fatty liver syndrome, is a common and very serious condition that occurs in fat cats who, for some reason or another, have stopped eating. The disease results from an accumulation of fat in the liver and, if not treated during the early stages, can be deadly. Hepatic lipidosis is treatable and cure rates are good if the cat is presented to a veterinarian during the early stages of the disease.

Why would a fat cat not be eating?

Here are some reasons:

• Bad teeth
• Intestinal blockage
• Stress - examples: Moving into a new home, introducing a new animal into the family, owner goes on vacation
• Hairball
• Illnesses

These are all good reasons why a cat would stop eating. The most common reason for a cat to stop eating is an upper respiratory infection.

Think about it - cats like their food because they enjoy it and are familiar with the smell. So if a cat can't smell its food, it's not going to eat.

The question is: "What would cause a cat to loose its ability to smell food?"

An upper respiratory infection could cause a cat to loose its sense of smell.

Cats get upper respiratory infections all the time - sneezing, runny nose, runny eyes.

So, you have a fat cat that gets the flu and can't smell. Since the cat cannot smell his food, he stops eating. The body is looking for ways to feed itself, and tries to do this by converting stored fat into energy. In order for the fat to be converted into fuel, it must pass through the cat's liver. The liver can't handle this fatty saturation and liver dysfunction ensues. This doesn't happen to thin cats. They don't have enough fat available to mobilize and create this problem.

Many owners do notice that their cat is not eating, but they think, "That's all right, Tiger needs to lose a few pounds." Then, after a week or two without an appetite, they start to worry and finally bring the animal to the veterinarian. If they don't bring their cat in soon enough, he (or she) is a prime candidate for hepatic lipidosis.

Symptoms associated with hepatic lipidosis include loss of appetite, vomiting, depression, weight loss and lethargy. Some cats develop a yellow coloration of the eyes, ears and mouth. This yellow coloration (particularly of the mucus membranes) is jaundice and usually indicates liver disease and/or red blood cell destruction.

The prognosis for cats with hepatic lipidosis is good if treatment is not delayed. The longer that treatment is delayed, the less likely for recovery. Cats that have underlying diseases (cancer, pancreatitis) are less likely to recover.

How would a veterinarian treat a cat with hepatic lipidosis? The veterinarian would probably hospitalize the cat, and among other treatments, feed it through a tube. After your cat has recovered from hepatic lipidosis, or, before your fat cat gets hepatic lipidosis, you should put your cat on a veterinarian-recommended low-calorie diet. Exercise is an important factor in weight loss, so it is important to encourage exercise via catnip or toys. Carefully monitoring your cat's food intake in times of stress (for example, the addition of a new pet) can be crucial in preventing mortality due to hepatic lipidosis.

Preventing obesity is the best way to prevent hepatic lipidosis. Regular meals should be given and free-choice feeding should be avoided. Obese cats should be placed on a special diet food. By slimming Tiger down, you could save him from hepatic lipidosis and other life-threatening diseases related to cat obesity.

For more information on disease prevention, contact a staff member at your veterinary hospital

In general, pets over the age of seven are considered "senior" pets. The following are a few suggestions to help ensure good health to your faithful companion.

As your pet approaches senior status, your veterinarian may recommend basic blood and urine tests as a baseline for measuring future changes. Regular blood testing can help identify diseases in their earliest and most treatable stages.

Note changes in your pet’s behavior or appearance. Treat simple medical problems, such as incessant ear scratching, immediately. A trip to the veterinarian can get problems under control early, before they become major problems requiring more extensive treatment.

Switch to a quality senior food that provides enhanced levels of key nutrients

Ask your veterinarian about a dental checkup and teeth cleaning. Follow the cleaning with recommended dental care at home.

Provide moderate exercise. This will deter anxiety-related behavior problems, help with weight control and keep muscles toned.

Talk with your veterinarian if your dog or cat tires easily or has trouble breathing.

Groom your senior pet at least once a week. Check for lumps, sores, parasites and foul-smelling ears or discharge. Older pets may need to he bathed with medicated or moisturizing shampoo.

Maintain a familiar routine and environment to minimize stress.

If your pet has not been spayed or neutered, ask your veterinarian about having this done. These procedures reduce the likelihood of mammary or prostate gland tumors.

As your veterinarian about a Senior Pet Health Examination. He or she will examine your pet and offer suggestions for maintaining an excellent quality of life.