Q -- Why does my vet insist on doing a rectal exam on my male intact dog every year? The dog really hates to have it done. She tells me that it is to evaluate the animal's prostate gland, but is prostate disease really that common in dogs?
A -- Your veterinarian should be commended for doing a thorough examination on your dog. Although your dog may find this procedure somewhat uncomfortable, it is an important part of an older dog's yearly physical examination. Prostate disease is quite common in intact male dogs. A study done using beagles found that by six years of age, 80 percent of the dogs studied had prostate enlargement. By the age of 9 this number jumps to an amazing 95 percent. While not always equal to disease, this enlargement should be monitored. The constant exposure of the dog's prostate gland to testosterone from the testes causes it to enlarge over time. Neutered dogs do not experience this problem. Some dogs will develop cysts within their prostate. Others develop prostate infections, abscesses, or tumors. Rectal exam can determine the size, shape and location of your dog's prostate. If prostate disease is suspected, your veterinarian may suggest that a biopsy, radiographs or an ultrasound be performed.
D. Jeff Pollard, DVM
Dogs see some colors
Q -- Are dogs color-blind? I've read that they see everything in black, gray and white, but my husband thinks that dogs can see some colors. Who is right?
A -- Studies of the canine retina have found that cones, color sensitive photoreceptors, do exist, just fewer than found in human eyes. We know that dogs can perceive color, we just don't know how it is perceived. Dogs appear to be unable to see color in the blue-green region. Light in that wavelength probably appears colorless or gray to them. Dogs don't seem to be able to tell the difference between colors in the red, orange or green color range. A dog's vision is probably similar to the vision of a red-green color-blind person. Dogs appear to surpass humans in their ability to differentiate between shades of gray, though.
D. Jeff Pollard, DVM