Your dog's hair grows in a 3-phase cycle. In the anagen phase, the hair does its most rapid growing. Once it has almost reached its full length, it enters a very short catogen phase during which time hair growth is ending. Then it enters its telogen phase when no growth occurs at all and during which shedding occurs. Despite years and years of research, we do not understand what controls this cycle. In some dogs, the first two parts of the cycle last a very long time (over a year), in high-shedders they are much shorter (a month or so). This determines the rate at which your dog sheds. We used to assume that the hair that you find in the comb was mostly from follicles in the telogen (resting)phase. But we now think that this is the hair that is being replace as new hair is formed (Journal Of Investigative Dermatology ). So stimulating hair growth in your dog may actually make the problem worse. We do not understand why the hair loosens up on your pet at that point. But it is probably not because the new hair is forcing the old one out.
That is why breeds that need frequent hair cuts tend to shed less. The most popular of these breeds are poodles, schnauzers, Shih-Tzus, Scotties, Bichons and Airdales, as well as Yorkshire, Carin, Maltese, Silky, Wheaten, Fox, Beldlington and West Highland terriers. Greyhounds are generally low shedders too. Longhaired dogs may appear to shed more, but this is really just an illusion because their long hair strands are easier to notice. The color of your dog's hair also influences how noticeable hair is around the house.
If you adopt a mixed breed dog and shedding is important to you, Adopt one with a curly or long hair coat or one that you know is a cross with one of the low-shed breeds. The trade off that dogs with this type of hair coat need more grooming and suffer more in hot weather.
At a distant time in the past, dogs entered their shed in the spring in response to increasing daylight hours - just as wolves and other wild animals do. But as they slowly evolved into living with us and lost more than their wild nature, they also lost their normal periodic cycles. These cycles are called cercadian rhythms. How they work is poorly understood, but they control all sorts of annual changes from reproduction, mood and hair growth.
We know that they are all in some way related to the pineal gland and probably to the hormone, melatonin as well. While your pet's hair is in the telogen or resting phase, a new hair begins to form below it in the hair follicle. At one time this occurred simultaneously in all the dog's hair follicles, but when they lost their natural circadian rhythm the follicles no longer shed at the same time. This accounts for year-long shedding in our pets. Many dogs still shed the most in the spring and fall. It is the length of the days and not seasonal temperature change that accounts for this.
These arctic breeds have retained this wild shed pattern best. They generally do their shedding in one or two short spurts during the year in the spring and fall.
Hair loss is different from shedding. When a dog sheds, a new hair is growing it the hair follicle to replace it. When a dog suffers from hair loss due to some form of sickness, no new hair grows or it grows very slowly. In another form of hair loss caused by a sluggish thyroid gland, hair is replaced to infrequently and individual hairs stay on the pet so long, that they literally wear out. This is why black coats in dogs with this problem sometimes appear reddish brown. Dogs that have hair loss on areas that rub allot - like their sides, hind legs and tail have this or a similar problem.
pet's hair must be replace on a regular basis for it to have a natural
coat. Hair wears out , so new hairs in anagen must be produced.
The best we can hope for is to synchronize anagen to one or two
short periods of the year as occurred in your pet's wild ancestors.
It appears that the more natural light your pet experiences, the more likely it is to shed in one or two discrete periods. This may not be the case in your pet - but it is worth a try. Seasonal changes in all animals are due to changes in the length of the day, not to changes in the weather.
We know that the Nordic Breeds, that have retained more of the normal seasonal shedding pattern still shed in response to the melatonin levels in their blood. We do not know if other dogs no longer produces enough melatonin in those amounts or if the pet's hair has lost it's ability to respond to melatonin. In certain situations, melatonin administration cures hair loss in Nordic Breeds. The problem is that melatonin levels pulse in the body. So just giving a supplement does not duplicate what naturally occurs. Melatonin supplements for hair loss or shedding have not been given long enough for me to recommend any specific dose.
A good diet minimizes shedding. Be sure the pet food you feed contains adequate levels of protein, fats, vitamins and minerals. Most nationally marketed brands do. But if your pet receives a large portion of it's diet in table scraps, try cutting those down.
The body washes, fatty acid and vitamin sprays you can buy, only manage to moisturize your pet's skin with the oils they contain. They do not help with shedding. The oral coat supplements of vitamins, fatty acids and other nutrients do not help a dog that is receiving a good diet.
We have no real scientific evidence that Omega-3 fatty acid- containing products really reduce shedding. But some people think they do. They seem to have so many other positive benefits to health that you may wish to try them for your pet.
Pets in good general health shed less than those that are not. Anything that makes your pet scratch will increase the amount of hair you find around the house. The most common causes are fleas and allergies.
Brushing your pet frequently with the proper comb will remove the problem of hair around the house. This is the low-tech solution. I find it best if I use a comb which has teeth imbeded in a rubber backing (slicker comb). Many that are sold have the teeth too widely spaced. There is a proper size for each pet.