Dog coat

Domestic dogs exhibit diverse coat colours and patterns. In many mammals, different colour patterns are the result of the regulation of the Agouti gene, which can cause hair follicles to switch from making black or brown pigments to yellow or nearly white pigments. The most common coat pattern found in modern wolves is agouti, in which the upperside of the body has banded hairs and the underside exhibits lighter shading. The colour yellow is dominant to the colour black and is found in dogs across much of the world and the dingo in Australia. Research has found that tameness brings associated physical changes, including coat colouring and patterning. Domestic dogs often display the remnants of countershading, a common natural camouflage pattern. The basic principle of countershading is when the animal is lit from above, shadows will be cast on the ventral side of the body. These shadows could provide a predator or prey with visual cues relating to the movement of the animal. By being lighter colored on the ventral side of the body, an animal can counteract this, and thereby fool the predator or prey. An alternative explanation is that the dorsal and ventral sides of an animal experience different selection pressures (from the need to blend into different backgrounds when viewed from above and below) resulting in differing coloration. ==Nomenclature of colours and patterns==

Colors The same colour may be referred to differently in different breeds. Likewise, a same term may mean different colourations in different breeds. Brown, chocolate, liver Brown, chocolate and liver are the most common terms used to refer to the bb-dilution of black pigment to a dark brown. Depending on breed and exact shade, terms such as mahogany, midtone brown, grey-brown, blackish brown are used. Sedge and deadgrass are used to describe the desired Chesapeake Bay Retriever color that resembles "that of its working surroundings" as closely as possible. File:Chesapeake Bay Retriever1.jpg|Brown Chesapeake Bay Retriever File:Hilu the Australian Kelpie dog.jpg|Red Australian Kelpie File:Chocolate Labrador Retrievers pair.jpg|Dark and light chocolate Labrador Retrievers Red Red refers to reddish shades of orange, brown, and tan. Terms used include orange, red-gold, cinnamon, tan, and ruby. Genetically a dog called red is usually a clear sable (with little to no eumelanin tipping on hairs) or a ruddy recessive yellow. In some breeds, "red" refers to what would usually be called brown, chocolate, or liver. A "red merle" is always a liver-based merle. In Australian Cattle Dogs, "red" stands for a densely ticked liver-based colouration with an overall red-grey appearance. File:Seter irlandzki profil 5o899.jpg|Red Irish Setter File:01 Chow Chow.jpg|Red Chow Chow File:Owning the back step (3641313887).jpg|Red Standard Poodle File:Ariel Cavalier King Charles Spaniel.jpg|Ruby Cavalier King Charles Spaniel File:Australian Cattle Dog red.JPG|Red Australian Cattle Dog File:A Shiba Inu.jpg|Red Shiba Inu File:Basset Fauve de Bretagne portrait.jpg|Red Basset Fauve de Bretagne File:Cocker spaniel angielski zlotyy.jpg|Red Cocker Spaniel File:Vizsla-profile.jpg|Vizsla Gold and yellow Gold refers specifically to a rich reddish-yellow and its variants, whereas yellow can refer to any shade of yellow and tan. Terms used include yellow-gold, lion-colored, fawn, apricot, wheaten, tawny, straw, yellow-red, mustard, sandy, honey, blond, and lemon. Dogs called golden or yellow tend to be recessive yellow, but can also be sable. File:Agility Poodle.jpg|Apricot Poodle File:3 Golden Retrievers in the water.jpg|Dark Golden Retrievers File:Stretched Dachshund.jpg|Yellow Dachshund File:YellowLabradorLooking.jpg|Yellow Labrador Retriever File:Golden retriever.jpg|Dark Golden Golden Retriever File:Milù 050.JPG|Orange Pomeranian (dog) File:Zazu the dog on Lion's Head mountain 24.jpg|Yellow mixed breed of unknown parentage Cream Cream refers to a pale yellowish or tannish colour which can be almost white. File:Poodle, white standard 01.jpg|Pale cream Standard Poodle File:FrenchBulldog.jpg|Cream French Bulldog File:Yuki and Branca - Japanese Akita.jpg|Cream Akita Fawn Fawn typically refers to a yellow, tan, light brown, or cream dog that has a dark melanistic mask. With Weimaraners, fawn refers to their typical brownish grey colouration that with other breeds is usually called lilac. File:Pug 600.jpg|Silver Fawn Pug File:Westgort Anticipation.JPG|Fawn English Mastiff File:Malinois puppy.JPG|Fawn Belgian Shepherd Malinois with breed-typical extended [dark] mask File:Male fawn Boxer undocked.jpg|Fawn Boxer File:HuntHillBoerboelsGunston1.jpeg|Fawn Boerboel Black Black is a pure black that can get grizzled as the dog ages, or have a tendency to gain a brownish cast when exposed to the elements. File:Newfoundland dog.jpg|Newfoundland File:Black_labrador_on_green_grass.png|Elderly black Labrador Retriever with age-related grey hairs on head and feet File:Schipperke image 001.jpg|Black Schipperke File:Crni Patuljasti šnaucer.jpg|Black Schnauzer Blue Blue is a cool-toned, metallic grey. It typically means a d/d dilution of black pigment, a grey colouration that is grey from birth, but has a wide range of breed-specific meanings. In Kerry Blue Terriers, Poodles, and Bearded Collies, "blue" refers to colouration that is black at birth and progressively greys out as the dog matures. In Australian Shepherds, Rough Collies, and Shetland Sheepdogs, blue means a blue (black-based) merle. In Australian Silky Terriers, blue means a saddle-type black and tan pattern, where the black parts of the coat progressively fade to a steel grey as the dog matures and in Australian Cattle Dogs, blue stands for a densely ticked black-based colouration with an overall blue-grey appearance. File:Standing_Neo.jpg|Blue Neapolitan Mastiff File:PastorBelga-AlemaoDSC 2788.jpg|Blue mixed-breed dog File:Australian Silky Terrier Karlyermai Classic Touch.jpg|Blue Australian Silky Terrier File:Australian blue cattle dog 04.JPG|Blue Australian Cattle Dog Grey Grey simply means a grey colouration of any shade. It can be used as an alternative synonym of blue, but tends to mean some other type of grey than the d/d dilution of black. Synonyms include silver, pepper, grizzle, slate, blue-black grey, black and silver, steel. Greys of a dusty or brownish cast are often lilac, a d/d dilution of liver, and this colouration does not have much of a commonly recognised name. Across various breeds, it is called lavender, silver-fawn, isabella, fawn, café au lait or silver beige. In Poodles, a blue is a very slowly fading, very dark steel grey, whereas a silver is a quicker to clear, much lighter grey that can range from a pale platinum to a steel grey. Both are black at birth with minimal markings to indicate future change. Similarly, café au lait is a slower and darker and silver beige a quicker and lighter progressively greying brown, i.e. liver. File:Waterloo 027 4x6.JPG|Lighter and darker fawn Weimaraners File:Miniature Schnauzer 2.jpg|Silver Miniature Schnauzer File:Spooky (8359203146).jpg|Young Silver Standard Poodle in the earliest stages of graying out File:Doberman Fawn 001.jpg|Isabella/fawn Dobermann White White: Such a light cream that it is seen and described as pure white, making them distinct from albino dogs. A white dog, as opposed to an albino one, has dark pigment around the eye rims and nose, often coupled with dark-colored eyes. There is often some coat identifiable as cream between the dog's shoulder blades. Extreme piebald dogs can also appear all white, but are caused by a separate factor. File:American Eskimo Dog.jpg|White American Eskimo Dog File:Bichon Frise 600.jpg|White Bichon Frisé File:Maltese at NZ National Dog Show.jpg|White Maltese dog File:Coton de Tulear puppy.jpg|White Coton de Tulear puppy File:Bruno spitz japones.jpg|White Japanese Spitz File:Samoyed Image 001.jpg|Samoyed dog File:Westhighlandterrier.jpg|West Highland White Terrier Patterns The same pattern may be referred to differently in different breeds. == Length and texture ==

Bearded Collie (top, with facial furnishings) vs border collie (bottom, no furnishings) Dogs demonstrate an enormous diversity in coat length and texture, from the very short and smooth coat seen in the vizslas, to the wiry coat of a Scottish Terrier and the corded coat of the Puli and the Komondor. Generally, coats vary along three categories: length (long vs. short), texture (curly vs. straight), and coarseness (wire-haired vs. non-wire). These three categories all interact with one another; thus, one can see a short, curly, and wired coat in the Wirehaired Pointing Griffon, and a long, straight, and non-wired coat in the Pomeranian. Additionally, breeds show variation in patterns of growth - that is to say, parts of the dog's body where the coat may be longer or shorter. The same gene that controls wiriness of hair also causes furnishings to be present (e.g. beard, moustache, eyebrows) - compare the bearded collie, furnishings present, to the border collie, which lacks furnishings. Some breeds show feathering: fringes of longer hair on the ears, belly, tail, and back of the legs (e.g., Saluki and any of the setters). Dogs also vary in the thickness of the undercoat. Some dogs have only a single (rather than a double) coat, or a very reduced undercoat (e.g. the Vizsla), which results in a thinner coat. Certain breeds, especially spitz-type breeds, tend to have a thicker undercoat, which helps retain heat in cold and wet weather. Furthermore, complete hairlessness on parts of the body is present in breeds such as the Chinese Crested or the Xoloitzcuintli. == Shedding ==

Shedding of hair can occur continuously, but in many breeds is strongly influenced by hormones. Seasonal shedders shed most in spring and fall, following an increase or decrease in day length, and least in summer and winter, in response to constant day length. Cold temperatures stimulate hair growth, so that the heaviest shedding is in spring on dogs living in cold climates. Artificial lighting can alter the seasonal shedding pattern of dogs who live indoors. Other hormonal influences include dietary factors, reproductive hormones in intact dogs, and various medical conditions and disorders. Shedding that is done in a short period of time is known as "blowing the coat" or "blowing coat". Among the other coat types, dogs with fine silky coats (e.g., spaniels) are generally moderate shedders, those with an intermediate coat texture (e.g., mountain dogs) are generally heavy shedders, and those with thick stand-offish coats (e.g., spitzes) are generally very heavy shedders. is an example of a breed with single, low-shedding coat. "Non-shedding" dogs have greatly-reduced shedding due to alterations to the hair follicle growth cycle: • homozygosity for the furnishings (wire) allele - Most breeds with facial furnishings (including ones whose faces are usually shaved removing the furnishings) are low-shedding, but they must be homozygous, so dogs of mixed wire/non-wire parentage (e.g., terrier crosses or breeds with wire and non-wire varieties) can be heavy shedders. There are a few furnished breeds that shed more (e.g., Old English Sheepdog, Bearded Collie, Briard, Otterhound); • at least one copy of the single-coat (non-shedding) allele - Most dogs with a smooth coat are low shedding, as well as the fringed or flat coat. There are breeds with a very short coat that shed more (e.g., Basset Hound, English Bulldog, Pug, Toy Fox Terrier, Dalmatian, Vizsla, German Shorthaired Pointer); • single coat (no undercoat) plus furnishings (homozygous) - These breeds shed the least (e.g., Poodle, Soft-coated Wheaten Terrier). Hypoallergenic coat "[D]ogs are a relevant source of allergens, but diagnosing dog-related allergies may present difficulties ..." Some dog breeds have been promoted as hypoallergenic (which means less allergic, not free of allergens) because they shed very little. However, no canine is known to be completely nonallergenic. Often the problem is with the dog's saliva or dander, not the fur. Although breeds such as poodles, Bedlington terriers, bichons, yorkies, and wire-haired terriers are commonly represented as being hypoallergenic due to reduced shedding, the reaction that an individual person has to an individual dog may vary greatly. In a report, describing dog allergen extracts of dog hair, belonging to patients' dogs or from dogs of the same breed, with low molecular mass that are absent in extracts of commercial allergen test kits, it has been found that "[f]actors related to individual dogs seem to influence the allergenicity more than breed or gender." ==Show coats==

The nature and quality of a purebred dog's coat is important to the dog fancy in the judging of the dog at conformation shows. The exact requirements are detailed in each breed's breed standard and do not generalise in any way, and the terminology may be very different even when referring to similar features. See individual breed articles for specific information. == Nutritional impacts on coat ==

A dog's coat is an outward indicator of internal well-being. For this reason, coat health is an important aspect of pet care to many dog owners. Below is a table that summarizes the effects of several nutrients (minerals, vitamins) on the domestic canine coat, based on current evidence: === Trace minerals === Zinc Zinc contributes to hair growth and can prevent hair from becoming dry and brittle. Dogs can obtain zinc in their diet, through the addition of various ingredients, including; red meats, whole grains, poultry by-product meals, and fish meals. Copper Copper is a trace mineral that is required in the diet of canines at 7.3 mg/kg. Copper is involved in multiple enzymatic pathways. In dogs, a lack of copper in the diet, leading to a copper deficiency, results in incomplete keratinization. Lack of selenium in the diet of a dog can contribute to the occurrence of sparse coat growth. Dogs can obtain selenium in their diet through the addition of various ingredients including; tuna fish, halibut, sardines, beef, chicken, and egg. Vitamins Vitamin A Vitamin A deficiency can lead to rough coat, scaling of skin, and other dermatitis issues like alopecia. Vitamin B7 (Biotin) Vitamin B7, also known as biotin, is a water-soluble nutrient that is known to play a role associated with the maintenance and development of hair starting from the follicle. Although it has not been clinically shown to improve hair growth with supplementation alone, it has been shown to reverse deficiency in dogs born deficient. Symptoms of biotin deficiency include alopecia and achromotrichia. A clinical study of biotin showed the importance of biotin in coat pigmentation. There different stages of hair development, as shown in clinical studies using mice. The proper combination of these omega fatty acids is crucial to achieve optimal benefits. Proper omega 6:3 ratios have been shown to diminish allergy triggered immune responses, thus improving overall coat condition. The National Research Council (NRC) recommends a 2.6:1 to 26:1 omega 6:3 ratio for adult dog maintenance diets. The proper ratio of these fatty acids is crucial because each has an opposing role in inflammation within the body and both compete for the same enzymatic pathway. The specific role of vitamins A and E for coat health are explored elsewhere in this article, as they pertain to immune function. DHA acts even earlier in omega 6 metabolism, by inhibiting delta-6-desaturase. The anti-inflammatory properties of omega 3s stem from their ability to inhibit the inflammatory action of omega 6 fatty acids. A functional minimum has not been set forth by AAFCO, as one has yet to be determined. A reduction in inflammation of somatic tissues, skin especially, supports coat health. Omega 6 (linoleic acid) Omega 6 fatty acid, also known as linoleic acid, is found in poultry fat and the oil from safflower, sunflower, corn and flaxseed. Arachidonic acid is a well known metabolic derivative of linoleic acid, found only in animal sources. As mentioned above, arachidonic acid is a pro-inflammatory compound. It is critical to note once again that canines are unable to interconvert between omega fatty acids and over supplying linoleic acid promotes excessive inflammation in the body, which can potentially reverse the coat benefits seen by supplying omega fatty acids in the diet. In contrast, linoleic acid is also required for epidermal lipid function and water retention, which benefits coat shine. Having linoleic acid present in the diet has demonstrated a positive effect on skin, and thus by extension, coat. == See also ==