Friday, 7 March 2008



The location of the withers on a horse.
The location of the withers on a horse.

The withers is the highest point on the back of a non-upright animal, on the ridge between its shoulder blades.


They are made up by the dorsal spinal processes of the first 5 to 9 thoracic vertebrae (every horse has 18 thoracic vertebrae), which are unusually long in this area. The processes of the withers are less than 6" in height on the average horse. Since they do not move relative to the ground (as does the horse's head), the height of a horse is measured from the ground to the withers. Horse sizes are extremely variable, from small pony breeds to large draft breeds. The height of the withers on an average Thoroughbred is 16 hands (5' 4").

Conformational issues

The withers of the horse are considered in evaluating conformation. Generally, a horse should have well-defined withers, as they are considered an important attachment point for the muscles of the torso. Withers of medium height are preferred, as high withers make it difficult to fit a saddle and are often associated with a narrow chest, and low withers (known as "mutton withers") do not provide a ridge to help keep the saddle in place.

More importantly, the dorsal spinal processes provide an attachment for the muscles that support the shoulder. Horses do not have a clavicle, so the shoulder can freely rotate backwards. If the vertebrae of the withers are long (front to back), the shoulder is more free to move backwards. This allows for an increase of stride length (and so it can increase the horse's speed). It is also important in jumping, as the shoulder must rotate back for the horse to make his forearm more parallel to the ground, which will then raise the animal's knees upward and get the lower legs out of the way. Therefore, the withers have a direct impact on one of the most important points of conformation: the shoulder.


In dogs, the height of the withers is often used to determine the dog's jump height in various dog sports. It is also often a determining factor in whether the dog conforms to the show-quality standards for its breed.

Medical problems

Inflammation of the bursa in this region is called fistulous withers by veterinary surgeons



A horse's snout.
A horse's snout.

A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. The snout is also often called a muzzle. A piece of equipment also called a muzzle can be placed over the snout to prevent the animal from biting or eating, often used before and after horse races (see animal muzzle).

A wet snout nose is called a rhinarium.

Dog's muzzle

Dogs' muzzles range in shape from extremely long and thin (dolichocephalic), as in the Rough Collie to nearly nonexistent because it is so flat (extreme brachycephalic), as in the Pug. Some breeds, such as many sled dogs and Spitz types, have muzzles that somewhat resemble the original wolf's in size and shape, and others in the less extreme range have shortened it somewhat (mesocephalic) as in many hounds.

This Black and Tan Coonhound's flews hang well below its lower jaw.
This Black and Tan Coonhound's flews hang well below its lower jaw.

The muzzle begins at the stop, just below the eyes, and contains the dog's nose and mouth. Most of the dog's upper muzzle contains organs for detecting scents. The loose flaps of skin on the sides of the upper muzzle that hang to different lengths over the dog's mouth are called flews. The snout is considered a weak point on most animals, because of its structure an animal can be easily stunned or even knocked out by applying sufficient force.

>>Stenotic nares

Stenotic nares

Before surgury
Before surgury
After surgury
After surgury

Stenotic nares is part of the brachycephalic syndrome of short-nosed dogs. Breeds such as Boxers, Bulldogs, Cavalier King Charles Spaniels, Pugs, Boston Terriers, Shih Tzus, Lasa Aphsas, etc. are all considered brachycephalic breeds. Stenotic nares means the nostrils are pinched or narrow. This makes it more difficult to breathe and causes snorting and snoring in these animals. It is a congenital trait; these animals are born with it. Veterinarians perform a simple surgery to help widen the nares, often at the same time as a spay or neuter.

Saturday, 12 January 2008

>>Self colour

Self colour

The Russian Blue is a cat breed selected for a self blue colour
The Russian Blue is a cat breed selected for a self blue colour
This golden Lhasa Apso has some slight colour variation in his coat, but each hair is a uniform shade and he has no white markings, making him a self coloured dog
This golden Lhasa Apso has some slight colour variation in his coat, but each hair is a uniform shade and he has no white markings, making him a self coloured dog

A self colour refers to the top coat colouration of several domestic animals, such as dogs, pet rodents and cats. It refers to hairs of a uniform shade, with no banding or tipping of another colour. A true self coloured animal should also have no white markings such as bibs or blazes.

In contrast, a sable (dogs), ticked (dogs or cats) or agouti (cats or rodents) coat has two or more different colours along the shaft of the hair, with one colour at the base and usually a darker colour, such as black, at the tip.



The pastern is a part of the horse between the fetlock joint and the hoof, or between the wrist and forepaw of a dog. It is the equivalent to the two largest bones found in the human finger. It was famously mis-defined by Dr Johnson in his dictionary as "the knee of a horse". On this being pointed out to him by a lady, he gave in reply the famous quotation: "Ignorance, madam, pure ignorance."

Anatomy and Importance of the Pastern

Shock absorption of the pastern.
Shock absorption of the pastern.

The pastern consists of two bones, the uppermost called the "large pastern bone" or proximal phalanx, which is located just under the fetlock, and the lower called the "small pastern bone" or middle phalanx, located between the large pastern bone and the coffin bone (also see Equine forelimb anatomy). The joint between these two bones is aptly called the "pastern joint." This joint has very limited movement, but does help to disperse the concussive forces of the horse's step and also has some influence on the flexion or extension of the entire leg.

The length of the pastern is determined by the length of the first phalanx. The short pastern bone is less a determinant because it is smaller, at 2 inches in length, and part of it is encased in the hoof.

The pastern is vital in shock absorption. When the horse's front leg is grounded, the elbow and knee are locked. Therefore, the fetlock and pastern are responsible for all the absorption of concussive forces of a footfall. Together, they effectively distribute it among both the bones of the leg and the tendons and ligaments.

Matching Angles

Broken hoof-pastern angle, due to long toe.


The slope of the shoulder is often the same as the slope of the pastern. However, differing angles in these two joints will not affect athletic performance.


The pastern angle should always match the angle of the hoof after it is trimmed (the angle will change as the hoof grows and may be off in a few weeks). This keeps the bones of the pastern, the coffin bone, and their joints in proper alignment, with a straight line running through their core. An angle broken forward or back increases the stress on these bones, joints, tendons, and ligaments. If the angle does not match, it is often an indication of poor farrier work.


The pastern is evaluated when a horse studied conformationally, as it will effect the gait of the horse and the soundness of the joints above it. Traditionally, the ideal pastern of the front leg has a 45 degree angle. However, this angle has been revised to a slightly steeper angle of 47-55 degrees, as the traditional angle, although it makes for comfortable riding, greatly increases the chance of breakdown.

Because there is less need for shock absorption in the hindleg, its pasterns should be shorter and more upright than those of the front leg, to increase its strength (about 49-59 degrees, and sometimes greater). If the hind pasterns are the same angle as the front, or too sloping in general, then they are likely to break down during the horse's career, especially if the horse in employed in strenuous work.

A nicely-sloped pastern increases the likelihood of a long career. It improves the animal's ability to travel on uneven terrain, helps him withstand the rigors of a competition or race, and makes the gait more comfortable for the rider.

The length of the pastern is also important. The best length for the pastern is 1/2 to 3/4 the length of the cannon bone.

Long, sloping pasterns

Note the length of the pastern in relation to the cannon bone.

Long, sloping pasterns are more than 3/4 the length of the cannon bone. They are sometimes bred for in a riding horse because they increase the shock-absorption ability of the leg, making the horse's gaits smoother and more comfortable for the rider. However, they have the distinct disadvantage of being weaker than more upright pasterns. This is because many of the tendons and ligaments that go down the back of the leg continue under the back of the fetlock joint, and attach to either the pastern bones or the coffin bone. When the horse puts weight on his leg, the fetlock sinks closer to the ground, which is a needed response as it helps to absorb the shock of the footfall. However, when the pasterns are too long or sloping it does not support the fetlock enough, and the fetlock may hyper-extend, possibly to the point where the ergot touches the ground. This stresses the soft tissues that run under the fetlock because they are stretched longer. If stretched too much, they may tear or rupture.

Medical problems that may result from long, upright pasterns include:

  • Bowed Tendon
  • Sesamoiditis
  • A fracture of the sesamoid bones found at the back of the fetlock, should the joint hyperextend to the point where it touches the ground. This is especially likely if the horse is tired, such as at the end of a race.
  • Injury to the suspensory ligament
  • Ringbone, due to excessive stress on the pastern joint

Long, sloping pasterns are commonly seen in Thoroughbreds, Saddlebreds

Short, upright pasterns

Draft horse with upright (65 degree) pasterns.
Draft horse with upright (65 degree) pasterns.

Short, upright pasterns are less than 1/2 the length of the cannon bone. They are beneficial in that they decrease the chance that the horse will suffer from soft-tissue injury. However, upright pasterns increase concussion by transmitting more of the shock of footfalls to the bones rather than the tendons. This not only makes the gaits uncomfortable due to the jarring, but also increases the chance of arthritis and may shorten the animal's career. A short, upright pastern also decreases the stride length of the gait, which again makes the gait more uncomfortable and decreases the efficiency of the horse's movement (since he must take more strides per meter than a longer-strided horse).

Medical problems that may be caused by short, upright pasterns are usually a result of excess concussion. They include:

Short, upright pasterns are often seen in draft horses. This is because draft horses bred for pulling rather than riding (and so they were not selected for smooth gaits of a saddle horse), and because upright pasterns give more leverage to dig into the ground as the horse pulls a heavy load.

Short, upright pasterns are also commonly seen in Quarter Horses, Warmbloods, and Paint Horses. However, riding horses are more likely to have problems with upright pasterns than draft horses because they tend to work at faster speeds.

Due to the lack of shock absorption, horses that have upright pasterns should be kept off hard surfaces whenever possible.

>>Natural bobtail

Natural bobtail

A natural bobtail is a tail which due to a mutated gene grows to a shortened length or is completely cut off at the base of the spine. The term also refers to animals carrying the gene for a naturally short tail or animals that naturally have no tail. The genes for the shortened tail may be dominant or recessive depending on the species.

Due to anti-tail docking legislation, natural bobtails are growing in importance in the hobby of dog fancy for some traditionally docked breeds. For example, one Boxer breeder and geneticist in England has successfully petitioned the Kennel Club for permission to cross Corgis into his lines and then backcross to Boxers, introducing the gene into his lines. This would have been unheard of in decades past. A number of these bobtail Boxers have been successfully exported to various countries around the world.

In Australia, the price for a registered purebred Miniature Fox Terrier bitch carrying the gene has more than tripled.

Animals with a natural bobtail

Domesticated breeds with a natural bobtail

Breeds in which bobtails are known to occur

Wild species with natural bobtails

Sunday, 6 January 2008

>>Merle (coat colour in dogs)

Merle (coat colour in dogs)

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Blue merle Border Collie puppy
Blue merle Border Collie puppy

Merle (In Welsh:Brych) is a colour combination in dogscoats. It is a solid base color (usually red/brown or black) with lighter blue/gray or reddish patches, which gives a mottled or uneven speckled effect. Although most breeds that can have merle coats also typically have white markings (such as around the neck, under the belly, and so on), and often tan points (typically between the white and the darker parts of the coat), these are separate colors from the merle; some dogs do appear completely merled with no white or tan markings.

Merle can also alter other colors and patterns besides the usual red or black. These combinations such as Brindle Merle or Liver Merle are not typically accepted in breed standards.

In addition to altering base coat color, merle also modifies eye color and coloring on the nose and paw pads. The merle gene modifies the dark pigment in the eyes, occasionally changing dark eyes to blue, or part of the eye to be colored blue. Since merle causes random modifications, however, both dark-eyed, blue-eyed, and odd-colored eyes. Color on paw pads and nose may be mottled pink and black.

Merle is a distinguishing marking of several breeds, particularly the Australian Shepherd, and appears in others, including the German Coolies in Australia, the Shetland Sheepdog, various Collies, the Welsh Corgi (Cardigan), the Pyrenean Shepherd, the Bergamasco Sheepdog, the Catahoula Leopard Dog, the Koolie, and the Old English Sheepdog. In Dachshunds the merle marking is known as "dapple". Merle is also less commonly found in the Chihuahua, the Pomeranian, the Pit Bull, and the Cocker Spaniel; it is not, however, a recognized color in these breeds. The merle gene also plays a part in producing harlequin Great Danes.

Merle is actually a heterozygote of an incomplete dominance gene. If two such dogs are mated, on the average one quarter of the puppies will be double merles ("double dilute") and some percentage of these double merle puppies could have eye defects and/or could be deaf. Knowledgeable breeders who want to produce merle puppies mate a merle with a non-merle dog; roughly half the puppies will be merles without the risk of vision or hearing defects.

In January 2006, scientists at Texas A&M University announced the discovery of a mobile genetic unit called a retrotransposon, responsible for the merle mutation in dogs.

A phantom merle is one with such small patches of merle--or none at all--that it appears to be a nonmerle.In America, a dog with the phantom merle coloring is described as being "cryptic for merle."

>>Hip score

Hip score

Hip scoring is a procedure used to determine the degree of hip dysplasia in dogs and other animals and reporting the findings in a standard way.

The hip score is the sum of the points awarded for each of nine radiographic tures of both hip joints.

The British Veterinary Association uses the following criteria to determine hip score:

  1. Norberg Angle
  2. Subluxation
  3. Cranial Acetabular Edge
  4. Dorsal Acetabular Edge
  5. Cranial Effective Acetabular Rim
  6. Acetabular Fossa
  7. Caudal Acetabular Edge
  8. Femoral Head/Neck Exostosis
  9. Femoral Head Recontouring

The lower the score, the less the degree of dysplasia present. The minimum (best) score for each hip is zero and the maximum (worst) is 53, giving a range for the total of 0 to 106.

The following table compares the scores recognised by Orthopaedic Foundation for Animals (OFI), Fédération Cynologique Internationale (FCI), the British Veterinary Association (BVA) and Verein für Deutsche Schäferhunde (SV).

OFA (USA) FCI (European) BVA (UK/Australia) SV (Germany)
E A-1 0-4 (no > 3/hip) Normal
G A-2 5-10 (no > 6/hip) Normal
F B-1 11-18 Normal
B B-2 19-25 Fast Normal
M C 26-35 Noch Zugelassen
Mod D 36-50 Mittlere
S E 51-106 Schwere

The average hip scores in the year 2005 for popular breeds from Australia are tabulated below:

Breed Average score
Airedale Terrier 13
Alaskan Malamute 11
Belgian Shepherd 9
Bernese Mountain Dog 11
Border Collie 9
Bull Mastiff 23
Cavalier King Charles Spaniel 15
Curly Coated Retriever 11
Doberman 9
German Shepherd Dog 13
Golden Retriever 16
Irish Setter 15
Japanese Akita 11
Labrador Retriever 12
Mastiff 11
Newfoundland 21
Old English Sheep Dog 17
Rhodesian Ridgeback 7
Rottweiler 10
Samoyed 19
Siberian Husky 6
St. Bernard 18
Staffordshire Bull Terrier 12
Weimaraner 10