Tag Archives: Old English Sheepdog

The Globe And Orbit

Congenital Abnormalities Microphthalmos. Failure of the eye to develop to normal size is referred to as microphthalmos. Complete absence of the eye (anophthalmos) is extremely unusual in puppies and kittens. Microphthalmos is characterized by varying degrees of enophthalmos, with or without other ocular defects. Microphthalmos with multiple colobomas is an autosomal recessive trait linked to coat color in the Australian shepherd. In addition to small globes, affected dogs may have persistent pupillary membranes, cataract, equatorial staphylomas, choroidal hypoplasia, retinal dysplasia and detachment, and optic nerve hypoplasia. Vision is frequently impaired. Other breeds in which multiple ocular defects have been associated with coat color include the Great Dane, collie, Shetland sheepdog, and dachshund. Microphthalmos is also associated with inherited congenital cataracts in the miniature schnauzer, Old English sheepdog, Akita, and King Charles Cavalier spaniel. Microphthalmos occurs with retinal dysplasia in BedlingtonĀ terriers, Sealyham terriers, beagles, Labrador retrievers, and Doberman pinschers. Administration of griseofulvin to pregnant cats may produce microphthalmos in their offspring. Atypical Eye Position. Read more […]

The Lens and Vitreous

The lens develops rapidly in the early stages of embryogenesis, during which time it is nourished by the hyaloid vessel. The fully developed lens is avascular; by the second week of life, no remnants of the hyaloid system should remain. The normal lens often exhibits minor imperfections that can be easily detected with magnification in dogs and cats younger than 1 year. These include prominent anterior and posterior Y sutures and minute granules in its nucleus and cortex. A mosaic of brown pigment spots is occasionally seen on the anterior lens capsule near the center of the pupil, representing remnants of embryonic mesoderm. Disease of the vitreous would be expected to influence the lens or retina because of its attachments at the posterior lens surface and the optic disc. Congenital Abnormalities Congenital lens abnormalities include alterations in size or shape. Congenital absence of the lens (aphakia) is uncommon. In microphakia, the margin of the abnormally small lens along with elongated ciliary processes may be observed after pupillary dilation. Microphakia occurs along with other ocular defects in the Saint Bernard and beagle and in cats. Luxation of the microphakic lens may cause glaucoma. Lenticonus is a Read more […]

The Retina and Optic Nerve

Tapetal coloration of the fundus of the puppy and kitten is usually gray or blue at 6 to 8 weeks of age, gradually acquiring its adult coloration by 4 to 7 months of age when the tapetum matures. Myelination of the optic disc may also be incomplete in the puppy and kitten, giving the impression of a small, well-defined nerve head that takes on a more fluffy appearance as adult myelination occurs.Both congenital and acquired disorders of the retina and optic nerve are recognized in the young dog and cat. These may be inherited, as with collie eye anomaly, or secondary to postnatal influences, as occurs with canine distemper-induced retinitis. Congenital abnormalities can be diagnosed as early as 6 weeks of age, when the posterior segment is clearly observed. The more common congenital abnormalities of the canine fundus are summarized in Table Congenital Abnormalities of the Canine Fundus. Acquired abnormalities develop with advancing age and in this discussion are limited to those in dogs and cats younger than 6 months of age. Table Congenital Abnormalities of the Canine Fundus (diagnosed as early as 6-8 wk of age). DISORDER BREED CHARACTERISTIC FEATURES Collie eye anomaly Collie, Shetland sheepdog, Read more […]

The Trachea and Major Bronchi

Cough is the most common clinical sign associated with tracheal and bronchial disease. Following a history and thorough physical examination to rule out infectious tracheobronchitis, thoracic and soft-tissue cervical radiographs may be indicated. Thoracic radiography is perhaps the single most important diagnostic test in the evaluation of the puppy or kitten that presents with cough as its primary complaint. Tracheal hypoplasia, extraluminal compressive diseases, diseases causing tracheal stenosis, intraluminal masses, and tracheal collapse may be apparent radiographically. Tracheoscopy with a small-diameter endoscope (approximately 3.5 to 5 mm in diameter or a rigid arthroscope) is useful in evaluating the trachea when obstructive or mucosal disease is suspected. It is especially useful in the diagnosis of tracheal collapse, tracheal foreign body, tracheal stenosis, parasitic tracheobronchitis, and tracheal osteochondroma. Congenital Disorders PRIMARY CILIARY DYSKINESIA Primary ciliary dyskinesia is a congenital respiratory disorder that is characterized by absent or deficient mucociliary clearance (). The ciliary dysfunction reduces mucociliary transport, which frequently leads to persistent or recurrent rhinitis, Read more […]

Intention tremors due to cerebellar disorders

Tremors that occur when an animal intends to move in a goal-orientated activity are most often the result of cerebellar disease (). Degenerative diseases Cerebellar cortical degeneration Cerebellar cortical degeneration, also termed cerebellar abiotrophy, is usually an inherited disease in dogs () with few reports in cats. Primary cerebellar cortical degeneration refers to degeneration and loss of Purkinje cells, molecular cells and granule cells. Clinical signs: These diseases are recognized syndromes in American Staffordshire Terriers, American Pit Bull Terriers, Kerry Blue Terriers, Gordon Setters, Rough-coated Collies, Border Collies, Brittany Spaniels, Bullmastiffs, Old English Sheepdogs and occur rarely in Samoyeds, Airedales, Finnish Harriers, Labrador Retrievers, Golden Retrievers, Beagles, Cocker Spaniels, Cairn Terriers, Great Danes, Scottish Terriers and others (). Clinical signs usually begin between 3 and 12 months of age. However, a subset of adult onset diseases occur with signs starting from 2-8 years of age in the Brittany Spaniel (), Gordon Setter (), Old English Sheepdog (), American Staffordshire Terrier () and Scottish Terrier (). Other signs of cerebellar disease that accompany cerebellar Read more […]

Anticancer chemotherapy of the nervous system: Alkylating agents

The major alkylating agents are the nitrogen mustards and the nitrosoureas. These drugs covalently alkylate various cellular constituents. Most importantly for cancer treatment, alkylation occurs between the bases of DNA molecules of rapidly dividing cancer cells. This reaction cross-links the bases of DNA, causing cessation of DNA synthesis and cell death. The most significant effect is to bind and cross-link double-stranded DNA; therefore, these drugs are referred to as bifunctional alkylating agents. Bifunctional alkylating agents are more cytotoxic and produce fewer drug-induced tumours than monofunctional agents. Alkylation of the DNA molecule causes abnormal base pairing, misreading of the genetic code and excision of bases, which prevents DNA transcription and RNA synthesis. These drugs are more active on growing cells in the cell cycle than on dormant ceils. However, they can act at any point of the cell cycle and therefore are non-cycle-specific. They are most active when DNA is dividing, such as in the G1 Phase and S Phase. As a consequence, in addition to their effect on cancer cells, they will also affect rapidly growing normal cells such as bone marrow cells and gastrointestinal mucosa. Nitrogen mustards The Read more […]

Idiopathic dilated cardiomyopathy

Dilated cardiomyopathy (DCM), next to valvular endocardiosis, is the most commonly diagnosed cardiac disorder in dogs. In most cases the cause is not apparent; the most popular concept is that the aetiology for dilated cardiomyopathy in dogs is multifactorial. Cases of dilated cardiomyopathy in association with a deficiency of myocardial L-carnitine have been reported in one family of boxers suggesting that nutritional factors may be involved in the pathogenesis. L-Carnitine is necessary for the transport of long chain fatty acids into the mitochondria of cardiac muscle cells and a deficiency results in impaired mitochondrial energy production. More recently, it has been shown that some dogs with dilated cardiomyopathy have reduced plasma taurine levels. In humans, cardiomyopathy is associated with depression of the cellular Na+, K+-ATPase pump and a reduction (down regulation) of myocardial beta-adrenergic receptors. Whether a similar situation exists in dogs with dilated cardiomyopathy is not clear. A recent study reported no significant difference in the beta receptor density in four dogs with dilated cardiomyopathy compared to normal dogs. Immune-mediated disease with the production of antibodies against altered Read more […]

Bone Heart Diseases

Diseases Of Different Organs Cardiac Failure Heart problems usually relate to either valve disease or deterioration in the heart muscle. Both make the heart less efficient in maintaining circulation, with consequent congestion due to accumulation of abdominal fluid in severe cases. Some dogs develop a characteristic dry cough on exercise. Hot summer days mean added stress on dogs with faulty heart function, and fainting and collapse can easily occur if the dog stays in the sun, especially if the dog is also obese. Some infectious diseases result in deterioration of the heart muscle, but heart valve deterioration is usually associated with age, although the two diseases may occur simultaneously. Drugs are available for many heart conditions and suspected cases need veterinary attention sooner rather than later. With proper treatment and revised life style they need not be fatal. Parasitism caused by heart worm (Dirofilaria immitis) can bring serious heart disorders. The parasite is widespread in the United States and in tropical areas of Asia and Africa. A mosquito is needed to complete the life-cycle of heart worms. Treatment and prevention are specialized areas of medicine, sometimes requiring surgical intervention. Endocarditis When Read more […]

Sensory Abilities: Audition

The dog’s ear is composed of an outer ear (pinna), auditory canal, and various structures designed to convert sound waves into auditory information. The pinna gathers and directs sound into the auditory canal, where it is carried to the tympanic membrane or eardrum. The eardrum is an extremely sensitive and elastic membrane reacting to the slightest vibrations on its surface: movement of less than one-tenth the diameter of a hydrogen atom can produce an audible sensation. The vibrations caused by the pressure of sound waves on the eardrum are mechanically conducted to the cochlea through the mediation of three tiny bones or ossicles: the malleus, the incus, and the stapes. The cochlea is a snail-like tubular structure that is innervated by the auditory nerve. Sound vibrations are passed into the cochlea at the oval window. These vibrations cause a fluid wave in the cochlear fluid, which causes a rippling effect against the surrounding basilar membrane. The vibratory displacement of the basilar membrane stimulates auditory receptors (called hair cells) to bend rhythmically, thereby evoking a nerve potential that is carried by individual fibers into the auditory nerve. Different sounds are distinguished by the specific Read more […]

The faults and defects of the breeds: Herding Dogs

Australian Cattle Dogs OCD (osteochondrities dissecans) of the hock Australian Shepherds Hip dysplasia; Dwarfism; Spina bifida Bearded Collies Hip dysplasia Belgian Malinois Hip dysplasia Belgian Sheepdogs Hip dysplasia; Neoplaisa Belgian Tervurens Hip dysplasia; Thyroid disorders Border Collies OCD (osteochondrities dissecans); Hip dysplasia Bouviers des Flandres Elbow dysplasia; Hip dysplasia Briards Thyroid disorders; Hip dysplasia Cardigan Welsh Corgis Medial patella luxation Collies (Rough and Smooth) Dwarfism; Neoplasias German Shepherd Dogs Dwarfism; Panosteitis, shown as limb pain and intermittent lameness between the ages of 6 and 12 monts; Hip dysplasia; UAP (ununited anconeal process); Cartilagenous Exostosis; Pannus; Elbow dysplasia; Neoplasias; Thyroid disorders; OCD (osteochondrities dissecans); Degenerative myelopathy causes progressive hind limb paralysis in middle age to older dogs. Old English Sheepdogs Hip dysplasia; Wobblers syndrome Pembroke Welsh Corgis IVD (intervertebrate disk disease); Hip dysplasia; Swimmers syndrome Pulik Hip dysplasia Shetland Sheepdogs Hip dysplasia; Dwarfism; Thyroid disorders; Neoplasias; Muscular dystrophy Read more […]