Tag Archives: Shetland Sheepdog

Dental Disease and Care

An oral examination should be performed each time a puppy or kitten is presented. Many pathologic or potentially pathologic conditions can be detected at an early age and corrective measures taken. Introducing the pet owner to the concept of oral home care and regular professional dental prophylaxis are the two most important responsibilities of the veterinarian with regard to dental disease care and prevention. Tooth Morphology There are three types of teeth in the deciduous dentition of puppies and kittens: incisor (I), canine (C), and premolar (P); a fourth type, molar (M), is found in the permanent dentition. Each type is designed to be self-cleaning in the non-crowded scissors occlusion, when the animal eats a natural diet, that is, catches its prey. Each tooth type serves a specific function. Incisor teeth are for grooming and nibbling, canine teeth are for grasping and tearing, premolars are for shearing, and molars are for grinding. The cat, a true carnivore, has no occlusal surface on the mandibular molar. The maxillary molar is small and vestigial in the cat (). Each tooth is covered with enamel, the hardest body substance. The bulk of the tooth is dentin, a living tissue that continues to be deposited Read more […]

Autoimmune Disorders

Pemphigus complex the pemphigus complex comprises a group of rare autoimmune diseases described in dogs and cats the diseases are vesiculobullous ulcerative disorders of the skin and often the mucous membranes autoantibody is directed against the epidermal intercellular cement substance and may be demonstrated by direct immunofluorescence testing histologically the pemphigus complex is characterized by acan-tholysis (loss of cohesion between individual epidermal cells) Pemphigus foliaceus the most common of the autoimmune diseases dogs and cats no age, breed or sex predisposition Clinical features often begins on the face, nose and ears as a vesiculobullous or exfoliative pustular dermatitis () footpads are frequently involved with hyperkeratosis mucocutaneous lesions are uncommon Diagnosis history physical examination histological examination: subcorneal acantholysis leading to the development of a cleft. Within the cleft there are neutrophils and eosinophils direct immunofluorescence may reveal intercellular deposition of immunoglobulin throughout the epidermis Differential diagnosis bacterial folliculitis dermatophyte infection seborrhoea systemic lupus erythematosus discoid Read more […]

Congenital and Hereditary Disorders of the Kidney

Structural Anomalies of the Kidney RENAL AGENESIS Renal agenesis is the complete absence of one or both kidneys. Bilateral renal agenesis is fatal and is a cause of early death in puppies and kittens (). Unilateral renal agenesis is more frequendy observed in puppies and kittens than is bilateral agenesis (). Unilateral renal agenesis may affect either kidney and is usually accompanied by ipsilateral ureteral agenesis. The etiopathogenesis of renal agenesis in dogs and cats is uncertain. A familial predisposition for renal agenesis in beagles, Shetland sheepdogs, and Doberman pinschers supports a genetic basis for the anomaly (Table 17-1). Unilateral renal agenesis may remain clinically silent, provided the contralateral kidney undergoes sufficient compensatory change to maintain normal hemostasis. Clinical findings may include an inability to palpate both kidneys or to detect a kidney by ultrasonography or contrast urography. Because of close associations in the development of the urogenital system, findings of abnormal or absent vas deferens, epididymal tails, or uterine horns at the time of castration or ovariohysterectomy should arouse suspicion of concurrent unilateral renal agenesis. Because unilateral renal Read more […]

Congenital Deafness

Deafness that is present at or soon after birth may have either an acquired or a hereditary etiology and may occasionally occur in any puppy whether pure bred or mixed breed. Acquired deafness may be caused by viral infections, anoxia, or the ototoxic side effects of drugs or other materials. Because dogs and cats are born deaf, deafness in a puppy or kitten is not abnormal up to a certain age. In cats the earliest discriminating hearing tests were performed at the age of 7 days. Cochlear potential measurements from a round-window electrode were found to be conclusive about the presence or absence of hearing in cats over 7 days of age (). In dogs, hearing tests were performed from the age of 4 weeks () by means of cochlear potential measurements from round-window electrodes () or brainstem auditory evoked responses (BAERs) (). Testing the Hearing of Young Puppies In our laboratory, two Irish wolfhound puppies and two beagle puppies were investigated for hearing from the third day after birth. Brain-stem auditory evoked potentials (BAERs) were recorded from surface electrodes (Dantec) on the pinnae and the skin over the parietal bone on the midline. For the recording of air-conducted BAERs, each pup was placed in a Read more […]

The Eyelids

Developmental Abnormalities Eyelid Agenesis. Eyelid agenesis is a congenital defect of the eyelid margin resulting in absence of varying segments of the eyelid margin, palpebral conjunctiva, and fornices. The agenesis may be unilateral or bilateral, affecting the kitten more often than the puppy. The lateral one third or two thirds of the upper eyelid margin is most frequently involved. Keratitis and ulceration result from direct contact of the cornea with facial hairs and from exposure secondary to imperfect eyelid closure. Small eyelid defects may be successfully managed with ophthalmic lubricant ointments applied three to four times a day to reduce ocular irritation or by performing an entropion procedure to evert the offending hairs. If one third of the eyelid or more is missing, a pedicle graft from the inferior temporal aspect of the lower eyelid can be transposed to the upper eyelid. Distichiasis. Distichiasis is an extra row of eyelashes (cilia) that protrudes from the orifices of the meibomian glands onto the eyelid margin. The upper, lower, or both eyelids may be involved (). Congenital distichiasis often occurs in the English bulldog, toy poodle, miniature poodle, American cocker spaniel, golden retriever, Read more […]

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 Bedlington 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 Cornea

Congenital Abnormalities Comeal Opacities. The cornea of the newborn puppy or kitten is a light blue color; or at least the cornea is less clear than that of the adult. In 2 to 4 weeks, corneal clearing is sufficient to permit ophthalmoscopic examination. It is not unusual to observe multifocal or diffuse faint white opacities in the corneas of young puppies and kittens. The opacities represent superficial foci of edema, and most are self-limiting. The cause of these opacities is unknown. Therapy is not necessary unless the opacities are accompanied by a mucopurulent discharge, in which case topical ophthalmic antimicrobial preparations may be applied. Animals born with their eyelids open often have diffuse corneal edema that clears in 14 to 18 days. Because reflex lacrimation is absent at birth, the exposed cornea is subject to desiccation and infection and can be avoided by frequent application of a broad-spectrum antimicrobial ointment every 3 or 4 hours until the animal is 10 to 12 days old. Cats with lysosomal storage diseases may develop corneal opacities related to the accumulation of polysaccharides within the endothelial cells and fibroblasts of the cornea. Fine granular deposits in the corneal stroma may Read more […]

The Anterior Uvea

The irides of the puppy and kitten are often a different color than those of the adult. The blue-gray iris of puppies and kittens usually changes to the adult coloration within a few weeks. Iris color is ultimately related to the degree of stromal pigmentation and is influenced by coat color. Congenital Abnormalities Persistent Pupillary Membranes. Persistent pupillary membranes are strands of tissue that arise from the anterior iris surface and represent remnants of an embryonic vascular system. The persistent pupillary membranes may be confined to the iris surface or may extend from the iris to the cornea or lens (). Persistent pupillary membranes are inherited in the basenji. Iris Cysts. Iris cysts are floating, fluid-filled vesicles that arise from the posterior iris epithelium and are usually found in the anterior chamber. Iris cysts may be unilateral or bilateral and singular or multiple in number. Pupillary Abnormalities. A notch-like defect (coloboma) is occasionally seen in the ventronasal pupillary border of young dogs and cats, resulting in a keyhole-shaped pupil. An eccentric pupil (corectopia) may accompany multiple ocular defects, as occurs in the Australian shepherd. Eccentric pupils are usually 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 […]

Adverse CNS reactions caused by drugs

Ivermectin and related drugs The adverse central nervous system effects caused by ivermectin, and similarly acting drugs such as moxidectin and milbemycin, are well documented in the veterinary literature. Theavermectin and milbemycin classes of parasiticides enhance the effects of GABA and stimulate its release from nerve endings. In parasites, increased GABA activity causes paralysis and death of the organism. Ordinarily dogs and cats are resistant to these effects because these drugs do not cross the BBB. However, when these drugs are administered to certain breeds of dog that permit them to cross the BBB, central nervous system toxicity results. Collies, Shetland Sheepdogs, English Sheepdogs, Australian Shepherd Dogs and perhaps other breeds have this susceptibility. It is now recognized that dogs susceptible to ivermectin toxicosis have a mutation in the MDR1 gene that codes for P-gp in the blood-brain barrier. The adverse central nervous system effects of ivermectin are most likely caused by accumulation of the drug in the brain because P-gp, which normally would transport the drug out of the brain through the BBB, is deficient or inhibited. In mice deficient in expression of P-gp (CF-1 mice) the doses of ivermectin Read more […]