Tag Archives: Tibetan Terrier

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 […]

Genetics and the Dog: Breed Action

In some breeds, admitting to the occurrence of an inherited defect is hazardous. Many breeders will openly condemn those who confess to having had a problem. It is as if breeders believe that silence will make the defect go away. This is clearly not the case, indeed, it is more likely that defects will spread. It is far more mature to admit to problems and collectively try to solve them. In the short term there may be heartache and economic loss for some, but in the long term the breed will benefit. It is crucial that breeders do not simply rely on pedigree data vvhen trying to evaluate problems. If a defect is recessive or suspected as being recessive, then the need is not only for five generation pedigrees of affected animals but also numbers of the litter born, their sexes status and, in the case of defects seen in later life, the age at examination. Given such data, a geneticist can help a breed examine the problem in depth. Given a list of “affected” pedigrees only on is in danger of “tracing the defect to a certain dog” without being aware that all pedigrees, affected and normal, trace to him. Any widely used stud might appear in “affected” pedigree without actually being the source of the problem though in some Read more […]

Genetics and the Dog: Genes and defects

Dogs, like wolves from which they probably descend, have thirty nine pairs of Chromosomes. These are long thread-like structures found in each body cell and along the length of which are the genes. The number of chromosomes is fully documented but the number of genes quite unknown and likely to remain so in the foreseeable future. There are, however, likely to be many thousands and each one will influence a specific aspect of the dog or, in some instances, more then one aspect. A gene is found at a particular location on a particular chromosome and, as such it will influence a particular trait, Because a dog has two of each chromosome, one from the father and one from the mother, it has two of each gene. If the tvvo are identical, the genes are said to be homozygous and if they differ, they are said to be heterozygous for that trait. Two versions of a particular gene are called alleles. Thus we have the gene causing black pigment which comes in two versions One, designated B, causes black pigment to form in the dog while the alternative, b, prevents black pigment forming and instead leads to liver or chocolate pigment. The upper-case letter indicates a dominant allele vvhile the lower-case letter indicates a recessive. Read more […]

The faults and defects of the breeds: Non-Sporting Dogs

American Eskimo Dogs Hip dysplasia Bichons Frises Patella luxation Boston Terriers Neoplasias; Patella luxation, either medial or lateral; Swimmers syndrome, the inability to stand at four to six weeks; Vertebral abnormalities Bulldogs Spina bifida, caused by ununited neural arches; Neoplausa; Swimmers syndrome, the inability to stand at four to six weeks; Hip dysplasia; Elbow dysplasia; Flaccid shoulder joints; Thyroid disorders; Vertebral abnormalites Chinese Shar-Peis Patella luxation; Hip dysplasia; Elbow dysplasia; Swollen hock syndrome Chow Chows Hip dysplasia; Elbow dysplasia Dalmatians Muscular dystrophy Finnish Spitz Patella luxation French Bulldogs Hemivertebrae, which is the asymmetric abnormal development of vertebrae, resulting in scoliosis and crowding of one half of the body, producing a wedge-shape. It often results in neonatal death or spinal cord compression in older puppies. Keeshonds Thyroid and other endocrine disorders, primary hyperparathyroidism in older dogs; Patella luxation; Hip dysplasia; Neoplasias Lhasa Apsos Patella luxation, either medial or lateral; Hip dysplasia Poodles (Miniature) Dwarfism; Hypoplasia of dens; Atypical pannus; Patella luxation; Shoulder luxation; Read more […]