Animalia Life

The Breed History
The breed was developed in the US by crossing a number of toy breed dogs. Foundation breeds include Manchester terrier, Miniature Pinschers, Chihuahua, and obviously, a fox terrier (Smooth Fox). Beginning in the 1930's, breeders carefully crossed to a number of toy breeds to calm the personality a bit, but keep the touch of spunk, and the look of the Smooth fox. The AKC fully recognized the Toy Fox Terrier breed in 2003, as its 148th breed, in the Toy division.

Breeding for Function
The goal of breed development was to produce a small fox terrier, with temperament well suited for a close companion, house dog. The terrier base of the breed makes them well suited to trials of agility and they are well suited to obedience, and even retain their love of hunting and will flush targets out of holes. Animated movement, fit and agile, strong and excellent endurance characterize these spunky little dogs.

Physical Characteristics
Height at Withers: Ideal 9-11" (23-28 cm), 8.5-11.5 in. (21.5-29 cm) accepted.
Weight: 3.5-7 lbs. (1.5-3 kg.)
Coat: A short, shiny coat which may be a bit longer at the ruff. Soft hair texture. Patterns vary, but body is mostly white and head is mostly solid. Tricolor black, tan and white with defined marking size and location described by the breed standard. Other tri-colors include chocolate/tan/white. Bi-colors include white and tan, white and chocolate, and white and black.
Longevity: 13-14 years
Points of Conformation: Square conformation, strong bone but not coarse. A soft wedge, the skull is moderate in size, stop is moderate, muzzle parallel to top of skull. Head is refined, with an alert expression, ears are prick and close/high set, with a v-shaped pinna. Ears can take up to 6 months to fully prick. Palpebral margins are black or self in chocolates, round prominent wide set eyes are dark in color. Nose also black or self in chocolates. Teeth scissors bite. High head carriage, the neck is tapered towards the head, and is not throaty. Well sloped shoulder and front of chest prominent. Level topline smoothly merges with tail, thorax is deep and ribs well sprung, abdomen has moderate tuck up. Limbs straight, the feet are compact and small, with oval shape and well knuckled up, dewclaws will usually be removed from rear limbs. Gait is long, low and smooth-topline remains straight. The tail is high set and usually docked to the 3-4th vertebra joint.

Recognized Behavior Issues and Traits
Reported characteristics include: Active, game and courageous, playful, high intelligence, a bit of toy - bit of terrier mixed in for personality and activity level, these little dogs stay playful late in life. Loving, with typical terrier devotion they are also adaptable, spirited and determined.

Normal Physiologic Variations
None Reported

Drug Sensitivities
None Reported

Inherited Diseases
Patella Luxation: Polygenically inherited laxity of patellar ligaments, causing luxation, lameness, and later degenerative joint disease. Treat surgically if causing clinical signs. Reported 12.8x odds ratio versus other breeds. OFA reports 4.2% affected. Reported as "commonly identified" in the TFT Health Survey.
Hip Dysplasia and Legg-Calve Perthes Disease: Polygenically inherited traits causing degenerative hip joint disease and arthritis. Too few Toy Fox Terriers have been screened by OFA to determine an accurate frequency.
Congenital Hypothyroidism with Goiter: An autosomal recessive disorder in Toy Fox Terriers. Neonatal affected pups exhibit inactivity, abnormal hair coat, stenotic ear canals, and delayed eye opening. Goiterous ventrolateral cervical swellings are evident by 1 week of age. Serum thyroid hormone and thyroid-stimulating hormone concentrations were low and high, respectively. Oral thyroid hormone replacement therapy restores near-normal growth and development. A nonsense mutation in the thyroid peroxidase gene causes the disorder. Reported as "commonly identified" in the TFT Health Survey. A genetic test is available.
Primary Lens Luxation (PLL) and Secondary Glaucoma: An autosomal recessive gene causes primary lens luxation. Homozygous affected dogs usually develop lens luxation between 4-8 years of age. Rarely, heterozygous carriers can develop lens luxation, but at a later age. Lens luxation can lead to secondary glaucoma and blindness. A genetic mutation has been identified, and a genetic test is available. OFA testing shows 28% carrier, and 2% affected.Elbow Dysplasia: Polygenic trait causing elbow arthritis. Too few Toy Fox Terriers have been screened by OFA to determine an accurate frequency.

Disease Predispositions
Cataracts: Too few Toy Fox Terriers have been CERF eye examined to determine an accurate frequency in the breed. Reported in 3.78% of Toy Fox Terriers presented to veterinary teaching hospitals.
Hypothyroidism: Inherited autoimmune thyroiditis. 3.0% positive for thyroid autoantibodies based on testing at Michigan State University. (Ave. for all breeds is 7.5%).
Food Allergies: Reported as "commonly identified" in the TFT Health Survey.
Heart Valve Problems: Can cause congestive heart disease. Identified by auscultation or echocardiogram. Reported as "commonly identified" in the TFT Health Survey.
von Willebrand's Disease (vWD): Mild bleeding disorder. Reported as "commonly identified" in the TFT Health Survey. A genetic test is not available for this breed.
Cryptorchidism (Retained Testicles): Can be unilateral or bilateral. Reported as "commonly identified" in the TFT Health Survey.
Eye Disorders: Too few Toy Fox Terriers have been CERF eye examined to determine accurate frequencies for eye disorders.
Deafness: Congenital deafness can be unilateral of bilateral. Diagnosed by BAER testing. Unknown mode of inheritance.
Demodicosis is also reported on the ATFTC website.

Isolated Case Studies
Immune-Mediated Diabetes Mellitus/Hemolytic Anemia: A four-year-old, spayed female toy fox terrier presented with hyperglycemia and severe anemia. A diagnosis of immune-mediated diabetes mellitus was made based upon the finding of beta-cell specific antibodies. Immune-mediated hemolytic anemia was diagnosed based on findings of a regenerative anemia, spherocytosis, hyperbilirubinemia, hemoglobinuria, and bilirubinuria. The anemia resolved following two months of immunosuppressive therapy. The diabetes was treated with insulin for four months, after which time treatment was no longer necessary.

Genetic Tests
Tests of Genotype: Direct test for Congenital Hypothyroidism is available from the Fyfe laboratory at Michigan State University: http://mmg.msu.edu/faculty/fyfe.htm (517-355-6463 x1559), HealthGene, and PennGen. Direct test for PLL is available from the OFA and Animal Health Trust.
Tests of Phenotype: Recommend patella evaluation, hip and elbow radiographs, CERF eye examination, cardiac evaluation, and thyroid profile including autoantibodies.

Miscellaneous
- Breed name synonyms: American Toy
- Registries: AKC, UKC, CKC, NKC (National Kennel Club).
- AKC rank (year 2008): 88 (731 dogs registered)
- Internet resources: American Toy Fox Terrier Club: www.atftc.com
Toy Fox Terrier Club of Canada: www.tftcc.ca