Animalia Life

The Breed History
The Bull-and-Terrier (white English terrier X Bulldog) was the progenitor of the miniature version of the bull terrier. Additional crosses with the Spanish terrier and the Black and Tan may have also contributed to the final type. Some records show Dalmation crosses also occurred. The goal was to produce the miniature version of the bull terrier. AKC accepted this breed in 1991.

Breeding for Function
These downsized bull terriers were not specifically bred for fighting as were their larger counterparts, but they have inherited the feisty courageous personality from their forbearers. This makes them a formidable watchdog.

Physical Characteristics
Height at Withers: 10-14" (24.5-35.5 cm)
Weight: 24-33 lb (11-15 kg)
Coat: They possess a short hard glossy flat haircoat either white or colored, with or without markings.
Longevity: 12-13 years
Points of Conformation: A sturdy square constitution characterizes the breed. The skull is full, the forehead flat and egg-shaped as in the bull terrier. The small triangular shaped obliquely set eyes are dark in color and deep set, resulting in a piercing look. High set ears are close set, small and pricked when alert, and the leather is moderate. The nose is black. The neck is long, arched and muscular, not throaty. The back is short with a moderate arch over the loin. The chest is very broad, and the thorax is deep with the broadness and depth extending well back in the rib cage. They have a moderate abdominal tuck, and the tapering fine curved tail is set low and carried high. Limbs have straight heavy bone and moderate musculature. The small compact feet have well knuckled up toes.

Recognized Behavior Issues and Traits
Reported breed attributes include: Though fiery if faced with opponents, in the home they are expected to be tractable. Courageous, playful, devoted, tenacious, generally friendly but need an early introduction to children (and small pets or other dogs) in the household. Needs human companionship, has low grooming needs and is a low shedder. Good in town or country but has high energy levels so adequate exercise and mental gymnastics are recommended to prevent boredom vices.

Normal Physiologic Variations
According to a study in the UK, 52.4% of Miniature Bull Terrier litters are delivered via cesarean section.

Drug Sensitivities
None reported

Inherited Diseases
Primary Lens Luxation: An autosomal recessive lens luxation occurs in the breed due to abnormalities of the suspensory apparatus of the lens (zonule). Often progresses to secondary glaucoma. Relative risk of 48.44x versus other breeds. Identified in 3.88% of Miniature Bull Terriers CERF examined by veterinary ophthalmologists between 2000-2005. Reported at a frequency of 6.33%, and glaucoma at a frequency of 3.80% in the 2002-2004 MBTCA Breed Health Survey. 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. A genetic test is available from OFA, showing 52% carrier, and 13% affected.
Hip Dysplasia: Polygenically inherited trait causing degenerative joint disease and hip arthritis. Too few Miniature Bull Terriers have been screened by OFA to determine an accurate frequency.
Patella Luxation: Polygenically inherited laxity of patellar ligaments, causing luxation, lameness, and later degenerative joint disease. Treat surgically if causing clinical signs. Too few Miniature Bull Terriers have been screened by OFA to determine an accurate frequency.
Elbow Dysplasia: Polygenically inherited trait causing elbow arthritis. Too few Miniature Bull Terriers have been screened by OFA to determine an accurate frequency.
Hereditary Nephritis: Autosomal dominant disorder causing renal failure at variable ages in affected dogs due to abnormal kidney basement membrane protein and structure. No genetic test is available.

Disease Predispositions
Persistent Pupillary Membranes: Strands of fetal remnant connecting; iris to iris, cornea, lens, or involving sheets of tissue. The later three forms can impair vision, and dogs affected with these forms should not be bred. Identified in 11.34% of Miniature Bull Terriers CERF examined by veterinary ophthalmologists between 2000-2005.
Hypothyroidism: Inherited autoimmune thyroiditis. 4.5% positive for thyroid auto-antibodies based on testing at Michigan State University. (Ave. for all breeds is 7.5%).
Deafness: Congenital deafness can be unilateral or bilateral. Diagnosed by BAER testing. Reported at a frequency of 3.80% in the 2002-2004 MBTCA Breed Health Survey. Unknown mode of inheritance.
Corneal Dystrophy: Endothelial form occurs in the breed due to the edema from the loss of the inner lining of the cornea. Results in keratitis and decreased vision. Identified in 1.49% of Miniature Bull Terriers CERF examined by veterinary ophthalmologists between 2000-2005.
Vitreous Degeneration: Liquefaction of the vitreous gel which may predispose to retinal detachment. Identified in 1.49% of Miniature Bull Terriers CERF examined by veterinary ophthalmologists between 2000-2005.
Cataracts: Anterior cortex and capsular punctate cataracts predominate in the breed. Identified in 1.19% of Miniature Bull Terriers CERF examined by veterinary ophthalmologists between 2000-2005. CERF does not recommend breeding any Miniature Bull Terrier with a cataract.
Left Ventricular Outflow Tract Obstruction (LVOTO): Reported as a problem in the breed. Screen by echocardiography. The MBTCA recommends only breeding dogs with LVOT rates of less than 2.2 m/ sec with no multiple minor or any major structural defects present.
Compulsive Tail Chasing and Spinning: Disorder of persistent spinning observed in the breed. Possibly a behavioral compulsion, as 75% of affected dogs respond to clomipramine administration. However a neurological partial seizure disorder cannot be ruled out, as some dogs have abnormal electroencephalograms and respond to anticonvulsants.

Isolated Case Studies
None reported

Genetic Tests
Tests of Genotype: Direct genetic test for Lens Luxation is available from OFA and AHT.
Tests of Phenotype: CHIC Certification: Required testing includes cardiac evaluation with echocardiogram, CERF eye examination, BAER test for deafness, and kidney disease screening with urine protein:creatinine ratio. Recommended tests include hip and elbow radiographs, patella examination, and thyroid profile including autoantibodies.

Miscellaneous
- Breed name synonyms: Mini Bull
- Registries: AKC, UKC, CKC, KCGB (Kennel Club of Great Britain), ANKC (Australian National Kennel Club), NKC (National Kennel Club)
- AKC rank (year 2008): 124 (236 dogs registered)
- Internet resources: Miniature Bull Terrier Club of America: www.minibull.org
Miniature Bull Terrier Club UK: www.miniaturebullterrierclub.co.uk
Miniature Bull Terrier Club of Canada: www.minibullyclub.com