Animalia Life

The Breed History
This particular mastiff breed is first recorded in Britain around 1860. Like the Old English Mastiff (Syn. Mastiff), it is one of many mastiff-type dogs that originated from ancient Asian stock. The cross of 60% English Mastiff with 40% English Bulldog produced this breed. In 1924, the English Kennel Club first recognized Bullmastiffs as a breed, and in 1933-34, the AKC also recognized this breed.

Breeding for Function
To protect estates from poachers, the bulldog-mastiff type was ideal. They were silent workers, following a human trail by odor, and when pinned down, did not maul their intruders but just held them. Later, they became very popular as guarding and watchdogs.

Physical Characteristics
Height at Withers: female 24-26" (61-66 cm), male 25-27" (63.5-68.5cm).
Weight: females 100-120 lb (45.5-54.5 kg), males 110-130 lb (50-59 kg).
Coat: The short, very dense haircoat is acceptable in fawn, red and brindle. Only a very small white marking on the chest is acceptable. Longevity: 9-10 years
Points of Conformation: The Bullmastiff is smaller and more compact, with more of a bulldog type head than the English Mastiff. This alert powerful dog is about as long as tall. The skull is large, with a well-wrinkled forehead when alert. Eyes are medium-sized and dark colored, and ears are triangular and carried close to the head; set high. They possess a moderate stop, and the muzzle is deep and broad with dark coloration. Nose is black and large, and the flews moderately pendulous. The neck is moderate in length and arch, with well-developed musculature. The topline is level, and the thorax is wide and deep, with well-sprung ribs. The tail is high set and tapers to end at the tarsus; it is straight/slightly curved. Limbs are heavily boned and straight, feet are medium sized with well-arched toes, black nails and thick pads. The Bullmastiff moves with a ground-covering smooth stride.

Recognized Behavior Issues and Traits
Reported breed attributes include: Gentle, self assured, courageous, sensitive to temperature extremes, intelligent, and some are a bit overprotective and may resist obedience training. Very aloof with strangers so early socialization and obedience training is important. Low to moderate exercise needs, good for town or country, low grooming needs, moderate shedders, and have a high drooling and snoring tendency. Good dog for experienced dog handlers.

Normal Physiologic Variations
35% of Bullmastiff litters are delivered by C-section according to a UK study.1

Drug Sensitivities
None reported

Inherited Diseases
Hip Dysplasia: Polygenically inherited trait causing degenerative joint disease and hip arthritis. OFA reports 24.5% affected.
Elbow Dysplasia: Polygenically inherited trait causing elbow arthritis. OFA reports 13.8% affected. Reported 38.9x odds ratio for the fragmented coronoid process form of elbow dysplasia versus other breeds.
Progressive Retinal Atrophy (PRA): An autosomal dominant form of PRA occurs in the breed, with an onset of 6 months to 4 years of age. A genetic test is available.
Patella Luxation: Polygenically inherited laxity of patellar ligaments, causing luxation, lameness, and later degenerative joint disease. Treat surgically if causing clinical signs. Too few Bullmastiffs have been screened by OFA to determine an accurate frequency.
Multifocal Retinopathy/Retinal Dysplasia: Autosomal recessive retinal pigment epithelial dysplasia causing localized multifocal retinal detachments. Age of onset from 11 to 13 weeks of age. Reported in 5.26% of Bullmastiffs CERF examined by veterinary ophthalmologists between 2000-2005. A genetic test is available.
Glomerulonephropathy: Rare disorder, where affected dogs present between the ages of 2.5 and 11 years with clinical and laboratory signs of chronic renal failure. Histopathology shows chronic glomerulonephropathy with sclerosis. Pedigree analysis supports an autosomal recessive mode of inheritance.
Cerebellar Ataxia with Hydrocephalus: Rare disorder, where affected puppies have ataxia, hypermetria, conscious proprioceptive deficits, behavioral abnormalities, and a visual deficit. Brain MRI shows symmetric hydrocephalus and focal areas of increased signal intensity within the central nuclei of the cerebellum. Histopathological findings are vacuolation, gliosis and axonal degeneration within the deep cerebellar nuclei. This disorder is most likely inherited in an autosomal recessive manner.

Disease Predispositions
Entropion: Rolling in of eyelids, often causing corneal irritation or ulceration. Entropion is reported in 7.12% of Bullmastiffs CERF examined by veterinary ophthalmologists between 2000-2005.
Hypothyroidism: Inherited autoimmune thyroiditis. 5.8% positive for thyroid auto-antibodies based on testing at Michigan State University. (Ave. for all breeds is 7.5%).
Distichiasis: Abnormally placed eyelashes that irritate the cornea and conjunctiva. Can cause secondary corneal ulceration. Identified in 4.02% of Bullmastiffs CERF examined by veterinary ophthalmologists between 2000-2005.
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 3.10% of Bullmastiffs CERF examined by veterinary ophthalmologists between 2000-2005, with 1.55% being iris to cornea.
Ectropion: A rolling out of the eyelids, that can cause tear pooling, conjunctivitis, and frequent infection. Can be secondary to macroblepharon; an abnormally large eyelid opening. Ectropion is reported in 3.10%, and macroblepharon in 2.79% of Bullmastiffs CERF examined by veterinary ophthalmologists between 2000-2005.
Osteochondritis Desicans (OCD): Polygenically inherited joint cartilage defect. Causes joint pain and lameness in young growing dogs. Mild cases can resolve with rest, while more severe cases require surgery. Reported 85.9x odds ratio for hock OCD, and 6.7x odds ratio for shoulder OCD versus other breeds.
Cranial Cruciate Ligament Rupture (ACL): Traumatic tearing of the anterior cruciate ligament. Dorn reports a 2.80x odds ratio in Bullmastiffs versus other breeds. Treatment is surgery.
Cataracts: Capsular cataracts predominate, though anterior, posterior, and nuclear cataracts also occur in the breed. Identified in 2.79% of Bullmastiffs CERF examined by veterinary ophthalmologists between 2000-2005. CERF does not recommend breeding any Bullmastiff with a cataract.
Gastric Dilatation-Volvulus (bloat, GDV): Polygenically inherited, life-threatening twisting of the stomach within the abdomen. Requires immediate treatment. Reported at an increased frequency in the breed.
Dilated Cardiomyopathy (DCM): Dilated cardiomyopathy causing heart failure is identified in the breed. Unknown mode of inheritance.
Cystine Urinary Calculi: Bullmastiffs are a breed with increased risk of developing cystine calculi, due to an abnormality of cystine metabolism.
Lymphoma/Lymphosarcoma: Malignant cancer of lymphoid tissue. An increased prevalence is seen in the breed. In one study, a large family of Bullmastiffs was identified, where 15% of the dogs developed lymphosarcoma over a three year period.
Optic Nerve Hypoplasia: A congenital defect of the optic nerve which causes blindness and abnormal pupil response in the affected eye. CERF does not recommend breeding affected dogs. Identified in 1.57% of Bullmastiffs CERF examined by veterinary ophthalmologists between 1991-1999, though none were reported between 2000-2005.
Calvarial Hyperostotic Syndrome (CHS): A clinical syndrome is identified in young male Bullmastiffs of progressive and often asymmetric cortical thickening of the calvaria with irregular, bony proliferation over the frontal, temporal, and occipital bones. Osteopathy is diagnosed based on radiographs and biopsy. In 80% of the cases presented, the lesion is self-limiting.
Oligodendroglial Dysplasia (Spinal Cord Leukodystrophy): Affected Bullmastiffs show a young adult onset, slowly progressive, moderate to severe ataxia of all limbs, spastic tetraparesis that is worse in the pelvic limbs, and a diffuse, action-related, whole-body tremor. Histopathological lesions include white matter myelin plaques, and proliferation of oligodendroglial processes.
Anasarca, Cervical Vertebral Instability, Epilepsy, Panosteitis, Seasonal Flank Alopecia, and Supernumerary Teeth are reported.

Isolated Case Studies
Craniomandibular Osteopathy (CMO): A 6-month-old bullmastiff was presented with bilateral painful swellings of the mandible. Craniomandibular osteopathy was diagnosed based on radiographs and biopsy. The condition resolved with palliative care.20 Primary Ciliary Dyskinesia: A 2.5-year-old male Bullmastiff with a history of chronic bronchopneumonia and chronic rhinitis was found to have primary ciliary dyskinesia. Diagnostic evaluations included tracheal mucociliary clearance, functional and ultrastructural ciliary examination, induction of ciliogenesis in cell culture, and sperm evaluation.
Juvenile Renal Dysplasia: A 15-week-old female Bull Mastiff which presented with clinical signs of chronic renal failure. Renal dysplasia and concurrent pyelonephritis were diagnosed by ultrasound, clinical pathology, and biopsy.
Muscle Tumors: Primary skeletal muscle lymphoma and muscle hemangiosarcoma have been diagnosed in individual case studies of Bullmastiffs.
Medulloepithelioma: A 6-month-old Bullmastiff presented with clinical signs of incomplete upper motor neuron transverse myelopathy involving the hindlimbs. An embryonal medulloepithelioma was found involving the L1 spinal cord.
Lymphangiosarcoma: A 3.5-year-old Bullmastiff presented with vaginal bleeding 3 weeks after cessation of estrus, during which intromission by the male had been unsuccessful. During ovariohysterectomy a large multi-cystic, proliferative, spongy, fluid-filled, brownish-red mass surrounding the cervix and projecting into the abdominal space was removed with the cervix. Histopathology revealed malignant lymphangiosarcoma that had invaded into the surrounding tissues.

Genetic Tests
Tests of Genotype: Direct tests for PRA and Multifocal Retinopathy are available from Optigen.
Tests of Phenotype: CHIC certification: Required testing includes hip and elbow radiographs, CERF eye examination, congenital cardiac evaluation (by a cardiologist or by echocardiography), and thyroid profile including autoantibodies. Optional tests include direct test for PRA, and kidney tests. (See CHIC website; caninehealthinfo.org). Recommend patella evaluation.

Miscellaneous
- Breed name synonyms: Gamekeeper’s Night Dog (historical).
- Registries: AKC, UKC, CKC, KCGB (Kennel Club of Great Britain), ANKC (Australian National Kennel Club), NKC (National Kennel Club).
- AKC rank (year 2008): 39 (3,447 dogs registered)
- Internet resources: American Bullmastiff Association: bullmastiff.us/
Bullmastiff Fanciers of Canada: bmfc.ca
British Bullmastiff League: britishbullmastiffleague.com