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This disclosure should be read by anyone contemplating acquiring a Mastiff. It is presented here to inform puppy buyers of developmental conditions, that may or may not be hereditary or genetic, that are known to exist in Mastiffs, as well as methods to test and/or monitor some of these conditions.

It is hoped this Fact Sheet will guide buyers to ask pertinent questions, encourage their review of testing certifications and enable them to make educated decisions before purchasing a Mastiff. Buyers are asked to read and sign this "disclosure" before commiting to a purchase from MCOA members, thereby signifying the buyer understands the potential for these conditions or problems to develop in any Mastiff, regardless of the line, pedigree, breeder, or testing of ancestors.


Cataract -
     Lens opacity that may in part or in total affect one or both eyes. Blindness results
     when cataracts are complete and in both eyes.

Distichiasis -
     Eyelashes abnormally located in the eyelid margin which may cause ocular irritation.

Ectropion -
     Conformational defect resulting in eversion of the eyelids, which may cause ocular
     irritation due to exposure.

Entropion -
     Conformational defect where eyelid margin inverts, or rolls inward, toward the eye causing
     eyelashes and hair to rub against the cornea resulting in ocular irritation.

Macroblepharon -
     Abnormally large eyelid opening; may lead to secondary conditions associated with corneal

Persistent Pupillary Membranes (PPM) -
     Persistent blood vessel remnants in the anterior chamber of the eye which fail to regress
     normally in the neonatal period.

Progressive Retinal Atrophy (PRA) -
     Degenerative disease of the retinal visual cells which leads to blindness.

Retinal Dysplasia -
     Abnormal development of the retina present at birth and recognized to
     have three forms: folds, geographic, detachment.


Hip Dysplasia -
     Hip dysplasia is a painful condition caused by abnormally formed hips. The animal becomes lame
     in the hind quarters due to the pain associated with the degeneration of the hips.

Elbow Dysplasia -
     Elbow dysplasia encompasses several different conditions, all of which are indicative of
     abnormally formed or fused elbow joints and all can result in lameness and pain for the animal:

Hypertrophic Osteodystrophy (HOD) -
     A nutritionally based developmental disease that manifests with toes turning in or out,
     roached toplines, pinched rears, and in advanced stages fever, lethargy, pain in joints,
     inability to stand or function. This is a problem of intake in calories versus output
     of energy - too many calories consumed and/or unbalanced diet disrupted by supplementing.

Panosteitis (Pano or Wandering Lameness) -
     Another nutritionally based developmental problem associated with too rapid growth.
     Lameness can occur in one limb or over time in all limbs. It is self-limiting and
     spontaneously disappears.

Anterior Cruciate Ligament (ACL) Rupture -
     The knee along with the external support (i.e., collateral leg) has two ligaments
     inside the joint that help prevent forward movement (i.e., cruciate). Insult/injury can
     cause this ligament to rupture and result in acute lameness (the animal will not want
     to bear weight) in the affected limb.


von Willebrand's disease (vWD) -
     An abnormal bleeding disorder due to a lack of normal clotting. An animal's life can be threatened
     by bleeding due to an injury, or during spaying/neutering or any other condition
     resulting in bleeding.

Heart Disease In Mastiffs -
     The most common heart problems are aortic stenosis, mitral valve dysplasia and cardiomyopathy.
     Early detection and treatment are essential for a good prognosis. Some mastiffs
     have heart murmurs that are mild and not a cause for concern. If a heart murmur is detected it
     is essential to have it checked to see if it is an "innocent" murmur or a serious problem.

Cystinurnia -
     (from Dr. Giger's description of Cystinuria): Cystinuria is an inherited metabolic disease caused
     by a defective kidney transporter for cystine and some other amino acids. Because cystine
     readily precipitates in acid urine crystals and later calculi (stones) can form in
     the kidney and bladder. These calculi can result in serious illness, especially in males.
     Cystinuric animals may show recurrent clinical signs of a urinary tract disorder from a
     few months of age until late in life.

Hypothyroidism -
     Hypothyroidism is the result of an abnormally functioning thyroid gland resulting in a
     lower than normal level of thyroid hormone. This lack of thyroid hormone can have serious health
     consequences including coat and skin problems, intolerance to cold, weight gain or loss,
     infertility, sudden aggression, and immune system malfunctions. The inherited form
     is autoimmune thyroiditis where the body's own immune system attacks and destroys the
     thyroid gland or reduces it's function. Acquired hypothyroidism can be caused by various problems
     such as stress for long periods of time, poor nutrition, prolonged infections, and chemical agents.

Cancer -
     Most forms of cancer have been diagnosed in some members of the breed. Probably some forms
     of cancer hereditary while others occur spontaneously or even due to environmental toxins.

Gastric Dilation, Torsion, Volvulus (Bloat) -
     Bloat is a hideous killer of giant breed animals, and Mastiffs are no exception. Without warning,
     the stomach fills with air (dilation), can twist 180 degrees (torsion) on its long axis,
     or more than 180 degrees (volvulus) thereby cutting off blood and oxygen to vital organs.
     Bloat can be primary or secondary, caused by emotional or physical stress, improper nutrition
     or feeding habits, guzzling water, inappropriate exercise, as well as many other causes that
     we do not understand. Every Mastiff owner needs to familiarize themself with bloat symptoms and
     have a plan of action to get the animal to emergency medical facilies at the onset of the first
     symptom. The animal that is in bloat has approximately 3 hours to live and without medical
     intervention they will certainly die.


Canine Eye Registration Foundation (CERF)
1248 Lynn Hall
Purdue University
West Lafayette, IN 47906
(765)-494-8179 fax: (765)-494-9981

Diagnostic Laboratory
College of Veterinary Medicine,
Cornell University
Upper Tower Road
Ithica, NY 14851

Animal Health Diagnostic Laboratory
P.O. Box 30076
Lansing, MI. 48909

     It should be noted that the use of siloxine (used to treat hypothyroidism) makes the
     results of thyroid testing invalid. For a thyroid test to be valid the mastiff being tested must
     not have had any siloxine for at least 3 months prior to testing.

Hip and Elbow Dysplasia:
Institute for Genetic Disease Control
P.O. Box 222, Davis, CA 95617
Phone/Fax (530) 756-6773

Synbiotics Corporation

11011 Via Frontera
San Diego, CA 92127
858- 451-3771 Fax: 858-451-5719

Orthopedic Foundation for Animals, Inc (OFA)
2300 E. Nifong Blvd.
Columbia, MO. 65201-3856
tel. (314)442-0418
Fax. (314)875-5073

Hip Dysplasia DNA Research (cheek swab):
Vet Gen Hip Dysplasia Research (cheek swab)
Cheryl Hogue, Research Coordinator
1-800-4-VETGEN fax: (734)669-8441

     It should be noted that raising dogs on glucosamine/ cosequin/adequan can skew the results
     of testing, possibly making the results appear better than they would have been
     without supplementation and potentially masking the true phenotype of the dog.

Cardiac, Thyroid and Patellas:
Orthopedic Foundation for Animals, Inc (OFA)
2300 E. Nifong Blvd.
Columbia, MO. 65201-3856
tel. (314)442-0418
Fax. (314)875-5073

Cystinuria Testing and DNA Research:
Dr. Urs Giger / Cystinuria
Veterinary Hospital, University of Pennsylvania
3850 Spruce Street, Philidelphia, PA 9104-6010
Secretary: 215-898-8880

Mastiff PRA DNA Research (blood):
Retinal Disease Studies Facility
New Bolton Center
University of Pennsylvania

382 West Street Road
Kennett Square, PA 19348
(610) 925 8112 fax (610) 444-1361

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