Mastiff Health Information Sheet       Click Here To Download A Printable Copy
Veterinary Insurance For Your Mastiffs? Click Here to Read/Print Article About Veterinary Health Insurance For Your Mastiffs!


In keeping with the spirit of the MCOA Code of Ethics, Mastiff breeders are encouraged 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 the MCOA Health Information 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.


Preferably buyers should be asked to read this before committing to a purchase and encouraged to ask questions. It is important that the buyer understand the potential for these conditions or problems to develop in any Mastiff, regardless of the line, pedigree, breeder, or testing of ancestors and thus the need for testing and reporting the results of those tests to the breeder and participating in ongoing research efforts.  Please keep in mind that all purebred & mixed breed dogs can have health concerns.


  • Cataract - Lens opacity that may affect one or both eyes and some forms may cause blindness.

  • 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 margins invert or roll inward, toward the eye causing eyelashes and hair to rub against the cornea which may result in ocular irritation.

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

  • 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. In Mastiffs the age at which PRA can be detected varies from as young as 6 months to as late as 42 months. Typically Mastiffs with PRA go blind gradually, first loosing their night vision and then their day vision. Many do not go completely blind until they are 8 years old or older.  There is a DNA test available through OptiGen for PRA in Mastiffs.

  • Retinal Dysplasia/Retinopathy also known as Canine Multi-focal Retinopathy (CMR) - Abnormal development of the retina present at birth and recognized to have three forms: folds, geographic, and detachment. A Mastiff with just folds will pass CERF and the folds may disappear over time while the geographic and detached forms may cause loss of vision or blindness.  There is a DNA test available though OptiGen for CMR in Mastiffs.


  • 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) on the affected limb.

  • Elbow Dysplasia - Elbow dysplasia encompasses several different conditions, all of which are indicative of abnormally formed or fused elbow joints and all can cause lameness and pain:

    • Fragmented Coronoid Process (FCP) - This form of elbow dysplasia is generally the most difficult to treat if the fragments are actually loose in the joint.

    • Osteochrondritis Dissecans (OCD) - A defect in the joint cartilage overlaying or attaching to the bone. OCD most commonly occurs in the elbows, shoulders, hocks and stifles.

    • Ununited Anconeal Process (UAP) - In giant breeds such as Mastiffs the Anconeal Process can close later than in smaller breeds, often as late as one year of age or older.

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

  • Hypertrophic Osteodystrophy (HOD) - A developmental disorder 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) – A developmental problem that affects the long bones during rapid growth periods typically between 6-16 months of age.  The exact cause is unknown although genetics, diet, stress, infection, and metabolic or autoimmune problems have been suspected.  Lameness can occur in one limb or over time in all limbs. It often is intermittent affecting one leg then another and back again…  It is self-limiting and spontaneously disappears.



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

  • Cystinuria - 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. Cystinuria in Mastiffs primarily affects males and can result in serious illness and may be life threatening.

  • Epilepsy – A seizure disorder which can have multiple causes. The age of onset of the inherited form is normally around 6 months to 5 years of age. Epilepsy is generally difficult to treat successfully in Mastiffs and other large breeds.

  • 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 other causes that we do not understand. Every Mastiff owner needs to familiarize themselves with bloat symptoms and have a plan of action to get the animal to an emergency medical facility at the onset of the first symptom. A dog that is bloating often has approximately 3 hours to live without medical intervention.

  • Heart Disease - The most common heart problems in Mastiffs 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.

  • 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 its function. Autoimmune thyroiditis is diagnosed by measuring the FT4D, cTSH & TgAA.  Acquired hypothyroidism can be caused by various problems such as stress for long periods of time, poor nutrition, prolonged infections, and chemical agents.

  • Spondylosis – is a degenerative disease that causes excessive bone production of osteophytes along the spinal vertebrae which can cause lameness.  In advanced cases the vertebrae can fuse together.  In many cases there are no clinical symptoms, but the acute expression of the disease such as lameness, severe pain and disabilities are often seen in adults and older Mastiffs.

  • 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.

  • Wobblers Syndrome – Cervical Vertebral Instability (CVI) is caused by pressure and pinching of the cervical spinal cord and the nerves in the neck due to ligament problems and/or vertebrae malformation. The compression on the spinal cord in the neck may cause the Mastiff to stand and move abnormally.  This is believed to be an inherited genetic disorder with environmental influence.  Rapid growth and nutrition may influence the expression of the disease.


Canine Health Information Center (CHIC) DNA Repository:

Please donate DNA for future Health Research & Testing

Orthopedic Foundation for Animals (800) 442-0418 e-mail:



Broad Institute of Harvard and MIT, Dog Genome Project,

7 Cambridge Center, Cambridge, MA  02142

Fax: (617) 324-2722, e-mail: website:

Printable Brochure:



Orthopedic Foundation for Animals (OFA), 2300 E. Nifong Blvd, Columbia, MO. 65201-3806

Phone: (573) 442-0418   Fax: (573) 875-5073 e-mail:

Cardiac: application:


Cystinuria Testing and DNA Research

Dr. Paula Henthorn, Cystinuria

Ryan Veterinary Hospital, Room 4027

University of Pennsylvania

3900 Delancey Street

Philadelphia, PA 19104-6010

Phone: (215) 898-8894


Epilepsy DNA Research

Canine Genetic Analysis Project (CGAP)

Anita Oberbaurer, PhD., Professor and Vice Chair

University of California, Davis Department of Animal Science

Phone: (530) 752-4997 Fax: (530) 752-0175 e-mail:


Canine Epilepsy Network

Liz Hansen, Coordinator of Veterinary Information

Dr. Gary Johnson's Lab - Department of Veterinary Pathology

College of Veterinary Medicine, University of Missouri

209 A Connaway Hall, University of Missouri, Columbia, MO 65211

Phone: (573) 884-3712   Fax: (573) 884-5414 e-mail:



Canine Eye Registration Foundation (CERF)

PO BOX 3007, Urbana, IL  61803-3007

Phone: (217) 693-4800 Fax: (217) 693-4801 e-mail:

OptiGen – DNA Tests

Progressive Retinal Atrophy (PRA) & Canine Multi-focal Retinopathy (CMR)

Cornell Business & Technology Park 767 Warren Road, Suite 300 Ithaca, New York 14850

Phone: (607) 257-0301   Fax: (607) 257-0353 e-mail: online application:


Hip and Elbow Dysplasia

Orthopedic Foundation for Animals (OFA), 2300 E. Nifong Blvd, Columbia, MO. 65201-3806

Phone: (573) 442-0418   Fax: (573) 875-5073 e-mail:

Hips:  Elbows:



PennHIP - University of Pennsylvania's Hip Improvement Program

3947 Chestnut Street, Philadelphia, PA 19104 website:

Phone: (215) 573-3176   e-mail:


Orthopedic Foundation for Animals (OFA), 2300 E. Nifong Blvd, Columbia, MO. 65201-3806

Phone: (573) 442-0418   Fax: (573) 875-5073 e-mail: application:


It should be noted that the use of soloxine (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 soloxine for at least 3 months prior to testing.


OFA Thyroid Information:

OFA Thyroid Application:


Recommended Lab - MSU

Diagnostic Center for Population and Animal Health, Canine Thyroid Registry

Michigan State University 4125 Beaumont Rd., Room 122 Lansing, MI  48910-8104

MSU Thyroid: MSU OFA Canine Thyroid Registry Information


von Willebrand's Disease (vWD)

AHDC, Cornell University College of Veterinary Medicine, Upper Tower Road, Ithica, NY 14853

Phone: 1-607-275-0622 Fax: 1-607-275-0720



Donate directly to AKC CHF Mastiff DAF. To make a tax deductible donation directly to the AKC Canine Health Foundation Mastiff Donor Advised Fund make checks payable to the AKC Canine Health Foundation and indicate "Mastiff DAF" in the notes section.

Include a note indicating that the funds are to go into the Mastiff Donor Advised Fund which is directed by the MCOA.  Mail the check to:

AKC Canine Health Foundation
PO Box 37941
Raleigh, NC 27627-7941

UPDATED: Mastiffs Issued CHIC Certificates in 2003 and 2004

Update Cystinuria Statistics - 3/04 OFA Preliminary Hip and Elbow

Evaluation Change 1/1/04

"In an effort to encourage open sharing of health test results, beginning January 2004, the OFA will publish preliminary (under 24 months) hip and elbow results on the OFA website IF the owner has initialed the authorization block to release all results (including abnormal results)."

Mastiff Health Information Sheet

The MCOA Health Committee recommends that all Mastiff breeders provide their puppy buyers with a list of health problems found in Mastiffs. If you are considering getting a Mastiff, please follow the link above and print out the Mastiff Health Information Sheet and review it first.

Mastiff Health Fundraisers

Help support cancer, epilepsy, cruciate ligament rupture and cystinuria research!

CERF Statistics for 2003

This information is provided by CERF and may not be reproduced without CERF's explicit written permission.

Mastiffs passing CERF in 2003

  • CERF Statistics Report for Eye Disease 2002 and 2003

Mastiffs to Participate in Lymphoma and Osteosarcoma Research

 If you have a Mastiff diagnosed with Lymphoma or Osteosarcoma please consider participating in this new research being funded in part by the MCOA. For more details about how to particiapte please click on the following link: Participants Needed for Research on Canine Cancer.

CHIC - Canine Health Information Center

The Canine Health Information Center (CHIC) was started by the Canine Health Foundation's (CHF) in cooperation with Orthopedic Foundation for Animals (OFA). CHIC is developing a database which will serve as an information resource for researchers, breeders and dog owners. The CHIC Criteria for Mastiffs developed with the OFA and approved by the MCOA Board are listed below. The OFA mailed out the first 150 CHIC Certificates in June 2001.

For more information check out the CHIC web site at:

The following four criteria are mandatory:

  • Hip Dysplasia OFA, OVC, or GDC hips. OFA, OVC, GDC hips to be based on x-rays taken at, or after, 24 months of age.

  • Elbow Dysplasia OFA, OVC, or GDC elbows. OFA, OVC, GDC elbows to be based on x-rays taken at, or after, 24 months of age.

  • Heart OFA heart, at 12 months or older.

  • Eyes CERF certified at or after 24 months of age. Yearly recertification recommended.

The following two to be optional:

  • Thyroid MSU or other lab's equivalent full thyroid panel and/or OFA Thyroid Certification at or after 24 months of age. Yearly recertification recommended. For tests other than OFA, the following must be included:

  • Free T4 by dialysis (FT4D)

  • Canine Thyroid Stimulating Hormone (cTSH) Thyroid globulin Autoantibody (TgAA)

  • T3 & T4 Autoantibodies

  • Lab interpretation Lab must be one of those approved by OFA



UPenn cystinuria at or after the age of 18 months.

The evaluation at the oldest age is the one that will be recorded. For instance, if a dog is certified at 24 months, then is later (at 30 months) evaluated by the same or other agency, then the 30 month evaluation would be recorded in CHIC.

Permanent identification at the time of testing (tattoo, microchip or DNA) is a CHIC requirement.

For failing results from open databases: Should the owner decide to send in information that meets the requirements for a CHIC certificate and some of the results are from an open database and are not normal (e.g. mild hip dysplasia, heart condition, etc.), the mastiff and owner will still receive a certificate and the failing results will be listed on the certificate and anywhere that the certificate is published.

PRA News

  • PRA DNA Testing Clinics - Refunds and Discounts

  • Mastiff PRA DNA Test Now Available thru OptiGen

  • Transcript of Dr. Acland's Seminar

  • Mastiff PRA Gene Found!

  • Second Meagle Diagnosed With PRA

  • Significant Development in Mode of Inheritance Study Murphy, one of the "Meagles", has been diagnosed with PRA. Click on the link above to read more. Also read Thoughts on Murphy by Jane Walsh.

  • MCOA Health Poster Wins 1st Prize at CHF Conference 

Health News

  • CHF 1999 Health Symposium Summary

  • Canine Eye Registration Statistics for the Year 1999

  • von Willebrand in Mastiffs

Future Dog: Breeding for Genetic Soundness

Book by Patricia J. Wilkie, Phd. sold thru the Canine Health Foundation with profits going to support research. An excellent, up to date source of information about genetic principals and their applications in dog breeding. You can order it online at the CHF Store, or by calling the CHF at 1-888-682-9696.

Canine Health Foundation Parent Club Partnership Program

The MCOA Board has voted to join the Canine Health Foundation Parent Club Partnership Program. This will allow the MCOA to take advantage of the CHF's tax exempt fund for donations, matching funds, research proposal help, and review of grants. There are various requirements when using the tools. For more information check out the Canine Health Foundation Web Site at

Health Committee

What is the purpose of the MCOA Health Committee? We are pooling the resources of the groups working on individual health problems providing support and dialog, tracking health problems in all Mastiffs, encouraging all Mastiff owners to participate in health testing, keeping an eye on research, interfacing with the Canine Health Foundation, and helping to keep Mastiff owners and breeders informed of new developments and opportunities with respect to Health problems relevant to Mastiffs. Today, we are seeing more and more new research being done where information is needed by researchers in the form of histories, pedigrees and/or DNA samples. New tools for detecting or tracking health problems and, new methods for treating problems are being developed.

We cannot make progress without you, we need your help and support in many ways: providing information to the MCOA GDC both positive and negative, answering Health Surveys, donating information and DNA to various research efforts, become a part of the Committee, letting us know your thoughts and ideas, and sometimes donating time and money to raise funds for research. Are you interested in a particular health problem? Are you willing to research it, write articles, help gather information? If you can help, please get in touch with one of us, we look forward to hearing from you.

MCOA Health Committee:
Anna May (951) 704-6022  
Jenny Zinn-Boyce (562) 425-8354    


Jan McNamee (330) 648-9427 
Dr. Bill Newman (814) 623-9377  

Subcommittee chairs:

Cancer - Jenny Zinn-Boyce (562) 425-8354
Cystinuria - Anna May (951) 704-6022
DNA - Mary DeLisa (303) 929-5529
Health Awards - Karen Flocker (480) 632-5240
Hip - Elbow Dysplasia  Tammy Sholes (828) 428-3355
PRA - Carla Sanchez (951) 696-4169
Seizure Disorders - Doreen Dysert (503) 348-9347