Parson Russell terrier health testing and hereditary health issues

The Parson Russell terrier is a small terrier dog that was originally developed in the 18th century by Parson John “Jack” Russell. As the name implies, the Parson Russell terrier is a close relative to the Jack Russell, and in fact the Parson Russell was originally classed as the show type of the Jack Russell breed, only gaining recognition as a breed in its own right in 1990.

The Parson Russell terrier shares a great many similarities with the Jack Russell, but they tend to be slightly larger and longer legged. They can stand up to 14” tall at the withers, and weigh up to 7.7kg, with males of the breed tending to be larger than females. The breed’s coat is mainly white, with tan, black or tricolour markings, and their coats can be either smooth, rough or broken.

The Parson Russell terrier is a plucky, lively and energetic little dog that is bold, feisty and outgoing. Not prone to shyness with either people or other dogs, they can be somewhat stubborn and have something of a tendency to being dominant if not correctly trained and handled, but are a popular, versatile dog that makes for a good pet.

If you are wondering if the Parson Russell terrier is the right choice of dog for you, it is of course important to do plenty of research into the breed before committing to a purchase. As part of this, it is wise to find out about the hereditary health of the breed as a whole, including if they have a genetic predisposition to any hereditary health issues that may affect their lifespan or quality of life.

We will cover these factors in more detail within this article.

Parson Russell terrier longevity

The average lifespan of the Parson Russell terrier is 14-15 years, which places the breed average well above the normal lifespan rankings across the board for all dog breeds of a similar size and build. This indicates that the Parson Russell terrier is as a general rule a healthy and robust dog, which is not prone to developing or inheriting a wide range of health conditions that might reasonably be expected to shorten their lifespans.

Parson Russell terrier genetic diversity

The coefficient of inbreeding statistic for the Parson Russell terrier is 10%, which indicates that a relatively high degree of inbreeding takes place across the breed in order to maintain breed lines. While this is in some ways necessary to the ongoing development of the breed, widespread inbreeding can lead to a greater incidence rate of hereditary health problems, as well as problems such as smaller litter sizes and a higher level of foetal mortality.

The ideal accepted norm for the coefficient of inbreeding for pedigree breeds is 6.25%, and Parson Russell terrier owners are advised to reduce the coefficient of inbreeding statistic within their own breed lines where possible.

Health testing for the Parson Russell

The British Veterinary Association and The Kennel Club monitor the health of all pedigree dog breeds, and for most breeds, recommend participation in certain health schemes and testing programmes in order to monitor and improve the ongoing health of the breed. For the Parson Russell terrier, the following pre-breeding tests and screening schemes are in place:

• Testing for primary lens luxation of the eye, a condition that can cause pain and the development of glaucoma. DNA testing is also available for primary lens luxation.
• DNA testing for late onset ataxia.
• DNA testing for spinocerebellar ataxia, or SCA.
• Parson Russell terrier breed clubs also advise testing for patellar health, and hereditary deafness.

Other health issues within the breed

As well as the conditions above that can be screened or tested for in parent dogs prior to making the decision to breed, a small range of other health conditions can also present within the Parson Russell terrier, but for which no pre-breeding screening is currently offered.

While the Parson Russell terrier is not a breed that tends to be sickly or widely afflicted with problems, potential buyers are advised to make themselves aware of the following conditions:

• Cataracts of the eyes, particularly in old age. While cataracts may have a hereditary element to them, they are usually operable in order to preserve the dog’s vision.
• Various types of cancers, again most commonly in old age. The most prevalent type of cancer across the breed as a whole is histiocytoma.
• Patellar luxation, a condition that affects the kneecaps. This condition leads to the kneecaps of one or both legs slipping and dislocating, due to the ligaments that hold the kneecaps in place being too weak to properly secure them.
• Urine crystals and stone formation, particularly in male dogs.
• Deafness, related to the pigmentation of the inner ear of in certain breed lines of Parson Russell terriers.