Tag Archives: skull shape

Skull shape and its implication for animal welfare

Syringomyelia (SM) is a painful condition in dogs that is more common in toy breeds like the Chihuahua and the Cavalier King Charles Spaniel. It involves the formation of fluid-filled cavities, known as syrinxes, in the spinal cord.  In these toy breeds, SM is usually secondary to a specific malformation of the skull called Chiari-like Malformation, CM for short.

Cavalier King Charles Spaniel

New research conducted at the University of Bristol’s School of Veterinary Sciences has identified two significant risk factors associated with these painful neurological conditions.

Identifying a head shape in dogs that is associated with these diseases would allow for selection away from these conditions and could be used to further breeding guidelines. Dogs were measured in several countries using a standardised “bony landmark” measuring system and photo analysis by trained researchers.

The researchers found two significant risk factors associated with CM/SM in the skull shape of the Cavalier King Charles Spaniel.  These were the extent of the broadness of the top of skull relative to its length, also known as brachycephaly, and the distribution of doming of the skull. The study suggests that brachycephaly, with resulting doming towards the front of the head, is associated with both conditions.

Thomas Mitchell, who was the undergraduate involved in the study, says “The study also provides guidance to breed clubs, breeders and judges that have a responsibility to avoid obvious conditions or exaggerations which would be harmful in any way to the health, welfare or soundness of the breed.  It will also provide vets with verified advice to provide to breeders outside the show ring and to occasional hobbyists.”

This research has been published online in the journal Canine Genetics and Epidemiology.

Source:  University of Bristol media release

Please also see my earlier post on Your dog may have a permanent headache, which discusses the Chiari malformation and earlier research on the Griffon Bruxellois.

Kathleen Crisley, specialist in dog massage, rehabilitation and nutrition/food therapy, Canine Catering Ltd, Christchurch, New Zealand

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Short dog syndrome

You’ve probably heard about Short Man Syndrome.  (In fact, many of us (including me) have experienced it firsthand!)

Did you know that there is growing evidence of Short Dog Syndrome?

Researchers at the University of Sydney have published their research into this topic in the online journal PLoS One.  Professor Paul McGreevy is the lead author of the study and says, “the shorter the dogs the less controllable their behaviour is for their owners.”

Dachshunds and other short breed dogs may be more difficult to train and control

Dachshunds and other short breed dogs may be more difficult to control

The study used owners’ reports on the behaviour of over 8,000 dogs from across 80 breeds and related them to the shape of 960 dogs of those breeds, revealing strong relationships between height, bodyweight, skull proportions (relative width and length) and behaviour.

33 out of 36 undesirable behaviours were associated with height, bodyweight and skull shape

As a breed’s average height decreased, the likelihood of behaviors such as mounting humans or objects (humping), owner-directed aggression, begging for food and attention-seeking increased.

“The only behavioral trait associated with increasing height was ‘trainability’. When average bodyweight decreased, excitability and hyperactivity increased,” said Professor McGreevy.

The researchers admit that there is an aspect here of nature vs nurture.  If aggressive and ‘bad’ behaviours were present in larger dogs, the results could be more dangerous.  Poor behaviour in small dogs is likely to be tolerated more.  Over time, breeding has resulted in the patterns observed by the research team.

Source:  University of Sydney media release

Getting your head around dog genetics

Another public release of research this week.  This one from the Genetics Society of America about an article entitled ‘The Genetics of Canine Skull Shape Variation.’  Published in the February issue of Genetics, researchers review progress in defining genes and pathways that determine dog skull shape and development.

The researchers believe that the results are useful to humans because of the genetic expression of the features is likely to be similar process in humans as in dogs.

Skull shape is a complex trait, involving multiple genes and their interactions. Thanks to standardized canine breeding, which documents more than 400 breeds worldwide, and their distinct morphological features, researchers can disentangle traits such as skull shape, which in many breeds is a breed-defining variation.

Researchers are beginning to identify which genes cause a Bulldog or a Pug to have short pushed-in faces, or brachycephaly, and those that cause Salukis or collies to have narrow, elongated snouts, or dolichocephaly.

Source:  Genetics Society of America media release