pug

 

Appearance matters. But what are the costs? The United Kingdom pedigree dog industry has been facing criticism in recent years due to certain aspects of dog conformation, specified in the UK Kennel Club breeds standards, that are having a detrimental effect on dog welfare (Asher et al. 2009). Conformation of breed associated defects were recognised as early as 1868 by Charles Darwin, who hypothesized the muscular defects in Scottish Deerhounds were related to their great size. The domestic dog (Canus familiaris) is the most morphologically diverse mammalian species (vilo et al. 1999). There are currently more than 350 breeds recognised by the Federation Cynologique Internationale (FCI). This large number implies breeding in many small populations, where each breed comprises of a relatively closed genetic pool (Parker et al. 2004). Artificial selection for specific characteristics and behaviours has led to both diversity between species and reduced genetic variation within breeds. In addition, many breeds originate from a small number of founders and have experienced population bottlenecks and popular sire effects, resulting in effective population sizes far smaller than census population sizes (McGreevy et al. 1999; Calboli et al. 2009 and Karlsson et al. 2008). These factors have led to the unique genetic structure of the dog.

But how did this happen? When man first domesticated animals he discovered that he could improve their utility by arranging matings between superior animals (this is not just seen in dogs but also cattle, chickens and horses). This selective breeding was unnatural in a strictly Darwinian sense: the ‘superior’ offspring may not have been fitted for survival in the wild. However, selective breeding under domestication did create animals that were functional in terms of human needs, and usually better adapted to the domestic environment. Thus breeding was born. Those humans fortunate enough not to have to work all day for their survival were able to turn their thoughts to ways of improving the quality of their leisure time. This approach to leisure was seen particularly on the estates of English landowners, individuals who would produce elaborate rituals to pass their time. These rituals included field sports such as hunting and shooting, which required the selective breeding of some animals, especially dogs, to make the killing, of example game birds and foxes, more entertaining. Other dogs were bred to be pretty and pampered and small enough to be carried as fashion accessories (Webster 2005). The strong standard Poodle was shrunk to the dimensions of a toy. The Pug, Pekingese and Chihuahua were not only shrunk but also reshaped to produce big eyes that stare straight into your face like a human baby.

The scary thing here is society and the veterinary profession have become ‘desensitized’ to the welfare issues to such an extent that the production of anatomically deformed dogs is neither shocking nor considered abnormal (Rooney 2009). Rowena Packer and her colleagues (2012) looked at the problems arising in brachycephalic dog (foreshortened muzzle e.g. Bulldogs,) who have a major risk for brachycephalic obstructive airway syndrome (BOAS). Clinical signs include respiratory distress, exercise intolerance, upper respiratory noise and collapse. These signs were seen as ‘normal,’ with over half (58%) of owners with affected dogs reporting that their dog did NOT have a breathing problem. This view will have to change.

Short muzzles are not the only problem. An article by Hodgman (1963) summarised the results of a survey of inherited disorders reported by 104 veterinary practices over a 6-month period. The survey was conducted at the request of (and financed by) the Kennel Club. Five disorders were classified as paramount importance: 1- hip dysplasia, 2- patellar luxation, 3- entropin, 4- ‘retinal atrophy’, and 5- ‘elongated soft palate’. A further eight disorders were placed in the second tier of importance: abnormal temperament, skin fold dermatitis, uterine inertia, elbow dysplasia, lens luxation, ectropion, trichiasis and deafness. At least 10 of these are associated with conformation in some way.

The main problem is the breed standards. The breed standards for eyes in the Chow is ‘the smaller the better’, stifles for German Shepherds is ‘well turned’, and skulls for Pugs is ‘the larger the better’ (Nicholas et al. 2008).

Head, skull, eyes and ears
Many conditions have been connected to the brachycephalic head shape, including static nares, an elongated soft palate and hypoplastic trachea. BAOS is a combination of these conditions with a varying range of severity. Breeds prone to this condition include Bulldogs and Pugs (Lerinson et al. 1997). The large head to pelvis ratio (found in certain brachycephalic breeds) has been linked to dystocia (obstructed labour) (Tillyet al. 2004), as there is an extreme in size (Bergstrom et al. 2006). Dogs with this problem are unable to give birth naturally and are subjected to Caesarean section.

Reduced cranial cavity size is associated with the potentially severe neurological conditions of cranioschisis, hydrocephalus and syringomyelia (SM). This last condition is most commonly associated with Cavalier King Charles Spaniel. It is caused by a malformation of the skull, known as chiari-like malformation (CM), and is supposedly related to skull conformations that steep caudally. CM/SM in Spaniels is commonly associated with pain, especially in the cervical region, and with neurological dysfunction, e.g. scoliosis, limb paresis and ataxia (Rusbridge et al., 2000 and Rusbridge et al., 2006). Affected dogs might be hypersensitive to touch and often scratch an area on the shoulder, ear, neck or sternum, commonly only on one side of the body without making skin contact, so called phantom scratching (Rusbridge et al., 2006). Some dogs perform facial or head rubbing or spontaneous vocalisations. If you watched the BBC documentary “Pedegree dogs exposed,” you would have witnessed a scene which was very difficult to watch of a dog inflicted with this condition. An estimated 95% of Cavalier King Charles Spaniels are affected by Chiari-like malformation and around 70% develop syringomyelia (Dewey and Rusbridge, 2008 and Parker et al., 2011).

Dogs with protruding or sunken eyes are prone to ulceration or irritation of the eye, including ulceration keratitis, keratitis sicca and keratropathy syndrome. Such conditions are of concern, despite their relatively low severity, because of their high incidence in certain breeds. For instance, of those screened by the American Canine Eye Registry Foundation (2007), nearly 8% of Shar-Peis were found to have keratitis and 17% of Pugs had keratopathy syndrome (Asher et al. 2009).

Otitis is frequently recurrent, often chronic in nature, can be very painful (see, for example, Stern-
Bertholtz et al., 2003), and can result in conductive deafness and aural tumours (Fan et al. 2004, Kahn et al. 2005). Six of the top 50 breeds have a reported predisposition to otitis. Otitis externa has been linked with breed characteristics that predispose to skin infections and breeds with pendulous ears, excessive hair in and around the ear (Hayes Jr et al., 1987) and high production of cerumen, typically long-coated breeds (Strain, 1996).

Size, body, forequarters, hindquarters and tails
Large breeds may be predisposed to a number of disorders as a consequence of either their body size or their fast rate of growth. Studies have demonstrated a high prevalence of hip and elbow dysplasias in many large and giant breeds (Stuaros et al. 2005, Genevais et al. 2008). With such polygenic disorders, environmental factors are important, for example, appropriate diet and exercise have been shown to reduce the prevalence and severity and delay the onset of hip problems (Saliander et al. 2006). Conditions associated with small body size are odontoid process dysplasia, shoulder dysplasia, patellar luxation. Patellar luxation, which can cause lameness, reportedly primarily affects breeds from the terrier, toy and utility groups (Asher et al. 2009). Cervical vertebral instability and invertebral disc extrusion (IVDE) are conditions that are both severe and have high prevalence in particular breeds. Most disc extrusions are reported in chondodystropic breeds (e.g. Dachshunds, Basset hounds and Pekingese), where selection for “long and low” morphologies is linked with invertebral discs abnormalities that predispose dogs to IVDE. IVDE can be associated with pain, sensory and motor deficits that can significantly compromise quality of life. In severe cases, this may result in permanent loss of function, with owners choosing to euthanize their dogs or nursing them long-term as paraplegics, in some cases using carts for mobility.

Skin conditions
Many disorders relate to wrinkled skin or excessive skin folds. Dermatitis and pyoderma may not be severe conditions, but they are often recurrent or chronic in nature (Hill et al., 2007). Although a recent estimate could not be sourced, in 1963 skin-fold dermatitis had a high reported prevalence in Bulldogs (17% of 162 of this breed sampled; Hodgman, 1963), Cocker Spaniels (7% of 318 sampled; Hodgman, 1963) and English Springer Spaniels (17% of 24 sampled; Hodgman, 1963). Skin folds may be stipulated in breed standards directly or arise indirectly from the requirement for a brachycephalic skull shape, or cork-screw tails. The Shar-Pei, a breed with many skin folds, presents numerous skin complaints, including cutaneous mucinosis. It is proposed that selection for thickened wrinkled skin may have resulted in this condition since a large amount of dermal mucin is a cause of both cutaneous mucinosis and the thickened and wrinkled skin of the Shar-Pei (Welle et al. 1999).

Entropion and ectropion are conditions of high prevalence in the Shar-Pei, Bulldog and Pug. In giant breeds, entropion and ectropion can co-occur such that the central lower lid is ectropic while at the corners the lid is entropic (producing diamond-shaped eyes) (Asher et al. 2009). Conformational features that can affect the normal eyelid structure include a large distance between upper and lower lids, a small or recessed globe, a visible third eyelid or a drooping lower eyelid (van der Woerdt, 2004). Two related conditions are trichiasis, which is found in breeds with nasal folds or droopy eyelids (Tilley and Smith, 2004) and eversion of nictitating membrane, which is found in larger breeds with facial folds and a distinctive stop (Martin and Gelatt, 2003).

Conclusion
It does seem that the kennel club is towards making a change however small it may be, but it has become increasingly clear that there are issues that need to be addressed now and with some urgency. The stated primary objective of the kennel club is ‘to promote in every way, the general improvement of dogs’ and of course many of its members and governance personnel are pedigree dog breeders. This is where the problem really lies. Many breeders, buyers and fanciers, as well as those who are involved in judging, promote breeds and their ‘established’ characteristics and don’t want to change as they don’t see how there is need for a change. The road to a better future for pedigree breeds is going to be more of an uphill trek than a walk in the park.

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