Trends in popularity of some morphological traits of purebred dogs in Australia.

Background The morphology of dogs can provide information about their predisposition to some disorders. For example, larger breeds are predisposed to hip dysplasia and many neoplastic diseases. Therefore, longitudinal trends in popularity of dog morphology can reveal potential disease pervasiveness in the future. There have been reports on the popularity of particular breeds and behavioural traits but trends in the morphological traits of preferred breeds have not been studied. Methods This study investigated trends in the height, dog size and head shape (cephalic index) of Australian purebred dogs. One hundred eighty-one breeds derived from Australian National Kennel Council (ANKC) registration statistics from 1986 to 2013 were analysed. Weighted regression analyses were conducted to examine trends in the traits by using them as outcome variables, with year as the explanatory variable and numbers of registered dogs as weights. Linear regression investigated dog height and cephalic index (skull width/skull length), and multinomial logistic regression studied dog size. Results The total number of ANKC registration had decreased gradually from 95,792 in 1986 to 66,902 in 2013. Both weighted minimal height (p = 0.014) and weighted maximal height (p < 0.001) decreased significantly over time, and the weighted cephalic index increased significantly (p < 0.001). The odds of registration of medium and small breeds increased by 5.3 % and 4.2 %, respectively, relative to large breeds (p < 0.001) and by 12.1 % and 11.0 %, respectively, relative to giant breeds (p < 0.001) for each 5-year block of time. Conclusions Compared to taller and larger breeds, shorter and smaller breeds have become relatively popular over time. Mean cephalic index has increased, which indicates that Australians have gradually favoured breeds with shorter and wider heads (brachycephalic). These significant trends indicate that the dog morphological traits reported here may potentially influence how people select companion dogs in Australia and provide valuable predictive information on the pervasiveness of diseases in dogs. Keywords: Purebred dogs, Dog popularity, Dog height, Dog size, Cephalic index, Brachycephalic Disease, predisposition, Australia. Plain English Summary Some diseases in dogs are related to certain physical characteristics. For example, larger breeds have a higher risk of getting hip dysplasia and certain neoplastic diseases while breeds with wider and shorter heads, such as Pug and French bulldog, are more likely to experience breathing problems and dystocia. Therefore, if we know the trends in popularity of dogs of a certain morphology, we may be able to predict disease pervasiveness. The study aimed to investigate the trends in the height, dog size and head shape of Australian purebred dogs. The numbers of dogs registered within the 181 breeds in Australian National Kennel Council (ANKC) every year from 1986 to 2013 were obtained and analysed. The total number of ANKC registration had decreased from 95,792 in 1986 to 66,902 in 2013. Compared to taller and larger breeds, shorter and smaller breeds have become relatively popular over time. Also, the data suggest that Australians increasingly favour dogs with shorter and wider heads for whose welfare veterinarians often express concern [1, 2]. The results indicate that dog height, dog size and dog head shape may potentially influence how people select companion dogs in Australia and provide valuable predictive information on trends in disease prevalence, enabling the veterinary profession and industry to prepare for potential future caseloads

Central tarsal bone luxation in three non-racing dogs

SummaryEach of three adult crossbreed dogs suffered a hock injury during regular exercise. A non-weight-bearing lameness and a soft tissue swelling around the tarsus were present in all of them. Additionally dog # 1 on palpation of the calcaneus region exhibited crepitous. Radiographs showed luxation of the central tarsal bone in all three of the animals. Dog # 1 also had a fracture of the calcaneus. Surgical treatment was performed on all of the cases, via a medial surgical approach. The luxated bone was repositioned and attached to the adjacent 4th tarsal bone with a 3.5 mm countersunk lag-screw. The fracture of the calcaneus was stabilized with a 2.7 mm five hole AO-plate. Postoperatively the injured limbs were immobilized with a cast for four to six weeks and exercise was restricted. After cast removal, all of the dogs received physiotherapy. All three hocks regained full function and owners reported normal activity.The successful treatment of central tarsal bone luxation in three non-racing dogs is reported.</jats:p

Measurement of the tibial plateau angle in cats with and without cranial cruciate ligament rupture

SummaryThe objective of the present study was to determine the tibial plateau angle (TPA) in cats without stifle pathology and to compare it with cats suffering from an isolated cranial cruciate ligament rupture. Mediolateral radiographs of the stifle were taken and the tibial plateau angle was measured based on the method previously described by Slocum and Devine (1983) for dogs. Three observers with different levels of experience evaluated the radiographs of all of the cats in this study. The mean tibial plateau angle measured by all three observers in the cats with a rupture of the cranial cruciate ligament (CCL) was 3.1° greater than in cats without stifle pathology. Neither gender, age, body weight nor degenerative joint disease had an influence on measurement results. The authors found an inter-observer variability of ± 5.3°. Hence it can be concluded that cats with cranial cruciate ligament rupture have a greater TPA, and this at least lends some credence to the possibility of higher TPA being a predis-posing factor for cruciate injury in this species.</jats:p

Traumatic avulsion fracture of the lesser trochanter in a dog

SummaryA 15-month-old 25 kg female spayed American Staffordshire Terrier was examined to determine the cause of a six month period of lameness of the left pelvic limb. Signs of severe pain were evident on hyperextension and simultaneous internal rotation or abduction of the left hip joint; crepitus or instabiltiy was not detected. The diagnosis of avulsion fracture of the lesser trochanter was based on radiographs, computed tomography (CT) and magnetic resonance imaging (MRI), supported by initial findings such as lameness and hip joint pain in extension. The dog was treated with strict confinement for eight weeks followed by a gradual increase in activity; non-steroidal anti-inflammatory drugs were given for one month. Three months later, the dog was clinically sound and unrestricted activity was resumed. Soundness was confirmed on follow-up 18 months after injury. CT and especially MRI were powerful diagnostic tools to identify chronic iliopsoas strains with an avulsion fracture of the lesser trochanter. Complete recovery ensued following conservative treatment only, despite the proximal diplacement of an avulsed segment of the lesser trochanter. Thus, traumatic injury to the iliopsoas muscle and to the lesser trochanter should be included as differential diagnosis in cases of hind leg lameness.</jats:p