Limb development in skeletally-immature large-sized dogs: A radiographic study

Abstract

Despite the extreme morphological variability of the canine species, data on limb development are limited and the time windows for the appearance of the limb ossification centres (OCs) reported in veterinary textbooks, considered universally valid for all dogs, are based on dated studies. The aim of this study was to acquire up-to-date information regarding the arm, forearm and leg bone development in skeletally-immature large-sized dogs from 6 weeks to 16 weeks of age. Nine litters of 5 large-sized breeds (Boxer, German Shepherd, Labrador Retriever, Saarloos Wolfdog, White Swiss Shepherd Dog) were included, for a total of 54 dogs, which were subject to radiographic examination on a bi-weekly basis. The appearance of 18 limb OCs was recorded and 14 radiographic measurements were performed; their relationship with age and body weight was investigated and any breed differences were analysed using different statistical non-parametric tests. The number of OCs present was significantly different at 6 and 8 weeks of age between the investigated breeds. The appearance of the OCs occurred earlier in the Saarloos Wolfdog, while the Labrador Retriever was the later breed. In Boxers and Labrador Retrievers, various OCs showed a delayed appearance compared to the data reported in the literature. The number of OCs was strongly and positively correlated to body weight. Breed differences were also observed in the relative increase of the measured OCs and were not limited to dogs of different morphotypes. Statistically significant differences were most frequently observed between Saarloos Wolfdogs and the other breeds. The OCs that showed a greater variability in their development were the olecranon tuber, the patella and the tibial tuberosity. Their increase was more strongly correlated with the dog’s age and body weight. Our data strongly suggest that differences in limb development exist in dog breeds of similar size and morphotype.

Scientific and technical assistance on welfare aspects related to housing and health of cats and dogs in commercial breeding establishments

“…Canine breeds have, however, highly variable progression of skeletal development due to their morphological variability. A recent study performed by Roccaro et al (2021) demonstrated that even breeds of the same size and morphotype displayed different progressions of the limb ossification centres over time. These authors stated that there is a need for further research on the exact time windows of ossification centres and growth plate closure in the different canine breeds as the majority of the information was mainly obtained from old studies performed on small samples of German Shepherds, Greyhounds and Beagles.…”

Age estimation of puppies based on the radiographically assessed development of ossification centres in the carpal and metacarpal regions

“…37 In small-sized breeds, apart from the small-to mid-sized Beagles, 15,38 only a few studies were performed. 31,32,39,40 In addition, most of the studies included only a small sample, often ranging between 10 and 20 dogs, except the studies of Roccaro et al 33 (54 dogs), Yonamine et al 15 (222 dogs) and Smith 34 (nearly 400 dogs). Furthermore, many of these studies were performed for reasons other than age estimation and only included the timing of the first appearance of OCs or the closure of growth plates, without an attempt to define and follow up intermediate stages in a standardised way.…”

“…In small‐sized breeds, apart from the small‐ to mid‐sized Beagles, 15,38 only a few studies were performed 31,32,39,40 . In addition, most of the studies included only a small sample, often ranging between 10 and 20 dogs, except the studies of Roccaro et al 33 . (54 dogs), Yonamine et al 15 .…”

“…In contrast with tooth development, more resources on radiological bone development are readily available. However, most of the data are collected from medium and large dog breeds only, 15,[23][24][25][26][27][28][29][30][31][32][33] or from unspecified breeds. [34][35][36] Nevertheless, breed (size)-specific growth patterns must be taken into account.…”

Morphometrical and Immunohistochemical Evaluation of Kidney as an Indirect Parameter to Estimate Age in Puppies in Veterinary Forensic Pathology

“…For these reasons, this technique could not be used in animals younger than 18 months old. Another age estimation method used in mammals is the evaluation of the skeletal age, specifically the radiographic appearance and formation of ossification centers in fore- and hind-limbs bones [ 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. Moreover, these methods are affected by environmental factors, such as nutritional, hormonal, and pathological changes [ 14 , 18 , 38 , 39 ].…”