Comparative characteristics of the exterior of dogs of northern sled breeds

Purpose: Comparative characteristics of the exterior of dogs of northern sled breeds.Materials and methods. The object of the study was the dogs of the Chukchi sled dog breed and the Siberian husky used in the LLC "Scythians-tour" of the Republic of Karelia. The method of taking body measurements from dogs and calculating body composition indices was used. Body measurements were carried out in 14 males and 8 females of the Chukchi sled dog and 17 males and 7 females of the Siberian husky. From the measurements, the height at the withers, the oblique length of the trunk, the chest circumference, the length of the forelimb, the circumference of the pastern, the length of the muzzle, the length of the head were taken into account. To take measurements, a measuring stick, a compass and a measuring tape were used. Based on the measurements, the physique indices are calculated. The degree of differences was assessed based on the results of biometric processing of indicators using the Excel program.Results. It was established that the males of the Chukotka Sled Dog and Siberian Husky breed were significantly superior to bitches in almost all body measurements, i.e. they were significantly larger than them. The males of the Chukchi sled dog exceeded the Siberian huskies by 6 cm in the oblique length of the trunk, by 2.4 cm in the length of the head. The differences between the bitches of the Chukchi sled and the Siberian Husky appeared only in the chest circumference and the length of the muzzle. The bitches of the Chukchi sled were more downed and massive than the males. In dogs of the Siberian Husky breed, there were no significant differences between males and bitches in all body indices. The males of the Siberian Husky breed were more downed and massive than the males of the Chukchi sled dog. Bitches of both breeds were developed in the same way.Conclusion. Sexual dimorphism in the exterior was manifested in dogs of the Chukchi Sled dog breed. Breed and sex differences of dogs in size, appearance and physique should be taken into account when forming sleds.

Description of breed ancestry and genetic health traits in arctic sled dog breeds

Background This study describes the presence and frequency of health traits among three populations of dogs traditionally used for sledding and explores their ancestry and breed composition as provided by the commercially available Embark dog DNA test. The three populations include the purebred Siberian Husky and the admixed populations of Alaskan sled dogs and Polar Huskies. While the Siberian Husky represents a well-established breed with extensive historical and health data, the Alaskan sled dog is less studied but has been the subject of nutritional, physiological, and genetic studies related to ancestry and performance. In contrast, the Polar Husky is a relatively obscure and rare group of dogs used for arctic exploration with very little-known information. The three populations were compared using Embark results, providing new insight into the health traits circulating within the populations and the potential ancestral linkage of the health traits between the sledding populations. Embark results are based upon 228,588 single-nucleotide polymorphisms (SNPs) spanning the canine genome, characterized using a custom-designed Illumina beadchip array. Results Specifically, breed composition was summarized for the two admixed populations with most of the dogs being predominantly categorized as Alaskan husky- type dog or “Supermutt”. Mitochondrial and Y chromosome haplogroups and haplotypes were found with Alaskan sled dogs carrying most of the haplogroups and types found in Siberian and Polar Huskies. Genomic principal component analysis reflected population structure corresponding to breed and substructure within the Alaskan sled dogs related to sprint or distance competition. Genetic markers associated with Alanine Aminotransferase activity, Alaskan Husky Encephalopathy, dilated cardiomyopathy, Collie eye anomaly, degenerative myelopathy, ichthyosis, and factor VII deficiency were identified in the populations of sledding breeds. Conclusion These results provide a preliminary description of genetic characteristics found in sledding breeds, improving the understanding and care of working sled dogs.

Glucocentric Metabolism in Ultra-Endurance Sled Dogs

The total energy expenditure of a racing sled dog can exceed 500 kcal/kg bodyweight during typical events spanning a week or more. Based on early research, as well as practical considerations, modern commercial diets are formulated to meet these energy requirements using fat and protein. However, more recent research provides a clear picture of a canine athlete with glucocentric metabolism, including many conditioning-induced adaptations oriented towards sustaining submaximal exercise with glucose as the primary metabolic fuel despite the consumption of fat as the primary dietary energy source. The specific strategies used by racing sled dogs to maintain a robust supply of glucose during exercise, as well as the possible role of fat in facilitating that metabolic priority, is the subject of ongoing research.

Emerging risk of Dirofilaria spp. infection in Northeastern Europe: high prevalence of Dirofilaria repens in sled dog kennels from the Baltic countries

Dirofilariasis is a fast-spreading disease of dogs and humans in Europe. We investigated whether Dirofilaria spp. have spread northwards in Europe, invading the Baltic countries. Altogether, 424 blood samples were collected from eight countries in the period 2017–2019, including 227 samples from sled dogs and 197 samples from other dogs. PCR amplification and sequencing were conducted employing three genetic markers (mitochondrial [mt] 12S rDNA, mt cytochrome c oxidase subunit I [COI] gene and mt dehydrogenase subunit I [NAD1] gene). The SNAP test (IDEXX) for detection of D. immitis infections was also implemented. The DNA of D. repens was detected in 59 of 424 dogs (prevalence 13.9%). D. repens was found in sled dogs from Lithuania, Latvia, Poland and Belarus. Only one dog from Estonia was infected, apparently an imported case. The highest prevalence was recorded in Lithuania (38%). Among pet dogs from the Ukraine, six dogs tested positive (3.8%). Our study has revealed a high prevalence of D. repens infections in Lithuania and Latvia, but no evidence for spread of the heartworm D. immitis. We conclude that sled dog kennels constitute hot spots for D. repens transmission.

Arctic-adapted dogs emerged at the Pleistocene–Holocene transition

Although sled dogs are one of the most specialized groups of dogs, their origin and evolution has received much less attention than many other dog groups. We applied a genomic approach to investigate their spatiotemporal emergence by sequencing the genomes of 10 modern Greenland sled dogs, an ~9500-year-old Siberian dog associated with archaeological evidence for sled technology, and an ~33,000-year-old Siberian wolf. We found noteworthy genetic similarity between the ancient dog and modern sled dogs. We detected gene flow from Pleistocene Siberian wolves, but not modern American wolves, to present-day sled dogs. The results indicate that the major ancestry of modern sled dogs traces back to Siberia, where sled dog–specific haplotypes of genes that potentially relate to Arctic adaptation were established by 9500 years ago.

Pre- and Post-Race Intestinal Microbiota in Long-Distance Sled Dogs and Associations with Performance

Although our understanding of the role of the gut microbiota in different diseases is improving, our knowledge regarding how the gut microbiota affects functioning in healthy individuals is still limited. Here, we hypothesize that the gut microbiota could be associated with sled dog endurance-race performance. We investigated the gut microbiota in 166 fecal samples from 96 Alaskan Huskies, representing 16 teams participating in the 2016 Femund Race (400 km) in Norway, relating the microbiota composition to performance and metadata derived from questionnaires. For 16S rRNA gene sequencing-derived compositional data, we found a strong negative association between Enterobacteriaceae (dysbiosis-associated) and Clostridium hiranonis (normobiosis-associated). The teams with the best performances showed both the lowest levels of dysbiosis-associated bacteria prior to the race and the lowest change (decrease) in these bacteria after the race. Taken together, our results support the hypothesis that normobiosis-associated bacteria are involved in resilience mechanisms, potentially preventing growth of Enterobacteriaceae during the race.