Canine Seminar Notes
Canine Seminar: Breed Differences in Dogs
Kemp and Carrier Paper: Bones in Fighting vs. Running Dogs
Introduction
The seminar focuses on a paper by Kemp and Carrier investigating breed differences in dogs, specifically comparing those bred for fighting and running.
The paper reference is from the Journal of Experimental Biology.
Key Question 1: Rapid and Economical Terrestrial Locomotion
Rapid and economical terrestrial locomotion relies on the ability to store and recover energy.
Key Question 2: Specialization for Fighting
Specialization for fighting is associated with stout bones that transfer forces over a large range of motion and a high resistance to fracture.
Key Question 3: Deer Antler vs. Calf Bone
The key difference lies in stiffness. Deer antlers are stiffer.
Key Question 4: Bone Loading During Fighting
Fighting loads limb bones in various directions, unlike the consistent vertical loading during high-speed running. This is due to potentially different forces during fighting action.
Key Question 5: Hypothesis About Limbs of Fighting Dogs
The authors hypothesized that the limbs of dogs bred for fighting might require bones that can absorb more energy, a different stiffness requirement compared to running dogs.
Key Question 6: Functional Adaptation
The authors suggested that a stout bone with a larger cross-sectional area could transfer forces over a larger range of motion, beneficial for fighting performance.
High resistance to fracture is seen as a good attribute for bones in fighting animals to withstand various forces.
Key Question 7: Unexpected Measured Variables
No significant differences were found between breeds in maximum stress and maximum resistive force, which was unexpected.
Key Question 8: Skeletal Area Associated with Injuries in Greyhounds
The feet were identified as a skeletal area associated with injuries in greyhounds.
This area is likely not loaded differently between greyhounds and pit bulls, so it is probably doesn't relate to findings of the study in terms of bone differences.
Key Question 9: Most Dramatic Differences
The two most dramatic differences observed were:
Higher elastic moduli of greyhound bones.
Higher work to fracture of pit bull bones, requiring more energy to fracture, potentially beneficial for fighting dogs.
Additional Papers for Revision:
Overview
Three studies are highlighted for additional revision:
Kemp et al. paper on bones.
Passy and Carrier paper on limb musculature (already discussed).
Webster et al. paper on spinal musculature (force generation through apaxial muscles in greyhounds).
Specimen Overlap
The Kemp et al. and Passy & Carrier papers used the same specimens, allowing for comparison of bone and muscle characteristics in the same animals.
Rationale for Separate Papers
Separating bone and muscle aspects into different papers allows for a more thorough examination of each.
Revision Task Suggestion
Summarize the findings from all three papers to understand the differences between fighting and working dogs.
Create a table summarizing the findings of these studies, which can be extended with more literature to build a comprehensive overview of breed differences in dogs.
General Observations
Dogs have been bred for diverse purposes, with running and fighting representing extreme examples.
Breeding dictates bone structure and, to some extent, muscle structure.
Bone and muscle composition is generally conserved among vertebrates and mammals, but differences emerge at a detailed level, especially in dogs.
Differences persist even after normalizing for body weight, highlighting a limitation of kinetic and kinematic analysis.
Additional Reading
Tracy Crook study on pelvic limb muscles in horses, focusing on acceleration and endurance.
Breed Differences
The studies frequently compare extreme breeds, like brachycephalic vs. dolichocephalic dogs.
Diversity in Horses
Similar studies can be conducted for horses, comparing kinematic variables among breeds like Arabians and Thoroughbreds.
Kemp and Carrier Paper: Bones in Fighting vs. Running Dogs
Introduction
The seminar examines a paper by Kemp and Carrier that explores breed differences in dogs, specifically comparing breeds selected for fighting versus those selected for running. This comparison aims to highlight how artificial selection for different tasks affects skeletal and muscular adaptations.
The cited paper is published in the Journal of Experimental Biology, a leading journal in comparative physiology and biomechanics. Its rigorous standards ensure the findings are robust and contribute meaningfully to the field.
Key Question 1: Rapid and Economical Terrestrial Locomotion
Rapid and economical terrestrial locomotion depends on the organism's capability to efficiently store and recover energy during movement. This involves elastic structures like tendons and bones that deform and recoil, reducing the metabolic cost of locomotion.
Key Question 2: Specialization for Fighting
Specialization for fighting is characterized by the development of stout bones that can effectively transfer forces across a wide range of motion, coupled with a high resistance to fracture. These adaptations enable fighters to withstand and deliver powerful blows without sustaining significant injury.
Key Question 3: Deer Antler vs. Calf Bone
The primary difference between deer antlers and calf bones lies in their elastic modulus, or stiffness. Deer antlers are significantly stiffer, making them suitable for high-impact collisions during fights for dominance.
Key Question 4: Bone Loading During Fighting
During fighting, limb bones experience loading in multiple directions, a stark contrast to the predominantly vertical loading seen in high-speed running. This multidirectional loading arises from the variable and unpredictable forces exerted during fighting.
Key Question 5: Hypothesis About Limbs of Fighting Dogs
The researchers proposed that fighting dogs might possess limbs with bones capable of absorbing more energy compared to running dogs, implying variations in stiffness requirements dictated by their respective activities.
Key Question 6: Functional Adaptation
The authors posited that a stout bone, marked by a large cross-sectional area, could facilitate force transmission across a broader range of motion, which is advantageous in fighting. Furthermore, high fracture resistance is crucial for fighting animals to endure diverse forces.
Key Question 7: Unexpected Measured Variables
Contrary to expectations, no significant differences were observed in maximum stress and maximum resistive force between the breeds. This suggests that while bone structure may differ, the ultimate strength might be similar.
Key Question 8: Skeletal Area Associated with Injuries in Greyhounds
The feet were identified as a skeletal region prone to injuries in greyhounds. Since loading in this area probably doesn't differ significantly between greyhounds and pit bulls, its relevance to the study's bone difference findings is limited.
Key Question 9: Most Dramatic Differences
The most pronounced differences were:
Greyhound bones exhibited higher elastic moduli.
Pit bull bones displayed higher work to fracture, indicating they require more energy to break—likely advantageous in fighting scenarios.
Additional Papers for Revision:
Overview
Three main studies are considered:
The Kemp et al. paper focusing on bone characteristics.
The Passy and Carrier paper exploring limb musculature (already discussed).
The Webster et al. paper investigating spinal musculature and force generation via apaxial muscles in greyhounds.
Specimen Overlap
Both the Kemp et al. and Passy & Carrier papers utilized the same specimens, facilitating comparisons between bone and muscle traits within the same subjects.
Rationale for Separate Papers
Dissecting bone and muscle characteristics into separate studies led to a more exhaustive analysis of each component.
Revision Task Suggestion
Conduct a synthesis of findings from all three papers to elucidate the disparities between fighting and working dogs.
Develop a table summarizing the key findings from these studies. This table can be expanded with additional literature to offer a comprehensive overview of canine breed differences.
General Observations
Selective breeding has tailored dogs for various roles, positioning running and fighting as extreme examples.
Breeding practices influence bone structure and, to some extent, muscle structure.
Bone and muscle composition tend to be conserved across vertebrates and mammals, yet notable differences emerge at a detailed level, especially in dogs.
Even after normalizing for body weight, differences persist, highlighting a limitation of relying solely on kinetic and kinematic analyses.
Additional Reading
Consider the Tracy Crook study on pelvic limb muscles in horses, which examines acceleration and endurance capabilities.
Breed Differences
The included studies generally contrast extreme breeds, such as brachycephalic versus dolichocephalic dogs, to accentuate differences.
Diversity in Horses
Analogous studies can be performed on horses, comparing kinematic variables across breeds like Arabians and Thoroughbreds to understand functional adaptations.