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Heart weight and running ability
1Department of Anatomy, University College, Cork, Ireland.
Insights
Heart weight relative to body and muscle mass decreases with growth and increasing size in horses and dogs. Athletic breeds like Thoroughbreds and Greyhounds show proportionally larger hearts, indicating adaptation for speed.
Area of Science:
- Comparative anatomy
- Animal physiology
- Sports science
Background:
- Heart weight is a key indicator of cardiovascular health and athletic potential.
- Understanding how heart size scales with body mass is crucial in animal physiology.
- Breed-specific adaptations in athletic animals warrant investigation.
Purpose of the Study:
- To compare heart weight with liveweight and total muscle weight in horses and dogs.
- To analyze how these proportions change during growth and across different breeds.
- To investigate if athletic breeds have distinct cardiac mass proportions.
Main Methods:
- Dissection techniques were used to determine heart weight.
- Measurements were taken in adult and growing horses and dogs of various breeds.
- Heart weight was correlated with liveweight and total muscle weight.
Main Results:
- Heart weight as a proportion of liveweight and total muscle weight decreases with increasing body size.
- Thoroughbred horses and Greyhounds exhibit a greater heart weight proportion relative to liveweight compared to less athletic breeds.
- Greyhounds possess a higher heart weight relative to total muscle mass than other dog breeds.
Conclusions:
- Body size and growth significantly influence the relative heart weight in equines and canines.
- Athletic specialization in breeds like Thoroughbreds and Greyhounds is associated with a proportionally larger heart.
- Relative heart mass may be an indicator of high-speed running capacity in dogs and horses.
Abstract:
The weight of the heart as determined by dissection techniques was compared with liveweight and total muscle weight in different types of horses and dogs as adults and during growth. With increasing body size both within and between species, heart weight forms a lesser proportion of liveweight and of total muscle weight. Heart weight forms a greater proportion of liveweight in Thoroughbreds and Greyhounds (breeds noted for high speed running) than in other less fleet members of their species and Greyhounds have greater heart weights relative to total muscle weight than other dogs.