SAEVA Congress 2018 Proceedings | 12-15 February 2018 | ATKV Goudini Spa
Field Testing for Assessment of Athletic Potential and Impaired Performance
Warwick M . Bayly BVSc , MS , PhD , Dip ACVIM College of Veterinary Medicine , Washington State University , Pullman WA
Since time in memorium , owners , trainers , breeders and others associated with equine competition have been looking for ways to get a jump on the field . With the upsurge in interest in exercise physiology and improvements in technological expertise , some tests previously restricted to use in humans are now adaptable to equine studies . Much of the initial work has been done using treadmills . While they are useful instruments with which to evaluate exercising horses , the need to transport the animals to the site of the treadmill has severely curtailed the extent to which performance profiles in horses can be implemented .
The recent introduction of face masks that can be worn in field conditions by horses under saddle , and utilized for the breath-by-breath recording of inspiratory and expiratory air flows , tidal volumes and breathing rates and the associated calculation of oxygen consumption up to its maximum level ( VO 2 max ), has stimulated renewed interest in the conduct of performance profiles of horses .
As promising as this approach is , some words of caution need to be uttered . Most of the information that exists concerning the physiologic profiles of equine athletes relates to average or less than average performers . There is a dearth of real information from champions . This is not surprising given the sizable economic considerations which are involved when evaluating such animals . Also , interpretations of results gathered in the field will remain equivocal until test conditions can be better standardized and until data from large groups of horses are available for comparison . Nevertheless the development of tests that can be utilized in the field has provided access of large numbers of animals to this sort of testing when compared to those that had previously been able to avail themselves of the opportunity to be evaluated on treadmills .
ENERGY UTILIZATION
All mammals require energy in order to contract their muscles . Basically , energy can be derived from 2 general sources – the aerobic and anaerobic systems . In some species the predominant system varies with activity and its duration . However , horses have an extremely well developed aerobic system ( far better than in all or most other species ) due to the adaptations in the skeletal muscles and the existence of the spleen as a major cardiovascular reserve by virtue of the fact that blood volume and O 2 carrying capacity of the blood can increase by as much as 55 % when the spleen is fully contracted . Consequently , aerobic metabolism is the principal source of energy production in virtually all equine athletic events . In even the briefest high speed competitions it estimated that aerobiosis accounts for about 70 % of the total energy used .
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