8.2 Poor athletic performance
There are many causes of poor athletic performance. Many owners expect great results from their horse, particularly if they have made a substantial financial investment, and often animals are presented for examination because they have failed to achieve the owner's hopes. Therefore, one of the first requirements, when examining a horse presented for disappointing performance, is to estabwhether there has been a recent loss of proven form, or whether the animal has never performed as the owners hoped. Only one animal will win a race and the others usually do not do so because they are not good enough on the day! It may be that the horse has not been trained appropriately, or that it has been entered for the wrong event. It may be very difficult to explain to owners that their horses lack ability.
These difficulties have placed a great deal of pressure on veterinarians to come up with a diagnosis in the poor performance case. Fortunately, this pressure has resulted in an improvement in diagnostic ability due to a greater understanding of equine disease and exercise physiology and to the development of new investitechniques. No doubt the availability of these specialist investigative techniques will increase. The more widespread availability of high-speed treadwill undoubtedly improve the proportion of cases in which a definitive diagnosis is reached.
Frequently, the problem in pinpointing the cause of poor athletic performance is that there is not one single condition which is responsible, but that it is due to a combination of minor abnormalities. The investigation of a horse with poor performance therefore requires a thorough examination of all body systems. In a referral centre, a number of different specialists may be involved in the examEven when a problem is identified, other systems should be investigated so that other problems are not missed. One of the difficulties in interpreting statistical analysis performed on case records by specialist centres is that the numbers are biased by the referral case load, the facilities available and the fields of interest of the clinicians involved.
Cardiovascular disease is often suspected as a cause of poor athletic perforin horses. Because so many horses have arrhythmias and murmurs which are physiological it is very important that these are not mistaken for signs of significant heart disease and used to explain poor performance. In the UK, musculo-skeletal disease, upper airway obstruction and lower airway disease are more common causes of poor athletic performance than cardiac disease. These diseases will be discussed briefly so that they can be considered when evaluating animals in which cardiac disease is suspected to be the cause of poor perforMore detailed descriptions are found in articles listed in the reading list.
8.2.1 Musculo-skeletal disease
8.2.2 Upper respiratory disease
8.2.3 Lower respiratory tract disease
8.2.4 Cardiovascular disease