EQUINE RESEARCH CENTRE’S FIRST PROJECT STUDIES WASTAGE IN THOROUGHBRED HORSES IN GAUTENG
This study took place over a few years, with the paper being published in 1996. Here is an edit of this paper.
An epizootical study of wastage in Thoroughbred racehorses in Gauteng, South Africa
Wastage is the term used to describe the loss of racehorses from conception to adulthood due to death or injuries, where they never reach the racetrack, or the days lost by racehorses due to not training or being withdrawn from a race. This study was conducted to investigate wastage in Thoroughbred horses used for flat racing in Gauteng, South Africa.
Similar studies have been performed in Newmarket, United Kingdom, at Canterbury Downs in Minnesota and of the Canadian Standardbreds. However, since no data on the incidence of wastage in South Africa were available, this study was implemented. Data from 6 racing stables were recorded from March 1993 to February 1994. Each trainer was required to complete a daily training record of the horses in his stable. The questionnaire included reasons why a horse failed to train on a specific day, or was withdrawn from a race. During the year 8.1% of the total potential training days were lost by horses in the stables investigated. Of these 72.1% were due to lameness, 8.6% to respiratory problems, and 19.3% to other causes (bad weather, vaccinations, wounds etc). The horses with respiratory conditions showed one or more of the following symptoms : coughing, nasal discharge, pharyngitis, epistaxis and upper respiratory noises. The data on the causes of lameness were not included in this study owing to the absence of veterinary confirmation, or that more than one cause of lameness was cited by the trainer in an extended convalescence period. The lost training days for the individual trainers ranged from 5.4 to 12.6%.
The effect of season (summer, autumn, winter and spring) on the incidence of lameness and respiratory tract conditions were also measured, as was the effect of age of the horse. The training days lost due to lameness were considerably higher in autumn and significantly lower in spring. The number of respiratory problems was significantly higher in winter. Lameness occurred more in 3-year olds than 2-year olds, while respiratory problems were significantly higher than expected in 3- and 4-year olds.
The study was continued in 1994/95, but the numbers of days and horses were not added to the first year’s results due to marked decrease in the return of questionnaires from the trainers. However, it was evident that the percentage of training days lost was similar to the previous year, as were the percentages of loss due to lameness (66.9%) and respiratory problems (8.4%) similar to the previous year.
The increased incidence of lameness in autumn months may have been due to relatively low rainfall and temperature, resulting in harder tracks, but there would have to be other causes, as winter also experiences low rainfall, and there was no significant increase in lameness during this season.
The study showed a relatively low level of wastage due to respiratory problems (8.6%) compared with previous studies by Rossdale et al (20.5%) and Herzog & Lindner (22.6%). This could be attributed to the fact that there are lower temperatures prevailing for a longer period of time in the United Kingdom.
The increase of the number of training days lost due to respiratory problems in winter may be caused the lower temperatures or poor stable management. During winter it is common practice to close stables up with the intention of keeping the horses warm, thus affecting ventilation and increasing residual dust.
There could be several causes for the difference in training days lost due to lameness between 2- and 3- year olds, such as that 2- year olds may only start racing from 1 October in the year they turn 2. Trainers may also tend to spare the 2-year olds and push the 3-year olds harder to perform.
The effect of age on the increased incidence of respiratory problems (3- and 4-year olds), may be explained by the fact that 3- and 4-year olds may be travelling more and therefore be more exposed to respiratory pathogens than the other age groups. These 3- and 4-year old horses may also have been stabled with inadequate ventilation, leading to chronic respiratory disease, for relatively longer periods than the 2-year olds.
From the data collected it was concluded that lameness and respiratory conditions were the two most important causes of wastage in Thoroughbred racehorses in Gauteng in 1993/94. Continued research should be conducted to increase our knowledge of the reasons for the occurrence of these conditions in order to prevent them and minimise their effect on Thoroughbred racing in South Africa.
Publication : Journal South African Veterinary Association (1997) 68(4): 125-129
Research Team :
Dept of Surgery, Faculty of Veterinary Science, University of Pretoria : A Olivier
Equine Research Centre, Faculty of Veterinary Science, University of Pretoria : JP Nurton, AJ Guthrie
SURVEY OF SELECTED DESIGN AND VENTILATION CHARACTERISTICS OF STABLES IN THE PRETORIA, WITWATERSRAND AND VERENIGING AREA OF SOUTH AFRICA
The cost of building stables is a major capital expense that faces horse owners today, with the cost of building traditional structures being so prohibitive as to have people resorting to using non-traditional materials and designs. There has also been a trend towards housing several horses in large barn-type buildings, which has made it more difficult to provide a suitable environment for the horses in the buildings, and thus to effectively control disease.
If only considered from the point of view of the horse’s health, it would be optimal to leave the animals outside year-round. By providing adequate food and allowing the horse to acclimatise to normal seasonal changes, horses would develop a good coat and there would be no further need for protection from the elements than that provided by windbreaks and trees. However, today there are many factors that require that horses be stabled. Therefore the first essential of stabling is to give the horses as healthy an environment inside the stables as they would have outside, and adequate protection from the elements. Stables should also provide a good environment and facilities for the people involved with the horses.
The essentials that should be provided by stables are :
- A reasonably uniform temperature;
- A dry atmosphere with no condensation on the building’s surfaces;
- Good air movement and ventilation without drafts;
- A sound dry floor;
- Good drainage;
- Adequate lighting;
- Good watering and feeding arrangements.
Basic environmental requirements
The main factors that affect the climatic environment of stables are ambient temperature, relative humidity, ventilation rate and air movement. To provide stabled horses with the correct climatic environment and reduce the likelihood of disease it is important to consider the horse’s physiological needs.
- Ambient temperature : Unlike humans, acclimatised horses can easily tolerate a wide range of ambient temperature (0°C - 30°C), provided the atmosphere is not damp and drafts are limited. In reality the air flow and ventilation of stables are seriously restricted in what is usually an unnecessary attempt to keep the horses ‘warm’.
- Relative humidity : The survival of most respiratory viruses and bacteria is greatly enhanced in cold, humid environments. The possibility of developing disease, especially respiratory disease, is much greater in stables that are damp and have condensation on the internal walls. As horses exhale large amounts of moist air, poorly ventilated stables will often have condensation on the walls, roof and windows.
- Stable ventilation : Stable ventilation influences environmental temperature, relative humidity and the concentration of noxious gases, dust and microbes. As horses are expected to perform as athletes, lung health is of primary concern. Stable ventilation should thus be provided to maintain ‘fresh air’ for the horses’ respiratory well-being.
The South African situation
In South Africa, the coldest temperatures experienced in stables during winter are well within the horses’ range of comfortable temperatures. As such one should not be concerned that a well-ventilated stable will be too cold. In summer, on the other hand, the temperatures often exceed the upper limit of the temperature comfort zone for horses, so measures to maximise ventilation to ensure lower indoor temperatures should be adopted. Incorporating optimal ventilation will also help to provide the ‘fresh-air’ that is so vital for the stabled horses’ respiratory health.
The Equine Research Centre (ERC) completed a survey of the ventilation characteristics of more than 4 700 stables in the then PWV area. Ventilation rates were determined under optimal conditions (i.e. all vents and top stable doors open) and under minimal conditions (i.e. all adjustable vents and top stable doors closed). It was noted that even with all vents and top stable doors open, the ventilation rate of only 33% of the stables was above the recommended value of 8 air changes per hour (ach). It was alarming to note that the ventilation of about 25% of the stables was below the minimum required rate of 4 ach. The effect of closing all adjustable vents and the top stable doors resulted in the ventilation rate being below the minimum value (4 ach) in 35% of the stables, with the ventilation rate of above the recommended 8 ach being evident in only 9% of the stables. These results showed that the vast majority of the stables surveyed were sub-optimally ventilated. The results also showed that older stables (pre-1970) were better ventilated than those built more recently.
It was evident that many design features and management practices were aimed at keeping the horses warm, in spite of the mild South African climate. Due to the wide thermal comfort zone of horses, this is usually totally unnecessary, and is further more detrimental to the health of the horses. The practice of closing top stable doors or shutters on barns, should be avoided year-round.
Excellent computer models are now able to predict the impact of stable design will have on the temperature, humidity and ventilation of the stable, and should be adopted when designing stables. They also allow one to investigate how to improve ventilation in existing buildings. The authors of this paper offered their expertise to assist with building or improving current buildings.
Publication : Journal of the South African Veterinary Association
Research Team : Prof A J Guthrie, Mr R J Lund – Equine Research Centre, Faculty of Veterinary Science, University of Pretoria