Prevalence of heat stress in horses, donkeys and mules working in brick-kilns in India
Heat stress is an abnormal physiological state which occurrs when the body is unable to cool itself and maintain a healthy temperature. Anecdotal reports suggest that equids working in Indian brick kilns often suffer from heat stress, however clinical records are often incomplete. Without an accurate estimate of its frequency it is difficult to design and monitor interventions that address prevention and treatment of heat-stressed animals. This study aimed to estimate the prevalence of heat stress in equids employed in brick-kilns in India and document owner beliefs and practices about its prevention and management.
Between May-June 2015, 339 horse, donkey and mule owners were interviewed and their animals were assessed in Uttar Pradesh-Baghpat, Unnao and MaharashtraLatur- Latur, India. Equids were observed 30 minutes after completing work in the brick-kiln. Behavioural (position of head at or below top-line, increased head movement/ nodding, forward and backward body movement, flaring of nostrils, muscle tremor/shake) and clinical parameters were noted. Animals suffering from heat stress were treated and monitored.
- Of 339 animals examined, 18 (5%) were suffering from heat stress. Compared with a previous study this was a low prevalence. This may be because the study occurred at the end of the brick-kiln season, when working hours are reduced and average environmental temperatures are lower.
- Large numbers of equids were thirsty, likely having a negative effect on their health and welfare.
- Animals in direct sunlight were found to have slightly higher percentage of heat stress than those in the shade.
- Less than half of equid owners used preventive measures to reduce the occurrence of heat stress or from their animals becoming thirsty.
- Monitoring horse, donkey and mule behaviour during work hours may reveal opportunities to introduce simple measures that reduce the risk of animals developing heat stress.
- Evidence based treatments for heat stress can be readily administered by owners. Making them aware of the importance of these in preference to current non-evidence based approaches is vital for effective management.
- Offering drinking water, providing shade, and bathing with water is vital to reduce the risk of heat stress.