Determining thermal stress during the transport of mammals
Date
2006-11-01T11:42:45Z
Authors
Wimberger, Kirsten
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Abstract
The high morbidity and mortality of wild mammals and livestock during capture
and transport is generally ascribed to thermal stress. Consequently, capture
operators can benefit from improved methods that may reduce thermal stress. The
aim of my study was to develop a practical method of measuring the body temperature of mammals during capture and transport
operations. Firstly, I determined whether intermittent temperature recordings, which allow for minuteby- minute monitoring of an animal’s temperature, could accurately reflect continuous measures of an animal’s rectal temperature. Intermittent temperatures were measured via telemetry while continuous and off-line recordings were measured with data loggers. Secondly, I compared rectal and abdominal temperatures to determine if rectal temperature can provide a practical, noninvasive method of estimating core body temperature. Additionally, I measured
body temperature and environmental conditions throughout transportation and
compared pre- and post-transport levels of faecal cortisol, and blood cortisol,
haematocrit and catecholamines. Measuring rectal temperatures seems to be the
only feasible, non-invasive technique to obtain temperature during transport
operations. However, rectal temperature records required about 30 minutes to
stabilise after inserting a thermometric device. After rectal temperature stabilised,
generally the difference between abdominal and rectal temperatures varied greatly
for individual animals, while the average differences in temperatures between the
body sites were not significant for all, except one, species. I have also shown that
telemeters and data loggers can be used interchangeably to measure the body
temperature of animals. The differences between temperatures measured by the
devices were not significant, except for substantial differences shown in two
animals. The addition of earphones and a large aerial inside the vehicle improved
the telemetry results, by limiting the extraneous noise of the capture and transport environment. These conditions probably caused the anomalous readings in the two animals. General thermal responses to stress are that animals showed a peak
in temperature due to capture and a decrease in temperature during transport.
Therefore, capture-related stress and the likelihood of animals dying during
capture could be minimised by ensuring that the animals are not chased longer
than a set cut-off time. Further, globe temperature should be monitored to ensure
that animals are not captured in high thermal conditions. In contradiction with the current guidelines regarding the appropriate time of day for capture, I recommend that animals should not be caught at the end of the day, as my results show that this is when their body temperatures are the highest. Body temperatures during
transport and differences in faeces cortisol before and after transport seem to
indicate that animals adapt to repeated stress events.
Description
Student Number: 0218322F
Master of Science
School of Physiology
Keywords
Angora goats, Capture and transport, Mortality wild mammals, Thermal stress, Body temperature, Intermittent temperature, Telemetry, Data loggers, Pre- and post-transport levels, Catecholamines