Abstract:
This investigation has been carried out in three nature
reserves in the Transvaal, the Kruger National Park and
in two game reserves in Natal. Specimens for trace
element analysis were collected also from Natal and from
three Lowveld nature reserve complexes.
A study of 104 individuals of nine species of animals after locomotory stress indicates that the primary cause
of mortality after a short (2 km) chase is a profound
acidaemia, with muscle pH significantly lower than that of
central venous blood. There was a s·ignificant correlation
between pH and blood lactate.
Systemic changes include aberrations in the electrocardiogram
configuration associated with hyperkalaemia, depression
of calcium ions, tachycardia (up to 350 beats per
minute), hypotension and a pulmonary arterial hypertension.
High capillary haematocrit together with low P02 , pH and
high PC02 indicated peripheral stasis. A rise in the
haematocrit of central blood after restoration of the
blood pH by infusion of bicarbonate indicated a return of
sequestrated blood to the circulation.
Plasma myoglobin and haemoglobin showed a significant correlation with distance run. There was a significant rise in
blood potassium to near lethal levels.
Reduced kidney function due to vasospasm, relieved by
alpha-blockade with phenoxybenzamine hydrochloride, is
believed to predispose to tubular blockade with blood and
muscle pigments as demonstrated at autopsy.
High levels of GOT, GPT, CPK and LDH were seen in all animals
subjected to locomotory stress (except in trained
animals). There was a significant difference between stress due to transport and exercise stress. Investigation of liver content of trace elements on a seasonal basis revealed a significant correlation between chlorine, cobalt, magnesium, sodium and zinc. Major differences were determined exceeding 200 percent in the seasonal variation of selenium as well as copper, cobalt
and other essential trace elements.
Highly significant differences were apparent in enzyme peaks
between the first and subsequent runs. Differences were
also seen in plasma haemoglobin and myoglobin between animals run for the first time, and after several dummy or
training runs at low speed. It is concluded that preliminary exercising of animals and their familiarisation with capture methods and corrals is the best prophylactic against stress during capture.
