Martin, Donna G. (1993) Work capacity and fatigue in draught ruminant animals. Masters (Research) thesis, James Cook University of North Queensland.

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Abstract

The aim of this study was to define the work capacity of ruminant animals and to investigate the various factors which could limit or enhance this capacity. A series of three experimental studies was conducted comparing work capacity and physiological and metabolic responses to work in untrained and trained animals. The first experiment involved the comparison of four untrained and four trained swamp buffalo which were walked on a treadmill at 0.69 m/sec for a maximum period of three hours, while pulling four different draught loads equivalent to either 0, 5, 8 or 11% of their live weight.

In the second experiment, three Indonesian breeds of cattle (six of each), either untrained or trained, were compared. The breeds (Ongole, Bali and Madura) were worked in pairs, each pair pulling a draught load equivalent to 12% of the combined live weight of the pair, while walking around a dirt track at approximately 0.69 m/sec for a maximum period or three hours.

The third experiment involved the comparison of six untrained and six trained merino wethers which were walked on a treadmill at speeds of either 0.67, 1.04 or 1.38 m/sec for a maximum period of three hours while pulling a draught load equivalent to 11 % of their respective live weight.

In all experiments, changes in body temperature, respiration rate and pulse rate were monitored as well as changes in the concentration of selected blood metabolites in the circulation. The uptake/output of the blood metabolites were also measured in wethers used in the third experiment.

The work capacity of each species was found to increase significantly after only a short period of training; the advantage of training being more clearly demonstrated at higher levels of work. Improvements In the cardiovascular system and the oxidative capacity of these animals were responsible for this enhanced work capacity.

Hyperthermia appeared to be the major factor causing the onset of fatigue In the working ruminants studied. The oxygen saturation of blood was reduced and the likely depletion of the glycogen reserves of the animals in hyperthermia might also have had a role in the onset of fatigue.

The accumulation of lactate in the blood occurred in animals subjected to heavy workloads. This was more noticeable in the untrained animals and in the Bali and Madura breeds than in the Ongole. However, no acidosis occurred but a condition of mild respiratory alkalosis was observed.

In sheep it was found that the hind-limb muscles did not always produce lactate but in fact took up the metabolite, presumably to use as a fuel. It is likely that this would also have occurred in cattle and buffalo.

It was suggested from evidence presented in this study that under normal working conditions, it would be unlikely that the work capacity of draught animals would be limited by lactic acidosis; rather, hyperthermia would most probably be the major problem.

Item ID:	48278
Item Type:	Thesis (Masters (Research))
Keywords:	beasts of burden; buffalo; cattle; cows; draft ruminants; draught animals; draught ruminants; exercise; fatigue; physiology; sheep; wethers; work capacity
Date Deposited:	04 May 2017 04:31
FoR Codes:	07 AGRICULTURAL AND VETERINARY SCIENCES > 0702 Animal Production > 070203 Animal Management @ 50% 07 AGRICULTURAL AND VETERINARY SCIENCES > 0799 Other Agricultural and Veterinary Sciences > 079999 Agricultural and Veterinary Sciences not elsewhere classified @ 50%
SEO Codes:	83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8399 Other Animal Production and Animal Primary Products > 839999 Animal Production and Animal Primary Products not elsewhere classified @ 100%
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