Energy expenditure of walk in grassland for small ruminants

Energy requirements of grazing animals may dramatically increase over those of confined animals. This increase is due to additional oxidation of metabolic fuel in the tissues. Under some grazing circumstances, the energy cost associated with walking can have an appreciable effect on the energy requirements. Muscle is the primary tissue involved in physical activity. Its physiology and mechanical functions are affected by different factors and can even change along the life of the animal. This affects the efficiency of energy utilization. The usual method of determining the energy cost of locomotion has been the combined use of calorimeters and treadmills but not too much research has been done in this area with small ruminants, particularly goats. Even if the accuracy in the determination of the energy cost of locomotion is a vital point, it is not less important to achieve an equivalent level of accuracy in the methods to be applied to determine the distance travelled. Further investigation is needed to improve existing techniques and develop new ones for application to animals in open range systems in order to accurately assess their energy requirements. This will contribute to significant improvements in models of grazing systems. © 2005 Elsevier B.V. All rights reserved