The Indian Journal of Small Ruminants
Year : 2007, Volume : 13, Issue : 1
First page : ( 1) Last page : ( 18)
Print ISSN : 0971-9857.

Energy expenditure of sheep and goats at pasture - A review

Shinde A. K., Karim S. A.

Central Sheep and Wool Research Institute, Avikanagar 304 501, Rajasthan, India.

Received:  22  June,  2007; Revised:  7  July,  2007.

Abstract

Energy expenditure of confined sheep and goats is commonly measured in calorimetric chambers. Such measurements are generally extrapolated for expressing the energy expenditure of animals at pasture. This measurement under or over estimates the values when compared with actual measurements made by indirect calorimetry. Animals at pasture are exposed to wide range of ambient temperature, humidity and solar radiation, pasture availability and walking distance thus energy expenditure of animals are also widely varied under different topographies. The maintenance energy requirement of sheep at pasture is reported to be 25 to 100% greater than for animals in confinement. Maintenance energy requirements ranges from 389- 460 in sheep and 424–522 KJ/kg W^0.75 in goats. Daily energy expenditure of adult sheep is reported to 4.16 at stall and 5.81 MJ/day on pasture during different seasons in tropics. The energy cost of main physical activities (walking and eating) and thermoregulation has been reported in sheep and goats by several authors. Energy expenditure in goats remained minimum up to 38.5°C rectal temperature by efficient evaporative heat loss and above 38.5°C EE increased sizably. Similarly energy cost of walking increased from 3.35 for horizontal movement to 31.7 for ascending and –13.2 Jkg⁻¹BWm⁻¹ for descending movement. Energy cost of eating ranged from 1.55 for concentrate to 9.02Jkg⁻¹BWg⁻¹ for roughage. Various methods for measurement of EE in sheep and goats on pasture have been discussed with their merits and demerits. The effect of various factors affecting EE of animals on pasture in different environment has been elaborated.

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Keywords

Energy Expenditure, Environment, Goats, Pasture, Sheep.

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