Estimation of the dry- and organic-matter intake of young sheep grazin a dry Mediterranean pasture, and their maintenance requirements

The organic matter intake of two breeds of sheep grazing a dry medic pasture was estimated by five different methods. The methods used were the calibrated weight estimate for measuring available herbage before and after grazing; a total faeces collection and digestibility trial ; a tritium dilution technique ; an established ratio of dry-matter intake to water intake; and an estimation using established energy requirements and the estimated metabolizable energy of the pasture. All methods gave similar estimates. It was concluded that the tritium dilution technique was the most useful method and that the dry-matter intake to water intake ratio was the easiest technique to use. The relative merits of the different methods used are discussed. The maintenance requirement for grazing German Mutton Merino and Awassi sheep was found to be 0–64 MJ ME/day/kg W0–76. When both breeds were caged in an open field the maintenance was 0.37 MJ.