COMPARATIVE WATER-CONSUMPTION AND EFFICIENCY IN 3 DIVERGENT SHEEP TYPES

Cumulative feed and water intakes and body weights of 30 growing ewe l ambs of three different breeds were recorded weekly for 34 weeks betwe en October 1990 and June 1991 at the Experimental Farm of the Universi ty of Pretoria. The results were analysed to obtain water efficiencies on both an absolute and metabolic weight gain basis. On an absolute b asis, Mutton Merino sheep consumed 145% and Dorper 109% more water tha n Blackhead Persian sheep. On a metabolic weight gain basis, the corre sponding differences were 92 and 66%, respectively. Mutton Merino and Dorper lambs also consumed 69 and 41% more water per kg feed intake th an the Blackhead Persians, respectively. Weekly water consumption incr eased twice as much per 1-degrees-C increase in ambient temperature in the Dorper and Mutton Merino lambs as in the Blackhead Persians. Thes e results suggest that sheep of the Blackhead Persian, and probably al so other indigenous breeds, balance their water requirements at a more economical level and would be a more appropriate choice than those br eeds currently being managed in sustainable sheep production systems i n areas where water availability is limited.