The study was carried out at the Hidango Experimental Substation (INlA, coastal dryland, VI Region), during 1979 and 1980. A complete randomized design, with a factorial arrangement, was used. Main objetives were to evaluate the effects of stocking rate and supplementation with urea blocks on liveweight. Stocking rates were 6 and 12 and 12, 18, and 24 ewe lambs/ha, in 1979 and 1980, respectively. Both trials started early in February and lasted 70 days. Initial dry matter availability (kg/ha) were 7,817 (1979) and 8,517 (1980). Botanical composition were: hardinggrass (Phalaris tuberosa syn. aquatica) 5.5; subclover (Trifolium subterraneum) 2.2; wheat straw, 67.7; and other grasses, 24.6%, in 1979. In 1980, the proportions of hardinggrass and subclover were higher: 24.8 and 4.8%, respectively. Average dayly intakes/head were 18.5 and 28.5 9 of urea blocks and 2.15 and 1.47 It of water, for 1970 a nd 1980, respectively. It was postu lated that stocking rates were low to detect the effect of the urea blocks. AII treatments (no statistical differences, P > 0.05) showed an initial in crease in L.W., followed by a maintenance period, and ending in L.W. loss. There was a higher increase in individual L.W. on the stubbles than on the native pasture, but final L.W. were similar. Average gains/ha were much higher on the stubbles than on the natural pasture (54.3 vs 6.0 kg). |
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