Semiextensive sheep production system on annual range of the subhumid Mediterranean dryland

Julia Avendafto R.1, Carlos Ovalle M.2 y Teresa Aravena A.1

The objective was to get a biological evaluation of the productivity of a sheep raising system with the introduction of technology as range fertilization and barn lambing. This system was evaluated during six growing cycles or seasons grazing a dryland annual range as the principal feeding source except the one supplied in the lambing barn. In two paddocks, one of 23 ha (without fertilizer) and another, annually fertilized (8 to 32; 13 to 44; 7 to 12 kg ha-1 of N, P and K, respectively) of 10 ha, grazed 45 to 51 Suffolk-down ewes with deferred continuous grazing. Results were shown of the seasons that got the highest (sixth season), the lowest (second season), the least deviaton from the mean (first season) and the mean of the six seasons. Weaning or reproductive efficiency rate in the sixth, second and first seasons and the mean of the six seasons were 103.9; 96.0; 111.1 and 94.3%; ewe production (Iiveweight of weaned lamb) was 35.5; 27.9; 37.9 and 31.9 kg, respectively. The liveweight sales and the net liveweight production were 51.1 and 49.9 in the first season; 28.1 and 23.0 in the second season; 34.7 and 38.4 in the first season; and the mean of the six seasons were 36.4 and 35.8 kg ha-1 respectively. The lowest net Iiveweight production (second season) and the least deviation from the mean (first season) were higher in 93.4 and 222.7%, respectively, than those from a sheep raising system in the zone, in accordance with the rare bibliography published reporto

Keywords: sheep production system, mediterranean zone, semi-extensive sheep production, rangelands systems.
1 Centro Experimental Cauquenes (INIA), Casilla 165, Cauquenes, Chile.
2 Centro Regional de Investigación Quilamapu (INIA), Casilla 426, Chillén, Chile.