Meat production on savannah-like grasslands (dehesas) in semi-arid zones of the province of Salamanca [Spain]

摘要

Two savannah-like grassland systems (dehesas) in the province of Salamanca (Spain), developed on decomposing slate and granite soils and used for extensive meat production, were examined over a period of three years to determine the stocking rate they could support, their indices of pasture utilization, and the metabolisable energy necessary for meat production. The effective stocking rates were 0.36 and 0.30 cows ha-1 year-1 on the slate and granite systems respectively. The energy provided by supplementary feed was the 34% of the annual nutritional requirements of the herds, but reached more than 60% in the months of greatest need. Pasture utilization was 40% on the slate soil and 38% on the granite soil. The live weight obtained per reproductive cow was between 128 and 217 kg, equivalent to a weight per hectare of 57-90 kg year-1, of which 85% corresponded to calf production. The mean metabolisable energy required for producing one kilogram of meat (live weight) was 361 MJ on the slate soil and 369 MJ on the granite soil (range 215-499 MJ), depending on the year.