Primary productivity, diet quality and voluntary intake for estimating stocking rate

The aim of this study was to estimate stocking rate in open grassland considering its primary productivity, diet quality and voluntary intake of beef cattle. To achieve this, the methodology and systems analysis approach was used. By means of the Stella 8.0 simulation program a model was developed whose predictions show an 11 % of difference in the actual primary productivity respect to that estimated of 3 years with different precipitation. In the study period, the stocking rate estimated in 2000 ha in the study period according to dry matter intake, crude protein and metabolizable energy ranged between 248-663, 233-823 and 297-758 animal units, respectively. The monthly stocking rate average estimated by the model base on produced dry matter and protein crude and metabolizable energy was 247.4, 289.5 and 321.54 animal units, respectively. Stocking rate and stocking coefficient predicted by the model indicate that assigning the hectares per animal unit will meet the needs of dry matter intake but there is a deficiency of crude protein and metabolizable energy when the mean annual precipitation is equal or lower to average.