Use of irrigated pastures in semi-arid grazinglands: A dynamic model for stocking rate decisions

Simulation results were close to observed values for northern Mexico with regard to annual yield of dry standing crop (21,434 vs. 23,637 kg ha−1), dry matter digestibility (67-78% vs. 70-74%), and optimum stocking rate as live weight (892-2567 vs. 2250 kg ha−1). Simulation results indicated the highest optimum stocking rate was 2567 ± 62 kg ha−1 in July and the lowest was 892 ± 106 kg ha−1 in January. The highest daily gain per head was 1.144 ± 0.006 kg in February and the lowest was 0.480 ± 0.052 kg in July. Daily forage allowance for the optimum stocking rate varied during the year from 4.05 ± 0.053 in July to 4.84 ± 0.008% of live weight in January. Producers should maintain a herd size that allows maintenance of the optimum stocking rate during months of low growth and, during months of high growth, should graze only the area required to cover the recommended forage allowance, and cut the rest of the forage.