Effect of conserving pasture as silage on the productivity and profitability of grazing steers

Abstract

The productivity and economics of annual land use systems were evaluated by studying beef steers, continuous grazing and spring feed conserved as silage. One treatment measured the production of steers grazing annual pasture continuously from weaning in December until slaughter 12 months later. In the other treatment, cattle grazed similar pasture from December until slaughter in July at 15 months of age but in autumn were fed silage made from the spring growth on the same area. There were 2 stocking rates (0.4 and 0.5 ha per steer) and 2 replicates of the 4 treatments; the experiment ran continuously for 3 years. In all years the pasture only system cost less and produced, on average, 100 kg more carcass per ha than did the silage system and at current values was more profitable. Only when autumn pasture growth was greater than normal did the profitability of the silage system approach the pasture only system. In both biological and economic terms the pasture only system was less variable than the silage system because of the buffering effect of consistently abundant spring pastures. In years of poor growth of pasture in autumn, the silage treatment did not achieve the objective of producing premium carcasses in July, owing to their low weight and fatness. There were wide variations among years in patterns of pasture growth, and hence gross margins. Gross margin analyses were most sensitive to changes in sale price of cattle and then to changes in the cost of making and feeding silage; they were least sensitive to interest rates.