Farm Table says:
The profitability of grazing crop stubbles may be over-estimated by using the 2 metabolisable energy intake from the stubble
What was the problem?
The authors hypothesized that costs associated with this grazing stubbles are highly variable and “grazing crop stubbles would increase farm profit by an amount equivalent to the value of the 18 metabolisable energy (ME) consumed by sheep when they grazed the crop stubbles.
What did the research involve?
- Mixed farms in two locations in Western Australia (Cunderdin and Geraldton) were compared at two stocking rates and whether or not sheep were allowed to graze stubbles.
- Simulation analysis through a biophysical farm model using the CSIRO Common Modelling Protocol
- Modelled enterprise comprised 7 x 200 ha paddocks in a 7 year crop and 79 pasture rotation sequence (annual pasture, wheat, wheat, canola, lupin, wheat, wheat), 3 x 200 ha paddocks assigned to a permanent pasture (containing lucerne) and 2 x 5 ha feedlot paddocks (one feedlot for maintaining ewes when other forage options were exhausted, and one feedlot for finishing lambs).
What were the key findings?
- Value of the ME intake from crop stubbles $39/ha, compared with increase in the farm gross margin of $18/ha, for simulations where stubble grazing was permitted.
- Owing to reduced consumption of grain by livestock, whole farm water use efficiency of protein production was increased by 15% when grazing of crop stubbles.
Farm gross margin decreased by $15/ha at Cunderdin and $20/ha at Geraldton when crop stubbles were excluded from grazing.