The practical and economic consequences of integrating maize with grass production on dairy farms in southern England: a computer simulation

A mathematical model of the production, harvesting and utilization of maize and grass silage on a dairy farm with an autumn-calving herd is described. Using the model the comparative costs and benefits of growing and feeding maize in place of grass silage are examined for three sites in southern England. It is concluded that a winter milk production system based on maize rather than grass should improve profits by at least £30, and possibly by as much as £80 cow^-1. This financial improvement is attributable to higher feed intakes and lower harvesting and fertilizer costs with maize silage. Simulating the results over a 10-year period also revealed that the switch from grass to maize should lower the risks in terms of the annual variability of silage yields and herd profits. Furthermore, it would appear unnecessary to completely turn over from grass to maize production to realize a significant financial benefit. Setting aside just 25% of the conservation area to maize and feeding a mixture of maize and grass silage is projected to increase profits from winter milk production by £30 to £45 cow^-1.