The profitability of harvesting grass silages at early maturity stages: An analysis of dairy farming systems in Norway

Abstract

Feeding forages produced by early and frequent harvests may improve animal performance. This paper evaluates how harvesting regimes (HRs) in grass silage production influence optimal use of inputs and profitability in two types of Norwegian dairy farming systems: a mountain grassland farm and a lowland mixed crop–livestock farm. A whole-farm linear programming model was developed to compare three HRs within each farm type. HR1 and HR2 were three-cut systems harvested at very early (HR1) or early (HR2) crop maturity stages producing highly digestible forages. HR3 was a two-cut system returning higher dry matter yields of medium digestibility. Input–output response relations incorporated into the model were derived from field trials (N-fertilisation × HR), conducted at two representative locations for the two farm types, and from dairy cow and finishing bull feeding experiments at various levels of concentrate feeding to supplement silage from each HR. The model maximised total gross margin of farms with 150,000 l milk quota, and housing capacity for 25 cows. Farmland availability varied from 10 to 30 ha with 20 ha as the basis. The results indicated that farmland availability profoundly influences the input intensity and the profitability of producing and feeding silages harvested at early maturity stages. At restricted land availabilities in the mountain, the three-cut silages were obtained at too high costs in terms of lower grass yield, increased harvesting costs, and costs of shorter ley life. Silage DM consumption per head also increased with increasing digestibility. Under HR1 and HR2 it was impossible to fully produce the quota with 20 ha farmland and overall mountain farm profitability was depressed. With more land available, sufficient quantities of three-cut silages were produced to take advantage of the enhanced animal performances. Within all HRs, grass yields were highest in the lowland. The profitability of HR3 in the lowland was limited to smaller land areas, and, generally, producing highly digestible silages of HR1 was more profitable than devoting more land to barley. For both farm types, inputs of fertilisers and concentrates declined as more land became available, but at lower land areas for HR3. Removal of the milk quota constraint resulted in higher milk yields per cow, and strengthened profitability of HR3 endured into larger farmland areas than with a quota. With abundant land available, however, the three-cut silages were relatively more profitable without rather than with a restricting quota, and HR1 outperformed HR2.