How Best to Compare Low and High Input Pastoral Systems

New Zealand dairy farm systems are changing. The traditional seasonal all-pasture system reliant on rainfall for success is now but one of a range of systems adopted by farmers, others include various levels of nitrogen fertiliser and introduced feed, both on and off farm, split calving systems and once-a-day milking. Despite these changes pasture is a critical input to almost all systems so pasture growth and utilisation are still key factors in successful dairy farm businesses. The dilemma for the dairy industry is whether or not such changes are threatening New Zealand's coveted position as a low cost producer of milk able to compete in global markets. There is also some confusion of how to define a high input system due to the fact that all the current systems have evolved from a pasture-based system. Recently two students at Massey University, New Zealand, analysed the same dataset of dairy farm data, each for slightly different reasons. The conclusions drawn from their research differed with respect to the impact of intensification on farm performance. The reason their results differed was that they used different approaches to measure the impact of intensification; each approach was soundly based on a logical argument so, in isolation, could not be faulted. This paper has been written to consolidate these results and to attempt to provide some rationale for the differing approaches taken and some direction in their interpretation and comparison for farm decision makers.