Next generation dairy systems for Canterbury: A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Agricultural Science with Honours at Lincoln University

Abstract

Within the current New Zealand dairy systems nitrogen inputs and out-puts play an ever increasing role on the dairy sectors environmental foot print. The New Zealand dairy sector has the need for a more efficient and yet comparatively profitable farming system, that will preform under tougher council regulations and nutrient leaching limit caps. This trial compared two different farming systems with the aim to reduce environmental foot print. The two systems where High Stocking rate Efficient (HSE) (5 cows/ha) and Low Stocking rate Efficient (LSE) (3.5 cow/ha). HSE recorded high production per hectare for both milksolids and pasture production (2369 kgMS/ha & 19417 kgDM/ha) pasture quality was also high (11.8 MJME/kgDM) while production per cow was lower than LSE but still competitive with current systems (474 kgMS/cow). LSE produced high production per cow (505 kgMS/cow) and recorded a high pasture intake 13.8 kgDM/cow/day. LSE milk on a per hectare competed with current higher stocked systems (1768 kgMS/ha). The LSE treatment was able to maintain high pasture quality (11.8 MJME/kgDM) through the use of stratigic mowing and conserving of feed as supplement. System nitrogen efficiencies where higher in LSE compared to the HSE. This was due to a lower intake of nitrogen per hectare (780 kgN/ha vs 576 kgN/ha) and the considerably lower nitrogen fertiliser inputs (330 kgN/ha vs 150 kgN/ha) seen in LSE which directly effected farm-gate nitrogen surplus (267 kgN/ha vs 71 kgN/ha). Each of the two systems showed the same partitioning of nitrogen to milk at 21% while partitioning to urine was 5% higher in HSE potentially due to the lower genetic merit of animals used. Under the current regulations and status the LSE system provides the best solution at lowering dairy farm environmental footprint. However if total production was to become the number one system driver then the HSE system would be right up there for systems profitability and performance.