To determine the value of pasture renewal to a dairy farm system in the 2009-2010 Season
Two Waikato dairy farms were modelled over the 2008-09 and 2009-10 season. These farms were chosen because they were from the same district with similar soil types and fertiliser applications. One of the farms has undertaken the programmed approach to pasture renewal while the other has not introduced new varieties in the last twenty years.
The first step was to model the actual on farm performance using UDDER for the two seasons. This approach allows the individual aspects of the on farm management to be accounted for. Once the farm is modelled then it is possible to remove all sources of supplementary feed removed so that the only feed supply is the pasture grown on the farm.
The next step is to then calculate the stocking rate that is able to be sustainably maintained on the pasture grown by the farm. The renewed pastures were able to sustainably produce more milksolids through the increased productivity.
The direct costs required to undertake a pasture renewal has been assessed at $1500 per hectare but this is only required on 7% of the farm. When this cost is spread over the time between renewals it costs $100 per annum to renew pastures that have been accounted for in the margins production costs.
An operating margin was able to be calculated from the milksolids production. The operating margin is defined as the revenue remaining after all of the direct production costs have been accounted for including pasture renewal. The average per hectare operating margin over the two seasons modelled was equivalent to $360 per hectare.
Further work was carried out on farms in Taranaki, Canterbury and Southland for the 2009-10 seasons comparing the effect of pasture renewal on the same criteria as the Waikato farms. A similar operating margin was achieved in Taranaki and Canterbury but not on the Southland farms.
The conclusion is that where pastures are under summer stress from pests or climatic conditions there is an excellent return to pasture renewal. In a summer friendly environment such as Southland the need to renew pasture is associated with the winter management of feeding a herd.