New fat index prompts fresh look at profits

It follows a recently completed imported feed trial at the Northland Agricultural Research Farm (NARF) in Dargaville. This looked at how farmers could reduce their reliance on imported feed by comparing two farmlets using only home-grown feed (pasture only farmlet and cropping farmlet) with a third farmlet importing PKE to fill feed deficits (PKE farmlet).  

Production and profit were measured on each of the 28ha farmlets and during the first two seasons the pasture only farmlet matched the PKE farmlet for profit despite lower production. However a wet spring in the third year had a huge impact and the pasture only farmlet finished the season with much lower production and profit than the PKE farmlet.

The cropping farmlet struggled, needing 20-25% of the farm in crops (maize, turnips and fodder beet) and had the lowest profit in all three years, highlighting the cost of losing ground to growing crops on the milking platform.

The table above shows the milksolids production and profit for each of the farmlets.These results confirmed that inputs of PKE can be very profitable during short periods of feed deficit. Strict decision rules are followed to get high responses to the supplement (over 100g MS/kg DM of PKE). 

The introduction of a fat evaluation index (FEI) this season by Fonterra is likely to restrict PKE feeding, and farmers are considering either cutting PKE out of their systems or feeding more expensive supplements during times of high demand.

The new NARF trial looks at the profitability of these strategies under another three-farmlet comparison.

The 84ha farm has been randomly split again into three 28ha farmlets of similar soils and pastures. The pasture only farm has 2.7c/ha and can only feed pasture silage made on farm.  The PKE only farm has 3.1c/ha and can feed PKE to fill deficits as long as FEI is acceptable. The PKE plus farm also has 3.1c/ha but can buy other supplements to add to the PKE if FEI levels are limiting. 

The pasture only and PKE only farms will test other options and impacts of managing feed supply shortages such as OAD milking, early culling, drying off, etc. The PKE plus farm will compare using other imported supplements such as soya hulls or DDG to fill feed gaps. The system trial allows all costs to be captured and the extra labour and capital requirements of each system will be included in the analysis. 

FEI

The Fat Evaluation Index has been developed by Fonterra to monitor the likely effect of PKE feeding on the composition and manufacturing properties of milkfat produced on farm. Farmers receive an FEI classification for each consignment of milk, based on a rolling six-day average screening test. If this result is over a certain threshold, the milk will be tested via a more accurate method and demerit grades may be applied.

For more details or to follow the regular trial updates go to www.nddt.nz or follow NDDT on Facebook.

• Kim Robinson is Northland Dairy Development Trust coordinator and farm consultant.