THE ASSESSMENT OF PASTURE UTILISATION ON DAIRY FARMS

Abstract

The quantities of pasture utilised on New Zealand's predominantly pastoral dairy farms can be indirectly estimated from calculating the feed requirements of livestock on the farm and adjusting the total quantities consumed for feed purchased from off the farm. This method provides a logical and quantitative framework for analysing between farm differences in productivity and pasture utilisation. The calculations require information regarding the number, breed and categories of stock farmed; the total production of milk or milkiat; the quantities of crops, hay and silage grown and/or conserved; and the quantities of purchased feeds consumed. Reliable tables of feed requirements are available for use in such calculations. This method has been used to examine data collected in surveys of town supply and seasonal supply farms in Manawatu and South Auckland by Massey University and Lincoln College, respectively. Comparisons between districts are unreliable because the surveys were conducted in different seasons and by different sampling methods. However, the differences between farm types were similar within districts and indicated lower stocking rates and milkfat production per hectare on town supply farms. There was a large reliance on the use of home grown pasture on all farms, but town supply farms used higher proportions of crops, hay and silage than did seasonal supply farms. A wide range existed between farms in the quantities of home grown feed consumed per hectare (4.9-18.0 tonnes DM/ha on town supply farms and 6.7-17.1 tonnes DfvVha on seasonal supply farms). This method of analysis. together with estimates of potential pasture production, may help to identity situations in which increases in pasture utilisation may be capable of increasing farm productivity. Keywords: town supply, seasonal supply, grazing, Conservation, supplements, farm productivity