BENEFITS AND COSTS OF HIGHER STOCKING RATES ON A COMMERCIAL DAIRY FARM IN THE MACALISTER IRRIGATION DISTRICT

In December 1993, the Macalister Research Farm began a whole-farm study to compare the benefits and costs of two systems of dairy farming, based on two different stocking rates. The farm, comprising 80 ha of irrigated perennial pasture, was split into two similar sub-farms. The herd of 250 cows was split into two sub-herds of similar average age and productive capacity. One herd was stocked at 2.6 cows/ha, the other at 3.9 cows/ha. Over the next 2 ‰ years, both herds were managed to achieve similar levels of milk production per cow and high levels of pasture utilisation. Records were kept of all inputs and outputs associated with the operation of each sub-farm. In each season, the higher stocked herd produced more milk per hectare and slightly more per cow, required higher levels of supplementary feeding and other operational inputs, and yielded higher profits than the lower stocked herd. Individual farmers have to decide whether the higher profits of the higher stocked system were sufficient to justify the extra labour and stress involved in operating the larger herd. The difference in profitability between the two systems was very sensitive to changes in the price of milk, and costs of grain and nitrogen fertiliser. The results of this study have been used to develop a ready-reckoner for use by farmers considering variations in stocking rate for their own farms