An economic analysis of beef stocking rates.
ABSTRACT The Land Conversion Scheme and the prevailing maize and meat market situations have given rise to renewed interest in livestock production from cultivated pasture. The model developed by Jones and Sandland (1974) is used to determine optimum stocking rates under various circumstances. A micro-computer model, OPTSR, is developed for relatively quick solutions.
The relation between animal gain and stocking rate in grazing trials: an examination of published theoretical models
SUMMARY Jones & Sandland (1974) examined the validity of the linear model for gain per animal on stocking rate. This paper examines the alternative models of Conniffe, Browne & Walsh (1970, 1972) and a proposed extension of the model of Owen & Ridgman (1968). Discrepancies between these models and the linear model are studied in detail. Under specified conditions these models are shown to be very close to the linear model. It is concluded, from the earlier work of Jones & Sandland (1974) and these results, that the empirically justified simple linear model has the advantage of being much easier to fit as well as embodying (approximately) the theoretical advantages of these conceptually superior models under a range of assumptions.
Animal production from a Sorghum almum pasture in south-east Queensland
A grazing experiment on Sorghum almum pastures, one of which received 200 lb nitrogen an acre a year, as urea, was carried out at Lawes in south-east Queensland. Pastures were grazed continuously at three set stocking rates : 1 beast to 1 1/2 acres, 1 beast per acre, and 2 beasts per acre. Grazing commenced 3 1/2 months after sowing and continued for two years. Mean liveweight production over the whole period at the medium stocking rate of one beast per acre was 0.92 lb a head a day. Production was closely related to stocking rate : gain per head decreased and production per acre increased as stocking rate increased. Nitrogen fertilizer increased animal production at the heaviest stocking rate. Seasonal pattern of animal production was influenced by stocking rate, but, in general, a winter--early spring period of small gains or losses of weight was followed by a rapid increase in late spring--early summer, with the rate of gain decreasing from mid-summer onwards. This followed the seasonal pattern of pasture production : little or no production over the cool dry winter, but high yields of forage during summer. No close relation was detected between liveweight gain and green forage available in the period of rapid increase in liveweight. During the phase of declining pasture and animal production, liveweight increment was related to available pasture expressed as green material minus S. almum stem. Crude protein content of unfertilized S. almum varied from 15 per cent for green material in spring to 2.5 per cent for the dry forage available in winter. Urea increased both yield and protein content.