Lauri Kettunen

Simulation model for the structure of Finnish agriculture

The simulation model for the structure of agriculture makes up one part of the Finnish food model. The structure of agriculture is described in the model by the agricultural population as well as by the number, the average size and distribution of all the farms, dairy farms, pig farms, poultry farms and non-animal farms. The agricultural population is calculated by forecasting its share from the total population as a function of GDP. The number of farms is derived from the agricultural population by assuming that the size ofa farm family is constant. The average size of the farm is derived by dividing the total acreage by the number of farms. The distribution of farms is forecasted by applying a logarithmic normal distribution function. The starting points for the structure of animal production are the consumption forecasts and self-sufficiency targets. The development of the average yield per animal is forecasted by applying a trend line. Also the average size of animal farms is forecasted by a trend. The number of animal farms is obtained simply by dividing the number of animals by the average farm size.

Feed efficiency and its development in animal production

Feed conversion rates and their development are needed for the determination of the total animal production after the total feed production is known or forecast. The feed conversion rates for the period 1971 —75 were estimated from the feed balance sheets which show the feed use for different animal production lines. They form the basis for the forescasts of the coefficients for 1975 85. Feed efficiency in milk production is expected to improve by 3 per cent from 0.837 to 0.811 feed units per litre of milk in ten years by 1985. This is a result of the increase of the average yields and average weight of cows; the proportion of the feed needed for the maintenance of the cow decreases. In beef production the feed efficiency is expected to worsen, from 12.0 to 13,8 feed units per kg due to the increase of average slaughter weights. If the slaughter weights do not rise as much as predicted (from 160 to 190 kg in ten years), the feed conversion rate will not increase as predicted. In pork production the feed efficiency is expected to improve from 5.28 to 4.77 feed units per kg and in broiler production from 4.00 to 3.60 feed units per kg. All values presented above are gross estimates, i.e. they include the waste in handling and feeding. The error of the coefficients may be several per cents but it cannot be specified. The possible error has to be kept in mind when the conversion rate estimates are applied.