Dairy farming in the Swart/and, one of the regions in the. Western Cape Province where milk is produced, was until the last decade a very important source of cash flow in farming, in contrast with wheat and sheep farming which produces an annual income. Presently the average size of a dairy is approximately 300 to 450 cows in production. In exceptional cases, there are even larger herds of900 to 1000 cows in production. Feeds such as silage and grain are self produced but cows are fed in a feedlot. Dry cows and heifers, however, graze on winter grasses such as oats and on stubble lands during summer. The long, dry and hot periods during summer go hand in hand with the Swart/and and do not allow dairy farming on permanent grazing. An economical case study was done on feedlot dairying. The results showed that nearly one third of the dairies operate at a loss, while a third run on a low profit. The profit in the top third was satisfactory. Results indicate that there is a need for research to determine whether it is possible to find methods to: • improve the effectiveness of the dairy industry • co-ordinate with a crop rotation in order to produce more feed • incorporate dairy farming in a supplementary relationship in the farming system to improve profits. The first step will be to identify the limiting factors i.e. management, feeding, sheltering, etc to optimise production efficiency and to expose it to the other overhead limiting factors to put the sustainability to the test, that is, overall farm planning. Dairy farming is a long-term activity and therefore the research in sustainability should at least correspond with the rotation of the annual crops to incorporate the dairy. An optimising technique which can be implemented in this regard is Dynamic Linear Programming (DLP).