Abstract: IN A previous communication (Clandinin et al., 1959) it was shown that the use of high processing temperatures during expeller extraction of rapeseed adversely affects the feeding value of rapeseed oil meal for poultry. The main effect of excessive heat treatment appears to be that of reducing the lysine content of the meal. The purpose of this paper is to report on studies dealing with the effects that normal variations in cooking and conditioning temperatures, used during expeller processing of rapeseed, have on the fat and lysine content of rapeseed oil meals. MATERIALS AND METHODS Sixty samples of rapeseed oil meal representing the daily run of rapeseed oil meal from each of three expellers on twenty days in May and June were obtained from a processor2 in the province of Saskatchewan. Cooking and conditioning temperatures were recorded at the time the samples were taken. On arrival at the laboratory the …