Previous studies (e.g. Cia et al. 1998) have shown that modification of body composition of the prepubertal gilt has effects on responsiveness of gilts to exogenous gonadotrophin. Growing pigs are able to select a diet from different foods differing in protein:energy ratio (Dalby 1998); however there is little evidence of what effect the conflicting nutritional demands of growth and reproduction have on diet selection. The objectives of the experiment were to quantify the effects of choice feeding on responsiveness of gilts to exogenous gonadotrophin (Cia et al. 1998) and to investigate the effect of protein source on diet selection as Jones et al.(2000) have observed selection by breeding gilts against a high protein diet containing fishmeal.