The effect of variations in the energy and protein status of the diet upon productive efficiency in the pig

Abstract

A feeding trial is described in which 32 individually-fed Large White pigs were used to investigate the effects of variations in the protein and energy status of the diet on growth, efficiency of food utilisation and carcass characteristics. The salient features of the finding were:1. Over the weight interval 50–100 lb., it appeared that 1·0% was a more appropriate level of dietary lysine than one of the order of 0·75%; the former figure corresponded to a level of 5·8% of dietary protein.2. In the ‘finishing phase’ of growth from 100–200 lb. the pig clearly tolerates wider energy : protein ratios than is the case in earlier life, with advantageous results in terms of growth performance but deleterious effects on carcass suitability.3. An increase in dietary energy status in the ‘finishing phase’ yields growth responses only if protein level is appropriately adjusted.4. It is suggested that Large White pigs require a level of 0·5–0·6% of dietary lysine in the ‘finishing’ period.