PROTEIN LEVELS FOR GROWING BOARS ON PASTURE AND CONCRETE DRYLOT

Abstract

A summary of feed consumption data (Lasley and Hazel, 1953) for 77 growing boars fed individually and 72 growing-finishing barrows and gilts of similar breeding fed in groups of 4 showed that the boars consumed a higher proportion of supplement to shelled corn when fed free choice. If true protein needs are reflected by self-selection, these data suggest that boars require about three percentage units more protein in their rations than do the other sexes. Knowledge of the specific protein requirements of boars is desirable in view of this evidence and the increased interest in evaluation of boars at central testing stations. This paper summarizes an experiment designed to determine the optimum level of protein for growing boars fed on pasture and in concrete drylot. Animals. Three replications in a 2×2×6 factorial arrangement involving two breeds (36 Poland China and 36 Landrace boars), two locations (pasture and. concrete drylot) and 6 levels of protein were used in this experiment. The average weight and age of the 72 weanling boars was 29.4 lb. and 50.3 days, respectively. Each boar was removed from the experiment at an approximate liveweight of 195 lb. A littermate pair was allotted at random to a protein level with one member randomly assigned to pasture and the other to concrete. Management. All the boars were maintained in individual pens. The boars fed on pasture were confined in portable units described by Ashton et al. 1955. These units were moved to fresh alfalfa pasture three times