Figures for average growth-rate and its rate of change over the 16-week period of a nutrition exp. on 30 individually-fed bacon pigs were calculated, replacing the usual figures of live-weight gain. Analysis of variance, and covariance on initial weight, demonstrated the significance of a fall in average growth-rate with increasing protein percentage in the ration, and of a sex difference in favor of the gilts in both the average growth-rate and its rate of change.