Studies of growth and development in the young pig Part II. A comparison of the performance to 200 lb. of pigs reared along different growth curves to 56 days of age

Abstract

1. Twenty blocks of four litter-mates were individually fed under standard conditions from 56 days of age to 200 lb. Each block consisted of three early-weaned pigs reared to 50, 40 and 30 lb. live weight, respectively, at 56 days of age and a suckled pig reared to 50 lb. live weight at 56 days of age.2. There was no difference in the growth rate and feed conversion from 56 days of age to 200 lb. of the early-weaned and suckled pigs reared to 50 lb. at 56 days of age.The age at 200 lb. of the 30, 40 and 50 lb. early-weaned pigs were 169·8, 176·8 and 182·7 days and the lb. of meal per lb. live-weight gain 3·3, 3·2 and 3·1 lb., respectively. A reduction in 56-day weight led to an increase in growth rate and feed conversion from 50 to 200 lb. live weight.3. The conformation and composition of the bacon carcasses of the 50 lb. early-weaned pigs were not significantly different from the carcasses of the suckled pigs which also weighed 50 lb. at 56 days of age.An extensive examination of the carcasses of early-weaned pigs showed that an increase in 56-day weight from 30 to 50 lb. live weight signifieantly reduced the weight of muscle present and significantly increased the amount of subcutaneous fat. The conformation of the carcasses was not affected.