Evaluation of the growth of backfat depth, loin depth, and carcass weight for different sire and dam lines.

ABSTRACT The growth of 1,990 barrows and gilts of 3 sire and 2 dam lines was evaluated over 2 replicates. Pigs were weighed and ultrasonic backfat and loin depth measurements were taken at approximate 28-d intervals from 37kg BW to target BW of 113, 127, or 141kg. Carcass backfat and loin depths were measured with an optical probe. An exponential equation Y = exp(b 0 + b 1 X + b 2 X 2 ) + a i [exp(b 0 + b 1 BW + b 2 BW 2 )] D (where Y is the value of the measurement; b 0 , b 1 , and b 2 are regression coefficients; and D is a parameter) with a pig-specific random effect (a i ) provided the best fit of the ultrasonic data to BW. The ultrasonic backfat depths were affected ( P P P