RELATIVE GROWTH PATTERNS OF INDIVIDUAL MUSCLES IN THE PIG

Abstract

The muscle-weight distribution and relative growth rate patterns were determined for 96 muscles and nine anatomical muscle groups dissected from half carcasses of pigs from two studies. The first study involved 109 pigs representing barrows and gilts of three breed groups, fed two rations differing in energy and protein and slaughtered at weights ranging from 23 to 114 kg liveweight. The second study involved 72 pigs representing barrows and gilts of two breed groups, fed one of three levels of a low-energy ration and slaughtered at one of three liveweights from 68 kg to 114 kg. Of the 96 muscles dissected, 69 muscles each weighed less than 1% of total muscle, five ranged from 3 to 7% and one muscle was more than 10% of total muscle. Relative growth rate patterns of individual muscles and anatomical muscle groups from pigs were compared with other studies from cattle and sheep. Generally, relative muscle growth in pigs over the range in liveweight studied appeared to be more monophasic than in cattle or sheep. Relative growth rate of muscles and subsequent muscle distribution appeared to be related to muscle function. Muscles associated with mobility immediately after birth showed much earlier development than those concerned with propulsion. Muscles involved with posture appeared to grow at the same relative rate as total muscle. Key words: Pig, growth, muscle growth