Changes in the solubility of bovine intramuscular collagen due to nutritional regime

Longissimus dorsi muscles were removed from the carcasses of 60 Charolais-cross steers in order to examine the relationship between five feeding systems and collagen solubility values obtained by two different methods (warm and cold extractions). Steers were provided with either a 75% concentrate diet, 50% concentrate diet, corn silage diet, corn silage to 400 kg live weight followed by the 75% concentrate diet or alfalfa silage fed to 400 kg live weight followed by the 75% concentrate diet. Steers on the 75% concentrate diet throughout the feeding period required the least time on feed, had the lowest slaughter and carcass weights and produced meat with the highest warm collagen solubility values. Steers fed corn silage continuously needed the longest time on feed, had the lowest daily rates of gain and produced meat with the lowest warm collagen solubility values. Despite being on feed for a longer length of time, steers fed corn silage or alfalfa silage prior to finishing on the 75% concentrate diet produced meat with warm collagen solubility values similar to those continuously fed the 50% concentrate diet. Steers fed the 75% concentrate diet subsequent to forage feeding exhibited greater rates of gain before slaughter while those fed the 75% concentrate diet continuously showed a rapid decline in rate of gain with increasing body weight. Total collagen and cold collagen values were similar among feeding systems. These results indicated that plane of nutrition before slaughter and days on feed both exerted an influence on the properties of intramuscular collagen.