Changes in connective tissue of M. semitendinosus as a response to different growth paths in steers

The effect of growth path, as opposed to advancing age, on the biophysical and biochemical properties of muscle connective tissue was investigated. Nine-month old Brahman-cross steers were grown across either an uninterrupted path, or paths that incorporated weight-loss and then weight gain on two different diets: one group was realimented on pasture, whilst the other was realimented on a grain-based diet. Biophysical attributes of connective tissue toughness (Compression and Adhesion) in the semitendinosus muscle, were significantly reduced by treatment (P<0.05): weight loss with grain realimentation being the least tough in regard to the connective tissue component. Variance within the biophysical attributes was modelled statistically. Statistically significant models included terms for the post-slaughter connective tissue content as well as tissue contents of the enzymes lactate dehydrogenase and isocitrate dehydrogenase. The data suggest that biochemical measurements made up to 100 days prior to slaughter, may have value as indicators of final connective tissue toughness.