Effects of concentrate or ryegrass-based diets (Lolium multiflorum) on the meat quality of lambs grazing on semi-natural pastures

Abstract

With the objective of studying the effects of production systems on meat quality, 75 Norwegian White Sheep lambs were subjected to one of the following treatments: continuous grazing on a semi-natural lowland pasture until slaughtering (Control); continuous grazing followed by either stall-feeding on concentrate and grass silage or grazing ryegrass pasture for 44 or 24 days before slaughtering (Conc44, Conc24, Rye44, Rye24). Loin samples of M. longissimus dorsi including the subcutaneous fat were analysed for sensory attributes and fatty acid composition. Compared with the control group, a lower intensity of acid taste (P<0.05) and a lower content of C18:3n-6 fatty acids (P<0.001) were observed in the Conc44 group. The n-6/n-3 ratio was higher (P<0.001) in meat tested from the concentrate treatments compared to the ryegrass treatments. These findings indicate that the fattening of lambs on improved pastures or a concentrate-based diet prior to slaughter may alter meat characteristics.