Compensatory growth in Belgian Blue bulls previously maintained at two growing rates on pasture: animal performance and meat characteristics

A comparison was made between finishing systems with Belgian Blue bulls of the double-muscle type, in order to assess the response in terms of compensatory growth when bulls were grazed at a high stocking rate. Two groups of 8 bulls (256.5 kg liveweight) were grazed on Lolium perenne and Trifolium repens pasture during an initial period of 135 days (period I). One group grazed at a stocking rate of 6/ha allowing for normal growth at pasture (NGP); the other group grazed at a stocking rate of 10/ha (low growth at pasture, LGP). Both groups were then finished indoors (period II) with a concentrate based on dried sugarbeet pulp. Eight control bulls were also finished indoors on the concentrate diet during periods I and II (CG). Bulls were slaughtered according to a similar finishing state. Liveweight gains were 1.47, 1.10 and 0.52 kg daily (P<0.001) during period I in CG, NGP and LGP groups respectively. Corresponding liveweight gains during period II were 1.22, 1.37 and 1.50 kg daily. The LGP group had lower feed conversion ratios, slaughter weights (P<0.05) and dressing proportions (P<0.01). The meat from the grazed bulls had lower cooking losses (P<0.05) and tended to have lower drip losses and higher tenderness. It also had a higher cholesterol (P<0.05) content. Large differences were observed in the fatty acid composition according to fat location (subcutaneous, intermuscular or intramuscular). The proportions of mono and polyunsaturated acids increased in the adipose tissue of those previously grazed.