Compensatory growth in Belgian Blue bulls previously grazed at two stocking rates: animal performance and meat characteristics

Abstract

A comparison was made between fattening systems with Belgian Blue bulls of the double-muscle type, in order to assess the reponse in terms of compensatory growth when the bulls were grazed at a high stocking rate. Two groups of eight bulls 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 six animals per ha allowing for normal growth at pasture (NGP); the other group grazed at stocking rate of 10 animals per ha (low growth at pasture, LGP). Both groups were then finished indoors (period II) with a concentrate based on dried sugar-beet pulp. Eight control bulls were also fattened indoors on the concentrate diet during periods I and II (CG). The bulls were slaughtered according to similar finishing fattening state. Live-weight gains were 1·47, 1·10 and 0·52 kg/day (P < 0·002) during period I in CG, NGP and LGP groups respectively. Corresponding live-weight gains during period II were 1·22, 1·37 and 1·50 kg/day (P > 0·05). The LGP group had lower food 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 (P > 0·05) and higher tenderness (P > 0·05). 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 were increased in the fats of the animals previously grazed (P > 0·05, P < 0·05).