I. Dufrasne et al., EFFECTS OF A GRAZING PERIOD ON PERFORMANCE OF FINISHING BULLS - COMPARISON WITH AN INDOOR FINISHING SYSTEM, Animal Science, 60, 1995, pp. 75-80
A comparison was made between two different finishing systems with Bel
gian Blue bulls. Two groups of bulls were grazed during an initial 140
-day period and then finished indoors with concentrates. There were tw
o stocking rates during the grazing period: a medium at six bulls per
ha (MGFI) and a high at eight bulls per ha (HGFI). A third group of bu
lls was finished indoors on a concentrate diet during the whole finish
ing period (FI). The experiment was repeated over 2 years consecutivel
y. The pasture which was grazed at the medium stocking rate was charac
terized by a higher sward height (P < 0.01), more refusals (P < 0.001)
, less Lolium perenne (P < 0.05) and more Trifolium repens (P < 0.05)
than that grazed at eight bulls per ha. The live-weight gain was 1.15
kg/day during the grazing period for the MGFI bulls and 1.00 kg/day wh
en they were taken indoors. The increase in stocking rate reduced the
gain at grass (1.00 kg/day, P < 0.001) and improved the gain indoors (
1.24 v. 1.01 kg/day, P < 0.001). In the groups which were initially gr
azed when compared with the indoor system, the fattening period was lo
nger (236.0 and 241.0 v. 186.9 days, P < 0.01) and the live-weight gai
n lower (1.11 and 1.10 v. 1.44 kg/day, P < 0.001 for MGFI, HGFI and FI
respectively). The dressing proportion was greater also (P < 0.05), a
nd there were higher concentrations of muscles (P < 0.05) and bones (P
< 0.05) in the carcass of the bulls which were grazed initially. With
these bulls, the lean meat was darker (P < 0.05) and lost more water
although there were no effects on the myoglobin content or on shear fo
rce. The net profit was in favour of the groups which were grazed.