Initial liveweight of fattening pigs and its relationship with productive performance in a feeding system based on concentrates and ad libitum final molasses

A total of 144 (Yorkshire x Yorkshire,: Landrace) crossbred pigs (the same number of females and castrated males) was distributed in 3 treatments and 8 replications of a random block design to demonstrate that when concentrat es and final molasses are supplied separately and ad libitum in the feeding troughs, pig performance depends on the liveweight at the start of fatteni ng (19, 29 and 39 kg) and an improvement in concentrate efficiency, is prod uced. Concentrate intake increased as liveweight increased at the start of fattening (2.34, 2.48 and 2.81 kg; P < 0.001) as well as final molasses int ake (0.58, 0.63 and 0.71 kg; P < 0.05). Daily gain also increased (677, 756 and 895 g; P < 0.001). Total feed conversion was reduced, as the initial l iveweight was increased (4.31, 4.11 and 3.94 kg/kg; P < 0.001), as well as that of the concentrates (3.45, 3.27 and 3.15 kg/kg; P < 0.001 in all cases for 19, 29 and 39 kg, respectively). Linear regression was high between li veweight at the start of fattening (X) and daily gain (r = 0.87) as well as concentrate conversion (r = 0.78). Tile use of this system allows a greate r concentrate efficiency when liveweight increases at the of fattening.