Four replicates were conducted to determine the effects of tropical climate
and season on voluntary feed intake and performance of pigs and their carc
ass characteristics at 90 kg, as compared to a control environment (CE). CE
was characterized by ambient temperature of 20 degreesC and relative humid
ity (RH) of 75%. Under tropical climate, ambient temperature averaged 24.6
degreesC and RH 84% during the cool season (CTC) and 27.3 degreesC and 82%
during the warm season (WTC) respectively. Ninety-six Large White pigs were
used between 15 and 35 kg live weight (P1) and, as 36 of them were slaught
ered at 35 kg, the remaining pigs were used from 35 to 90 kg (P2). In the C
TC, neither voluntary feed intake, nor average daily gain, Feed:gain ratio
or carcass characteristics significantly differed from CE in P1 and P2 pigs
. In the WTC, the 13% decline in feed intake of P2 pigs (P < 0.001) induced
a 13% diminution in growth rate (P < 0.05). In the WTC, fat percentage of
the carcass was reduced by 3.2 units (P < 0.001), whereas less fat was depo
sited in backfat (P < 0.001) and more fat retained in leaf fat (P < 0.001),
as compared to the CTC. Also in the WTC, the reduction in the weight of in
ternal organs led to a 1.8 unit improvement in killing-out percentage (P<0.
001). Data indicated that in the tropics, growth performance varied with th
e season and that during the warm season feed intake was a major limiting f
actor to growth rate. (C) 2000 Elsevier Science B.V. All rights reserved.