Two experiments were conducted to assess effects of outdoor fattening on pigs' behavior, growth performance, and carcass traits. For each experiment, 8 pigs (WL×D) were separated equally into a control group (CG) and an outdoor fattening group (OFG). For Experiment 1, CG pigs were fattened entirely indoors (slatted floors, 1.8m
2/pig). The OFG pigs were fattened outdoors (bamboo thicket, 60m
2/pig) during 10 : 00-17 : 00, and indoors during 17 : 00-10 : 00 (1.8m
2/pig). The CG pigs were fed a commercial diet
ad libitum. The OFG pigs were fed a commercial diet restrictively (750g /pig/day) when pigs were outdoors ; they were fed
ad libitum other times. For Experiment 2, CG pigs were fattened entirely indoors (1.8m
2/pig) ; OFG pigs were fattened outdoors (30m
2/pig). Both groups were fed a commercial diet
ad libitum. Experiments ceased when the pig weight reached 105kg. Based on results of Exp. 1 OFG pigs had significantly lower feeding, drinking, and resting, and a higher behavior ratio of exercise than CG pigs had (
P<0.05). Their feed intake was lower than that of CG pigs. The OFG pigs had significantly lower average daily gain than CG pigs had (
P<0.05). The OFG pigs had longer carcass length, back loin length I, back loin length II, and loin length than CG pigs had (
P<0.05). The backfat depth (shoulder, back, loin, and three-point average) of OFG pigs was less than that of CG pigs. Based on Exp. 2, no significant differences in feeding, drinking, or behavior ratios of eliminating between were found between the two groups. However, OFG pigs displayed significantly less resting and a higher ratio of exercise behavior than CG pigs did (
P<0.05). The OFG pigs showed less feed intake than the CG pigs did. Consequently, the average daily gain of OFG pigs was lower than that of CG pigs (
P<0.05). The OFG pigs showed lower growth performance attributable to more exercise, less rest, and less intake, but carcass traits included longer loin length and thinner back fat, suggesting that outdoor fattening for pork production gives a high red-meat yield.
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