2012 Volume 4 Issue 1-2 Pages 89-96
This study was performed to establish effective grazing management for pigs in abandoned forest land（dominant trees: Cryptomeria japonica D. Don and Buxus microphylla Siebold et Zucc. var. sinica Rehder et E.H. Wilson, 10 a）; the study period was August-January 2012. The study population comprised 3 pigs（average body weight, 35kg; age, 20 weeks）who were provided ad libitum access to self-supplied fermented feed consisting of unhulled rice grain, rice bran, food waste, soybean curd residue silages, soybean curd residue, and boiled brown rice. The behavior and growth rate of the pigs and weed control were assessed.
The analysis showed that the dominant understory species was Pueraria lobata（Willd.）Ohwi. The pigs spent approximately 50 ％ of the day in rooting. The plant coverage and herbage mass were significantly lesser in the grazing plot（10 a）than in the control plot（closed area, 2 a）on the 32th day after grazing（P<0.05）. However, Sasamorpha borealis and Pleioblastus Simonii（Carriére）Nakai coverage was similar for both plots. The weight of 2 of the pigs decreased soon after grazing, and therefore, grazing for one of these pigs（lighter animal）was closed when it was 26 weeks old. In contrast, the other pig and the pig whose weight did not decrease showed an increased growth rate later, and their body weights were 105 kg and 85 kg, respectively, at the end of the grazing period（age, 41 weeks）.
These results indicate that, although some pigs showed growth retardation soon after grazing, small-scale swine production involving grazing of pigs for weed control in abandoned forest land might be feasible in combination with the use of rice grain-based self-supplied feed.
