초록
Three Japanese Corriedale wethers were used in a $3{\times}3$ latin square design to determine the effect of soybean meal (SBM) supplementation on the eating and rumination behavior in sheep fed rice straw as a basal diet. Soybean meal was supplemented at three levels of 0 (control), 75 g and 150 g/day. Soybean meal supplementation had no significant effect on the daily time spent eating and rumination, whereas the rate of eating of rice straw was significantly faster (p<0.05) in sheep fed SBM-supplemented diets than in sheep fed control diet. However, when expressed per 100 g of neutral detergent fibre (NDF) intake, daily rumination time of sheep fed 75 and 150 g of SBM-supplemented diets was greatly reduced (p<0.01). The length of each rumination period, daily number of rumination periods and number of boli regurgitated were about constant for all SBM levels. Cyclic rate (rumination time per daily number of boli regurgitated) and rumination index (rumination time per 100 g of dry matter eaten) were significantly decreased (p<0.05) by SBM supplementation. The number of chews per bolus was not affected, whereas the bolus time reduced (p<0.05) and the rate of chewing during rumination was increased (p<0.05) by SBM supplementation.