Characteristics of Rice Hulls, Sawdust, Wood Shavings and Mixture of Sawdust and Wood Shavings, and Their Usefulness According to the Pen Location for Hanwoo Cattle

In this study, two experiments were conducted to investigate the physicochemical characteristics (Exp. I) of bedding materials such as rice hulls (RH), sawdust (SD), wood shavings (WS) and sawdust+wood shavings (S+W; 1:1 in volume), and utilization of these beddings except RH (Exp. II) for rearing beef cattle. In Exp. I, the distribution of particle size (%) with $250{\mu}m$ and below $250{\mu}m$ was greater (p<0.05) in SD (30.4) than RH (4.4), WS (18.8) and S+W (20.1). Bulk density ($kg/m^3$) of bedding materials was directly proportional to the percentage of $250{\mu}m$ and below $250{\mu}m$ particles, 178, 46, 112, and 88 for SD, WD, S+W and RH, respectively. Water absorption rate (%) after submersion in water for 24 h was higher (p<0.05) in WS (540.2) compared to SD (270.2), S+W (368.2). The S+W had an intermediate value of the absorption rate between SD and WS, but had an outstanding durability of water absorption capacity. Moisture evaporation rate (%) for 12 h was higher (p<0.05) in WS (75.4) than SD (70.5), S+W (72.2) and RH (57.8). Average ammonia emission ($mg/m^2/h$) for 36 h was higher (p<0.05) in RH (3.15) than SD (1.70), WS (1.63), and S+W (1.73). In Exp. II, thirty six Hanwoo cows were allocated in 9 pens with one side on feed bunk side (Side A) and another side equipped with water supply (Side B) for 3 weeks with duplicated periods. Average moisture concentrations (%) of beddings were higher (p<0.05) in WS (side A, 65.7; side B, 57.9) than SD (side A, 62.5; side B, 52.2) and S+W (side A, 61.6; side B, 50.7). Regardless of types of beddings, moisture concentrations (%) of beddings within a pen were lower (p<0.05) at side B than A, implying longer period of utilization. These results suggest that using S+W would be a better choice than SD or WS alone, considering physicochemical characteristics and economics, and RH is not a suitable material as a bedding for beef cattle.