Factors affecting evaporation of water from cattle bedding materials

In livestock farming, maintaining dry bedding is considered to be important for maximising animal performance and welfare. A better understanding of the mechanisms that regulate drying has the potential to improve bedding management and reduce production costs. A custom laboratory-scale method was developed to explore the effects of environmental conditions and bedding characteristics on drying rate (DR). Samples (n = 256) of different types of bedding materials were exposed to controlled environmental conditions by using a climate chamber equipped with a custom cabinet capable of simulating different levels of air velocity and bedding temperature. The effects of the type of material, bedding moisture content, bedding temperature, air temperature, air relative humidity (RH) and air velocity were evaluated in a full factorial experimental design. Under the experimental conditions tested, DR ranged from 0.28 to 6.04 kg m−2 d−1, with an average of 2.03 kg m−2 d−1. All variables significantly affected DR, but large variation in the magnitude of effects was found. Bedding moisture content, air velocity and air RH had considerably larger effects than the other variables, together accounting for more than 70% of the variance in DR. The DR from bedding samples increased with bedding moisture content and air velocity but decreased with increasing air RH. The results of the current study may have important implications in the design and management of bedded pack barns. To increase the DR and keep bedding dry, producers should focus primarily on providing adequate barn ventilation (both in terms of air velocity and air exchange), whereas maintaining a high pack temperature may yield poorer-than-expected results.