EFFECT OF LIME AND GYPSUM ON URINARY pH IN CATTLE FED LIVE EXPORT DIETS

摘要

Ammonia emission is a consequence of manure decomposition. Urinary urea is broken into ammonium (liquid form of ammonia), and at high pH, is released into the atmosphere as ammonia. During live export of cattle, pneumonia is 1 of the main causes of death (Norris et al. 2003). Lack of natural ventilation, and high environmental temperatures during long haul trips to the Middles East are associated with instances of elevated atmospheric ammonia (Stacey 2001). Effluent acidification can be used to reduce ammonia volatilisation (Moore et al. 1997). Diets that are currently used for live export can result in a urinary pH around 8.0. Lime (calcium oxide), which is often used as a binder in export pellets, has the potential to form calcium hydroxide upon hydration and thus increase urinary pH. We investigated the effect of lime and gypsum on urinary pH.