Microclimatic conditions and their effects on sheep behavior during a live export shipment from Australia to the Middle East.

Abstract

The microclimate can potentially impact the health and welfare of livestock exported by ship. Within-pen microclimatic conditions were recorded and the effects of ammonia on sheep behavior investigated on a voyage from Australia to the Middle East. Ammonia, carbon dioxide, and hydrogen sulfide as well as wet-bulb, dry-bulb, and dew-point temperature and air speed were mapped in 20 open-deck focal pens, with the focus on the behavior and location of a marked sheep in each pen. Air speed was highly variable in most pens, with pockets of high but transient concentrations of ammonia (30.7 to 44.2 mg/m(3)) in 20% of pens that had no or minimal air flow. Carbon dioxide concentrations varied in some pens, but overall concentrations of carbon dioxide and hydrogen sulfide were low. Sheep in pens previously identified to have high ammonia concentrations, high wet-bulb temperatures, and low wind speed stood longer (P = 0.003) and spent less time feeding (P = 0.01) and ruminating (P = 0.004) than those in pens previously identified with low ammonia, low wet-bulb temperature, and high wind speed. Moreover, sheep exposed to increased ammonia concentrations held their head higher (P = 0.004) to avoid the greater ammonia concentrations at lower heights, and these sheep had more conjunctivitis (P < 0.001). Sheep movement around the pen was limited. Increased time spent lying down (P = 0.04) and more rhythmical behavior in the second half of the voyage indicated that the sheep adjusted to shipboard conditions over time. It is concluded that high, transient concentrations of ammonia existed in some pens, which adversely affected the behavior of sheep.