Ajf Webster

Study of the behaviour, digestive efficiency and gut transit times of crib-biting horses.

The spontaneous behaviour and the apparent digestibility of dry matter and fibre and transit times of digesta were compared in four normal horses and four crib-biters. A technique was developed for measuring total gut transit times (TGTT) by using single-stool analysis of the passage of radio-opaque polyethylene markers. Longer TGTT were recorded in the crib-biters than in the normal horses but the orocaecal transit times did not differ. The crib-biters rested less than the normal horses.

Vehicle design and thermal comfort of poultry in transit.

1. Four second-generation artificial chickens (Glorias) simulated the sensible heat exchanges, H, of pullets and end-of-lay hens which they accompanied throughout commercial transit in different sites of the loads. 2. Data from two summer and two winter journeys on each of 5 naturally- and 2 fan-ventilated vehicles were used to derive general equations to predict H and temperature lift for each vehicle. 3. From these, air movement, V, within the crates was calculated together with predicted H at ambient temperatures to compare the thermal comfort of the vehicles. 4. All naturally-ventilated vehicles were over-ventilated in motion, with mean V ranging from 0.9 to 2.4 m/s within the crate, and maximum V of 6.0 m/s resulting in negligible temperature lift above ambient. Poorly-feathered hens were, consequently, extremely cold-stressed in winter. When stationary, vehicles with a central passage that enabled the stack effect to operate were thermally comfortable provided V was kept low. Designs stocked over the whole floor area of the vehicle were too hot. 5. Fan-ventilated vehicles had a similar range of H whether stationary or in motion. The mean V of 1 to 2 m/s of bird-warmed air maintained satisfactory thermal conditions most of the time. 6. For current designs of poultry vehicle stocked at commercial rates, V should normally be between 0.3 and 1.0 m/s; air temperature near pullets or broilers should be 10-15 degrees C and near poorly-feathered hens 22-28 degrees C. Suitable ventilation rates are likely to be in the range 100 to 600 m3 per hour. It is strongly recommended that appropriate temperature monitoring systems be fitted on all vehicles.

Strength of motivation of broiler chickens to seek fresh air after exposure to atmospheric ammonia

less (a group size of seven or more birds). Placing a priority for space over that for height masked any potential preferences between the two heights under investigation even at these relatively low stocking densities (1219 cm per bird, including nestboxes, when evenly distributed across the two cages). It would, therefore, be worthwhile to investigate if varying group size and available space affects both cage height preference and distribution of individual hens across pairs of cages. Avoidance of high stocking densities by hens may represent some degree of aversion to such conditions, which points to a potentially-powerful method for investigating the complex issue of behavioural priorities of group-housed hens. This could involve titrating the value of a resource against the cost of experiencing low personal space.