Stress in transported sheep

Abstract

Sheep are widely transported around the world, with low (0.018%) mortality rates for slaughter lambs within the UK but high (2.2%) for lambs shipped from Australia to the Middle East. Transport of animals is a multifactorial stressor, road and driving conditions, noise, vibration, atmospheric conditions, ventilation, intransit space allowance, journey length and water and food deprivation all being potential individual stressors. Changes in heart rate, plasma cortisol and prolactin suggest that sheep are stressed at the beginning of journeys but soon adapt to the conditions provided they have sufficient room to lie down, i.e. τ; 0.25 m² per lamb or about 140 kg/m². Plasma creatine kinase activities suggest that the incidence of serious injury and exhaustion are rare in transported lambs. Provided environmental conditions are not excessively hot, sheep cope well with a lack of water on journeys as long as 24 h. However, they do show signs of hunger with increased time spent feeding immediately after journeys longer than 8 h and increases in both free fatty acids and βs-hydroxybutyrate as journeys progress. Providing short rest periods with food and water within a long journey may not be advisable because sheep feed rather than drink or rest and the lamb’s fluid balance may be upset, so lowering sheep welfare. However, a longer (12 h) lairage may be beneficial.