Sheep are widely transported around the world, with low (0.018%) morta
lity 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, jour
ney length and water and food deprivation all being potential individu
al stressors. Changes in heart rate, plasma cortisol and prolactin sug
gest that sheep are stressed at the beginning of journeys but soon ada
pt to the conditions provided they have sufficient room to lie down, i
.e. > 0.25 m(2) per lamb or about 140 kg/m(2). 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 incr
eases in both free fatty acids and beta-hydroxybutyrate as journeys pr
ogress. 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 welf
are. However, a longer (12 h) lairage may be beneficial.