CHOOSING APPROPRIATE SPACE ALLOWANCES FOR SLAUGHTER PIGS TRANSPORTED BY ROAD - A REVIEW

In the United Kingdom pigs can spend up to 11 hours in transit to slau ghter but on average travel for two to three hours. In the past, inter national journeys have lasted up to 40 hours and have been over 900 mi les long. There is evidence that pigs, like calves and sheep, but unli ke adult cattle, prefer to lie down if provided with suitable conditio ns, particularly bedding, on the vehicle. They will, however, sometime s stand during short journeys, possibly when excessive vibration or un comfortable flooring, particularly a lack of sufficient bedding, cause discomfort. Current UK legislation and EU Directive 95/29/EC specify that, in general, pigs must have sufficient space to lie down during t ransit. Measurements of the space needed for sternal recumbency, and d irect observations of pigs at different stocking densities, suggest th at the minimum space required is equivalent to about 250 kg/m(2) for n ormal slaughter pigs of 90 to 100 kg liveweight, This figure may not b e appropriate for very small or very large pigs, In the UK at present, more than half of all slaughter pigs are transported at densities gre ater than that prescribed (235 kg/m(2)) in the EU Directive. At stocki ng densities above about 250 kg/m(2) there may not be enough room avai lable for all the pigs to lie down, leading to continual disturbance o f recumbent animals by those seeking a place to rest. A stocking densi ty of 322 kg/m(2) leads to clear evidence of physical stress. During l ong journeys (greater than or equal to 25 hours) meat quality is reduc ed by high stocking densities, implying muscle glycogen depletion and possibly fatigue. Higher stocking densities are also associated,vith h igher mortality. There is evidence of wide variations in air temperatu re inside transporters, particularly for international journeys. Altho ugh there are small variations within vehicles, the temperature of the air inside is closely related to the outside temperature, It has been recommended that the temperature within the vehicle should not exceed 30 degrees C in order to remain within the pig's thermoneutral zone. Such temperatures, together with acceptably low concentrations of pote ntially noxious gases, such as carbon dioxide, can be achieved in movi ng vehicles by adequate ventilation, provided there is adequate space above the animals' heads. In triple-decked lorries, the height between decks has tended to be reduced and can be as little as 90 cm, Further work is needed to decide whether this is sufficient for modern slaugh ter pigs.