30 June 1995

Finding out what stresses

sheep most

New rules on long-haul transport of stock demand increasing vigilance on matters of animal welfare while stock is in transit. Rebecca Austin and

John Burns report on the latest research findings on what happens to sheep and other species on their way to the abattoir or new farm destination

SHEEP are less stressed when transported for 24 hours than when loaded and unloaded more than once during the same period.

The finding is the result of extensive research and is said to offer a compromise between stress at loading and unloading and excessive hunger. It was also considered when animal transport legislation was decided in Brussels last week (panel opposite).

The rules encompass research evidence that favours a rest period. But there is concern in the industry that the one-hour break in journey time set out in the new rules is insufficient

"How do you feed and water several hundred animals within an hour?" asks vet Julian Earl, chairman of the Sheep Veterinary Society working party on transport.

Stress research

Currently four UK centres research stress during transport: Bristol University, Cambridge University – in collaboration with the Babraham Institute – Edinburgh University and Bedfordshire-based Silsoe Research Institute.

Gathering and loading sheep was found to cause stress due to strange people, sheep, vehicles and dogs.

"Sheep dislike anything strange and they react badly to what are clearly painful events," says Mr Earl.

Trials show an 8% loss in body weight when food and water is withheld for 24 hours. This is likely to be due to urinary, respiratory and gut fill/faecal losses rather than fluid loss, says the trial report.

It presents no evidence of dehydration in either transported or untransported lambs and says the weight loss could be associated with increasing hunger rather than any physical deterioration of the lambs.

"This view of sheep being tolerant of adverse feeding and watering conditions is consistent with other work done on sheep in various countries," says Mr Earl. "It is what one might expect of an animal that is basically a desert species passing concentrated urine and dry faeces."

Even though blood samples show that lambs succumb to short-term stress after loading, trials show no measurable differences between groups travelling for three hours up to 24 hours if they can lie down and rest during the journey.

Even so, trials show a lamb is four times as likely to die during transit when it comes from an auction mart when it can travel three times the distance to the final destination as opposed to direct from the farm.

Legislation now states shorn sheep under 55kg require 0.2m sq to 0.3m sq (2.1ft sq to 3.2ft sq) during transit. When unshorn, space requirements increases to 0.3m sq to 0.4m sq (3,2ft sq to 4.3ft sq) for the same weights. This tallies with research at Edinburgh University which recommended 0.25m sq (2.7ft sq) for a 35kg sheep as the minimum stocking density required to enable sheep to lie down and rest as much as possible during the journey.

When they can rest sheep can recover from stress brought on during loading. "Sheep lying down are resting and should be able to tolerate journeys better than those unable to rest," says a trial report.

Heart rate is also a useful measure of short-term stress (see table). "It shows how sheep adapt to strange surroundings and events," says Mr Earl.

Research also emphasises the importance of the ventilation requirements in the new legislation. It shows that when temperature is kept below 25C (77F) humidity is not important and that at low levels of humidity sheep can cope with high temperatures.

24-hour recovery

Introducing a 24-hour recovery phase into the regulations will ensure lambs recover from short-term stress and dehydration as proven by researchers. But even though journey length has no effect on the time required for lambs to recover, trials show they do not return to pre-transport condition until six days later.

"Species differences must be allowed for in any rules," says Mr Earl. "Sheep of different ages have different requirements as do shorn versus unshorn sheep and those of slaughter weights compared with culls.

Avoid transport

"In the case of sheep going for slaughter it would be best if transport was avoided completely by the use of a mobile abattoir."

&#8226 Julian Earl is presenting a paper, Do Sheep Suffer During Transport? at the World Sheep and Wool Congress at Malvern on Aug 1.

Sheep heart rates during 18 hour 30min journey

Rate per min

Home farm, unusual


Journey to docks100

On ferry75

Journey to lairage


Lairage (first day)123

Lairage (second day)106

Second journey95

Source: Cambridge University.


&#8226 Maximum journey limit in basic trucks: Eight hours for all animals followed by a 24-hr rest period. Individual countries can impose an 8-hr maximum limit for slaughter animals with no further journeys.

&#8226 Journey times can be extended when vehicles meet certain standards (see chart below). All journey times start from the farm gate.


Calves and 9hrs1hr (min)9hrs24hrs*

lambs still for watering

on a milk diet;if necessary

unweaned feeding. Animals

pigletsnot unloaded


Adult cattle; 14hrs1hr (min)14hrs24hrs*

sheep for watering,

and, if necessary


* During this rest period animals must be unloaded, fed and watered.

&#8226 In special cases, the maximum journey times listed above can be extended by two hours when the final destination can be reached in that time.