Hot tips on how to beat the big chill…
Reducing lamb mortality from chilling depends
on vigilance and appropriate treatment. Jonathan Riley reports
CHILLING is the greatest cause of death in young lambs but extra vigilance and simple remedies can redress the problem rapidly.
David Henderson, head of clinical studies at the Moredun Foundation, Penicuik, Edinburgh, explains that lambs are born with a source of energy called brown fat. This is burnt up in the first few hours after birth, providing heat and energy.
But, if the lamb does not receive colostrum during the first two to three hours after birth, it is prone to hypothermia.
"To reduce the risk of hypothermia the first step is to ensure that lambs have sufficient colostrum intake during the first few hours of life," he says.
Smaller, weaker lambs should be fed colostrum and then milk by stomach tube until strong enough to feed on their own.
"Chilling can occur in any lamb, indoors or out, but it is a greater risk in cold, wet and windy conditions. Chilled lambs will not feed and hypothermia can set in very quickly. These lambs must have their temperatures checked."
He says that the normal temperature of a very young lamb fluctuates between 38C (100.4F) and 39C (102.2F).
Lambs with a temperature between 37C (98.6F) and 39C (102.2F) should be dried off using a towel and fed until well enough to return to their mother.
"When the lambs temperature falls below 37.5C, first establish whether it is over five hours old. When it is under five hours old it should still have some brown fat providing it with energy and can be placed in a warming box and checked every 20 minutes. Then it can be fed until it is able to feed from its mother.
"A chilled lamb over five-hours-old will be hypoglycaemic and will need an energy source before it is put into a warming box because the sudden warmth will raise its metabolism and increase its demand for energy," says Dr Henderson.
He suggests that if the warming box is too warm it increases stress on the lamb. The aim of the box is to provide a background temperature so that the lamb does not lose heat.
"When the lambs head is up it should be able to swallow. Energy can then be supplied with 50ml of milk or colostrum for each kg liveweight by stomach tube before putting it into a warming box.
"But when the lamb is unconscious it will not swallow and so cannot be given colostrum by stomach tube," says Dr Henderson.
He advises that unconscious lambs should be given dextrose – warmed to body temperature to prevent further chilling – by injection into the abdominal cavity just above and to one side of the navel.
"This is a simple task but training should be given initially to improve operator confidence and reduce stress on the lamb," he says.
"Once the lamb has been treated successfully it still requires diligent after care to ensure it does not become chilled again," he adds. *
Young lambs can be easily chilled, particularly during cold, wet, windy conditions, warns David Henderson. Hypothermia can quickly set in.
• Under five hours old – place in warming box
• Older lambs will need feeding – milk or colostrum
• Older, unconscious lambs – inject dextrose
• Ensure warming box is not too hot
…and beware of wind plus rain – a lethal combination
WIND and rain together are the greatest enemy for newly-born lambs outdoors.
The first 24 hours of life are the most crucial to lamb survival, but the combination of wet and cold can quickly cause hypothermia and pneumonia.
The Met Offices Lamb Wind Chill Service gives shepherds information on whether shelter should be given to new lambs, explains Norwich Weather Centre commercial manager, Stephen Barker.
"The combination of rain and wind means lambs become colder much more quickly. The Wind Chill Service calculates the risks using temperature, wind speed and rain forecasts, then produces a stress factor which can be used to decide whether or not to give lambs shelter."
The stress factor index (see table) is calculated every four hours. Shepherds can either receive this as a daily forecast, which costs £30 a day, or, more commonly, receive a phonecall or fax to warn them of the onset of bad weather. The warning service costs £150 a month, and details on either service can be had from local weather centres (see map). *
Stress factor index
Good-sized singles Weaker lambs, twins and triplets
Below 80No dangerBelow 70Little danger
Above 95CriticalAbove 90Critical
The Met Offices Lamb Wind Chill Service provides regular weather risk forecasts for young lambs.