With the cold weather impact of the ‘Beast from the East’ last March still fresh in livestock farmers’ minds, sheep producers are being urged to be prepared to minimise lamb losses should temperatures fall at lambing time again this year.
"Hypothermia is one of the major causes mortality in young lambs, but if we do get a cold snap its impact on lambs can be mitigated if you are prepared to act quickly,” says Volac technical officer Abi Erian.
Ms Erian says that newborn lambs lose body heat rapidly, particularly if they are both cold and wet. “Newborn lambs have limited energy reserves and have a large surface area to bodyweight ratio, which makes them susceptible to heat loss. It also means they lose heat at a much higher rate when they are wet than when they are dry.”
She adds that any lambs that do not feed within the first few hours after birth will soon run out of energy reserves to keep warm. “Lambs that don’t feed will die rapidly if there is no intervention – no matter what environment they are born into.”
Ms Erian says that signs of hypothermia include a hunched posture, hollowed out sides, excessive bleating, lethargy and dehydration.
“In newborn lambs hypothermia usually results from exposure. In older lambs it is typically as a result of starvation. If you pinch a lamb’s skin over the spine it should snap back almost immediately. But if the skin stays in place like a tent, the lamb is dehydrated and needs immediate attention,” she says.
She adds that you can also take a lamb’s rectal temperature to confirm hypothermia. “Normal lamb body temperature is 39°C. A reading of 37-39°C indicates mild to moderate hypothermia and if the thermometer shows below 37°C, the lamb is severely hypothermic.”
Treatment for hypothermia should vary, depending on an affected lamb’s age and body temperature.“Newborn lambs less than five hours old usually have a brown fat reserve within their bodies, which acts as an energy stopgap between birth and the time a lamb is able to feed.
“Consequently, these very young lambs should respond to drying with a towel, warming and then feeding – with natural colostrum or a proven alternative, such as Volac Volostrum, for the first 24 hours of life and then warm Lamlac ewe milk replacer thereafter,” she advises.
Ms Erian stresses that an adequate early life colostrum intake (more than 210ml/kg) is the key to reducing losses from hypothermia in newborn lambs.
“Colostrum is particularly rich in proteins, which carry specific antibodies that help protect the lamb from infections. It is also high in energy, which will help the lamb maintain body temperature.”
Protecting older lambs
Lambs over five hours of age have used up their brown fat reserves, so it is important that they are given energy before being warmed.
“If the lamb can hold its head up, feed it before warming under a heat lamp. If it is too weak to lift its head, seek advice from a vet about administering an intra-peritoneal glucose solution via injection. After any injection, warm the lamb under a heat lamb until its rectal temperature reaches 37°C after which it can be fed. Feed colostrum or a colostrum alternative for the first 24 hours and thereafter feed a warm milk replacer, such as Volac Lamlac,” Ms Erian says.
And a few ‘DON’Ts’ during cold weather:
- Do not submerge a hypothermic lamb in warm water. This will raise the lamb’s body temperature too quickly and also wash the scent off the lamb, making the ewe less likely to reclaim it.
- Do not feed a cold lamb under five hours old. Warm the lamb before feeding. A hypothermic lamb can’t digest milk/milk replacer and the food will just sit in the stomach and cause problems.
- Do not warm a lamb over five hours old with low blood sugar. If lamb is unable to hold its head up, energy via a glucose injection may be required. Seek the opinion of your vet.
- Do not overheat a lamb. Warming a cold lamb too quickly can cause death.