Hypothermia in lambs - The Accidental Smallholder

Hypothermia is one of the major causes of lamb mortality within the first seven days of life. It occurs when the lamb’s body temperature drops below 39C and the body’s capacity to generate heat cannot compensate for the loss of body heat.

There are two main causes of hypothermia – the environment and starvation. If the weather is wet and windy, if the ground is frozen, if a ewe fails to dry the lamb properly – these environmental conditions can lead to hypothermia, usually in lambs under six hours old.

In older lambs, the most common cause of hypothermia is starvation – and this can happen in ANY environmental conditions.

Lambs suffering from mild hypothermia may appear “tucked up” and slightly lethargic. Severely affected lambs may be comatose.

Treatment has the best chance of success if the condition is detected early and the correct treatment administered quickly.

Temperature as an indicator

It’s always a good idea to take a rectal temperature of any lamb that appears unwell. If the temperature is normal 39C, then look for another reason why the lamb is unwell.

If the temperature is between 37C and 39C, the lamb is slightly chilled. Bring the ewe and lamb(s) into a dry, sheltered area; dry the lambs and feed 50ml colostrum /kg bodyweight. Check regularly.

If the body temperature is below 37C, the lamb is severely chilled. If the lamb is less than 5 hours old, dry it and warm it at 35 – 40C for ½ to 3 hours then feed it. If the lamb is over five hours old, dry the lamb, administer an intraperitoneal glucose injection then warm. Once body temperature has returned to normal, the lamb can be fed. If you feed a lamb that is severely chilled immediately, it may fit and die.

Glucose injection

While I can describe the process here, it is a poor substitute for hands-on instruction. If you go on a good lambing course, you will be shown how to do this procedure.

I have never had to do this for real, but I did get to try it on a lambing course using dead lambs and it wasn’t as difficult as I expected. The pile of little corpses for us to practice on was more upsetting :-(

The dose is based on lamb liveweight so weigh or estimate. You need 10ml of 20% glucose solution per kg bodyweight at 37C.

To make a 20% glucose solution, dissolve 2g of glucose powder in 10ml of freshly boiled water and allow to cool to blood temperature OR if you have bought 40% sterile glucose solution, draw half the required quantity of 40% sterile glucose solution into the syringe and dilute with the same quantity of freshly boiled water.

Use a 50ml sterile syringe and a 19g x 1” needle.

Hold the lamb between your knees so that the belly faces outwards; locate the injection site, which is 1cm to the side and 2cm below the umbilical stump i.e. towards the back legs.

Ensure that the needle enters the body at an angle of 45 degrees to the lamb’s body, pointing towards the tail.

Once the injection has been given, spray the site with antibiotic aerosol.

Recovering lambs

Lambs that recover from hypothermia need to be regularly checked to ensure that it doesn’t happen again. If there are no obvious environmental conditions, check the ewe for mastitis and consider removing a lamb, if she has twins or triplets and either fostering it to another ewe or feeding it artificially, or topping the lambs up.