Thursday, January 31, 2013

Chilled Lamb/Hypothermia Management


The normal temperature of a lamb is 39-40°C 102-104°F.The main causes of hypothermia is exposure and starvation.

Lambs suffering from starvation hypothermia will have a low blood glucose level.If this glucose level is not corrected before the lamb is warmed up it is likely that the lamb will die from a fit during warming up.

It is more common for a lamb to die from hypothermia than disease.
Lambs are usually born during the coldest months of the year.If the lamb cannot maintain the correct body temperature it can lead to death.
Many of these deaths can be avoided by good farm management.
A smaller lamb will chill faster than a larger lamb. Some lambs are born with thicker coats than others these seem to be able to ward of the cold more than the thinner coated lambs.


The risk of hypothermia is also increased if a lamb is a twin or triplet or from an inexperienced sheep. The quicker a lamb is licked dry by the mother the less likely it is to get chilled.

If a lamb is born in a secure draft free environment it has more of a chance of survival.If the lamb has no shelter with the cold wind its heat loss will be accelerated.The lambing shed needs to be draft free with good ventilation.


Being in the lambing shed you can watch to see if the lambs are being licked and getting their first feed of colostrum from the ewe.




The best way to recognize hypothermia is to take the rectal temperature of the lamb. The chilled lamb will be weak dull and not willing to suckle. The quicker the lamb gets treatment the better the rate of survival
The lower the temperature the sicker the lamb.
The normal rectal temperature of the newborn lamb is 39  to 40°




Treatment

When a lamb is suffering from hypothermia you want to warm it up and provide nourishment for energy.

Mild Hypothermia

The lambs rectal temperature is between 37 and 39 °C with mild hypothermia.
The lamb will be weak but may be still able to stand.Move the lamb to draft free shelter and stomach tube feed it colostrum.Give the lamb a good rub with a towel and put it in a pen with a heat lamp.
Extra small lambs may not have enough fat reserves to start heat production even with colostrum.They can be fed 20% dextrose solution by stomach tube.

Severe Hypothermia

When the rectal temperature is below 37° more urgent treatment is requirement.
The lamb must not be given colostrum until it is revived.The temperature must be brought above 37°C.

Reversing the hypoglycemia must be done first and then warm the lamb up slowly in a warming box.
A 20%  dextrose solution at a dose rate of 10ml/kg body weight is injected into the abdominal cavity.Known as intra peritoneal injection.
Ask your vet to show you how this.The site of the injection is about 2cm below the navel and 2cm lateral to the midline.Use a large 60mm syringe and a 20 or smaller gauge 1 inch needle.Inserted at a 90 degree angle to the body wall.
 
The lamb needs to be slowly warmed.You should use a warming box.
A warming box is a container heated by warm moving air at 39 to 40 degrees Celsius. Use the warm air heater rather than the heat lamp at this point of time.Keep a check on the rectal temperature once the temperature has reached 37°C the lamb can be given colostrum via stomach tube.Returned to the mother in a warm draft free area when it is able to nurse unaided. Until it is able to suckle of ewe unaided keep it in a pen with a heat lamp.
 
 
Remember if the lamb can swallow feed the lamb via stomach tube the colostrum if it cannot swallow give it the 20% dextrose solution via intra peritoneal injection get your vet to show you how.



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