Understanding lamb losses

Understanding where lamb losses are occurring is very valuable information and, when utilised, can help improve future lamb survival.

From scanning to tailing it is normal to see losses, but if you are seeing losses greater than 15% then there is room for improvement and an opportunity to increase efficiency.

Losses tend to fall into four main categories:

  1. Starvation/exposure
  2. Dystocia
  3. Infection
  4. Iodine Deficiency

A basic post-mortem can be performed on farm by a farmer to help identify how a lamb has died.

The first step is to weigh the lamb – twins will be smaller, but even these should be at least 4kg. Then, give the lamb a general check over – are there any obvious abnormalities? Has the lamb walked? There are soft membranes, known as ‘slippers’, that cover the feet of lambs. When they walk, these ‘slippers’ disappear and a normal hoof is present. This rules out dystocia.

To perform the post mortem, an incision is made from under the front leg and up through the neck to the head. Check this area for any swelling or ‘jelly-like’ material known as oedema. Any possible swelling around the head and neck indicates dystocia as the cause of death, because these areas will swell when the lamb gets stuck.

The thyroid gland is a butterfly-shaped gland that sits in front of the trachea (windpipe). In order to determine if iodine deficiency is the cause of death, this gland needs to be weighed very accurately at a vet clinic. An enlarged thyroid gland (thyroid to bodyweight ratio greater than 0.4) can mean that the lamb likely had iodine deficiency. Ideally the thyroids of at least 10 lambs, along with their bodyweights, are needed to create a representative sample.

Next, open the chest. If the lungs are pink and soft the lamb has breathed. A good way to check is to cut a small piece of lung out and put it in water. It will float if it has breathed.

Open the abdomen and check over both the heart and kidneys. If the lamb has a dark red-to-brown fat covering these organs, it is likely that the lamb has tried to mobilise its body fat, run out of energy and died of starvation/exposure.

Check the contents of the stomach to see if the lamb has managed to feed. An empty stomach could indicate mis mothering or mastitis in the ewe.

Finally, check for any signs of infection. These could include a large volume of fluid in the abdomen and/or an abscess in the liver, chest or around the navel.

If you would like to take the dead lambs to a Vetlife Clinic for post mortem, then fresh is best. Do not freeze any lambs as the freezing can interfere with any samples that may need to be taken, however you can chill them. If you can get some or all of the placenta of each dead lamb, then bring that in as well.