Investigating Neonatal Losses: On-farm Postmortem

_{Postmortems are a valuable tool for understanding neonatal lamb losses.}

Lamb losses in the neonatal period can have a profound impact upon that year’s reproduction figures, as well as the wellbeing of farmers. The term ‘neonatal’ loss can be used to cover death in lambs from birth to approximately two-weeks-old. The target for losses in this period should be less than five per cent, so investigate when losses exceed this figure, or before if a farmer is willing to do so. Postmortem of affected lambs can yield useful results and can be carried out at one of SRUC’s disease surveillance centres, or on farm.

Below are some considerations for if you are carrying out on farm postmortems:

Establish at what age lambs are dying:

• Was the lamb born alive or dead? Do the lungs float in water? If so, the lamb has breathed and has died after birth
• Is the navel dry? If so, the lamb is likely more than 12 hours old

Look for evidence of dystocia/trauma:

• E.g. fractured ribs, liver rupture, peripheral oedema, brain haemorrhage

Inspect the umbilicus to look for evidence of infection:

• Such cases may present as peritonitis or hepatic necrobacillosis
• Navel infections can be the root of polyarthritis and meningitis at a later stage

Has the brown fat been mobilised?

• This will give an idea as to how long after birth the lamb died
• Check around the kidneys, the mesentery and the epicardial groove

Incise into the abomasum:

• Has the lamb sucked? Milk clots and milk should be present in a well-fed lamb
• Is there evidence of watery mouth?
• Look for distension of abomasum with gas and profuse watery content. E. coli can be isolated from abomasum and small intestine

Check if the anus is patent

If you are undertaking a postmortem on farm, please feel free to get in touch for further advice on sampling, etc.

Posted by Veterinary services on 12/04/2021