Dystocia (difficulty in lambing)
Difficult birth can be caused by the lamb being too large for the ewe’s birth canal. This can be avoided by ensuring ewes are correct size and body condition, as well as selecting rams with an ASBV for smaller lambs, especially for maiden ewe flocks. Other causes include malpresentation e.g. head or leg back, or tail presented to birth canal, or ewe weakness, or over nutrition of ewes in late pregnancy.
Force should not be used to deliver lambs (alive or dead) due to the danger of injury to the ewe and lamb. Instead, lubrication, manipulation and adjusting the presentation so that the lamb’s head and feet (if head first) or two hind feet (if tail first) are together as they exit the birth canal.
Tell-tale signs of birth trauma include large-headed lambs, no evidence of walking or breathing, subcutaneous oedema, empty stomach and haemorrhage of the liver, or of the brain or spinal cord.
Apart from lamb deaths, dystocia also accounts for a large proportion of ewe deaths. Ewes that are given assistance at birth should be clearly marked, and the lamb also identified for later culling. This is because ewes will often go on to have birth difficulties in subsequent years, and lambs from these ewes may also not be good breeders.
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