With tupping fast approaching, Hairy Shaker Disease (HSD) is something to think about.
HSD, or Border disease, is a form of pestivirus in sheep, very similar to Bovine Viral Diarrhoea (BVD) in cattle. It is often the cause of poor scanning rates, barren ewes, abortions, stillbirths, and the birth of weak lambs.
This highly contagious disease can be spread from ewe to lamb via the placenta or milk, from ram to ewe during mating, and between ewes via nose-to-nose contact.
Ewes that are infected will not show any clinical signs. The effect of HSD depends on when they are infected:
Healthy, mature dry sheep – very mild disease, often going unnoticed.
Ewe in late pregnancy (i.e. more than 85 days) – lamb born normally with antibodies to the virus.
Ewe in early pregnancy (i.e. less than 85 days) – abortion or live ‘hairy shaker’ lamb.
A hairy shaker lamb is often small and underdeveloped and will have a coarse shaggy coat, tremor involuntarily, and be weak or uncoordinated. These lambs have a very poor survival rate, with most dying shortly after birth. Those that survive are ‘persistently infected’ with the virus, which means they will continue to shed the virus, and infect other animals, for the rest of their life.
Unfortunately, there is no treatment or vaccination available in New Zealand for HSD. So, if an outbreak occurs:
Cull all lambs showing hairy shaker characteristics.
Implement testing of introduced stock to identify if any are ‘persistently infected’ animals.
Cull ewes that produce hairy shaker lambs in two consecutive years.
Maintaining a closed flock is the best way to prevent the disease, as ewes that are bought-in pose the greatest risk. If you need to bring ewes in, they should ideally be quarantined and tested, joined separately, and kept apart from the main flock until lambing.
