Border Disease (BD) in sheep is most often seen as the " Hairy-Shaker" lamb, which is a newborn lamb with a hairy coat and trembles uncontrollably. It is caused by a virus and causes a wide variety of symptoms depending upon the stage of pregnancy when the ewe becomes infected. It is usually brought into a flock by new additions that are carriers or when sheep are commingled with cattle that are shedding the Bovine Viral Disease Virus (BVDV). Sheep affected with Border Disease are characterized by open ewes, abortions, weak and frail lambs, abnormal hairy coat, nervous symptoms that cause the lamb to shake. Recently I have had several calls from producers that have described this disease in their flocks, I recommend that they confirm the diagnosis by having their veterinarian draw blood from the affected ewes and sending in several of the diseased lambs to a diagnostic laboratory.
In affected ewes the most common clinical symptom is abortion of macerated or mummified lambs. If a mature sheep is exposed to the BD Virus it will shed the virus for only a short period of time. However, any lamb that is affected in the first 70 to 90 days of pregnancy while in their mothers uterus it will shed the BD Virus for an entire lifetime and be a threat to the flock’s health. Lambs that are born with the nervous tremors will outgrow the shaking at about 16-20 weeks of age, but still will most likely be shedders of the virus.
If you suspect that you have Border Disease Virus in your flock you need to consult with your veterinarian and do the necessary diagnostic test and develop an entire plan for removal and clean up of the flock. These sheep do not respond to any treatment with antibiotics. The threat of chronic infections that are actively shedding the virus for a lifetime makes this a disease that can devastate a flock.
J.D. Bobb, DVM
International SheepLetter
Vol. 19 No. 7, January 2000