I'm going to start this post by quoting from Eddie Stratons sheep book. Sorry I don't know the title of the book. Becky sent me this quote in an email two years ago.
"Daft Lamb Disease:
Like swayback, daft lamb disease is a condition of new born lambs and is the only disease know which is likely to be mistaken for swayback: in fact the two conditions are sometimes indistinguishable.
Fortunately, however, daft lamb disease is uncommon and is seldom, if ever, a major problem. It is chiefly in the Border Leicester breed and its crosses, e.g. the Scottish halfbred and the Greyface.
Daft lamb disease is not due to a mineral deficiency but is genetic in origin. Part of the lamb's brain the cerebellum is congenitally atrophied (imperfectly developed).
Most cases have a characteristic jerking backwards of the head. They carry the head high and have the mouth pointing backwards or towards the side. In the more severe cases the lambs are blind and walk in circles. Despite this the appetite remains good.
There is none, though mild cases can be hand reared and given a chance. Most cases are destroyed by shepherds or die of exposure or starvation. Those that can walk may improve gradually, and some may become apparently normal except when excited.
Cull the mothers and change the tub (ram). One obvious preventative measure is to avoid buying rams from flocks where the condition is know to exist." end quote.
Kess's ewe lamb born the morning of April 12, 2010 and below is Sisken and her two lambs born the same day from the same ram. Siskens two lambs are both doing great. Sisken has always had healthy lambs and I do not consider her a carrier because of this. She has been bred, in my experience, to both carrier and non carrier rams.
Kess was considered by me to be suspect since her full sister Bella had the two blind lambs '08. Kess had a normal ewe lamb last year and this ewe lamb of hers is blind. Oma bred to the same ram was to me a carrier, she had twins in '08, one blind and died the other healthy. She had two healthy lambs last year. This year when Oma was bred to the same ram as Kess, she had twins again one was blind and died, her ram lamb is doing well.
So far this year one ram has had four ewes lamb. Two carriers and two non carriers, like I say this is my opinion, both carriers had blind lambs and both non-carriers have healthy lambs. Two more ewes bred to this ram have not lambed yet. One Yeesha I believe is a non-carrier, from a ewe and ram who's genetics do not link to daft lamb in my flock and Hazel, suspect because her sire was one of the original rams to plant this seed of daft lamb in my flock. Hazel is a two year old and this is her first lambing. She will have a one in four chance of carrying the gene.
My other ram has had two ewes lamb one Bella a carrier and Hattie who could carry the gene both have healthy twin lambs.
This is an ongoing study and bless you Laura Cunningham for getting in touch with Phillip Sponenberg DVM PhD who has encouraged me to compile all my records of affected lambs. God bless blogs who got me, a fairly lame record keeper to document my lambings since 2008.
I was ready to just cull all animals who I have, that have had trouble with this and hide these lambs from everyone. Instead I find this very distressing since it has been talked about in the Shetland sheep for more years than I have been breeding Shetlands and I find more "hide it under the rug" people than ones who wish we had a way of testing our sheep to rid the Shetlands of this problem. My Opinion
P.S. these sheep have been followed by vets and had necropsies and blood tests done from the West coast to the East coast where all the common viruses, bacterias etc have been ruled out. And if it were one of these why does this happen to only Shetlands and only some family lines of Shetlands. My sheep are proof of that.