Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your wee one’s situation, and wanted to help.
Again I do apologize that my colleagues could not aid you sooner, but can you tell me:
How many affected lambs have you had? How long ago did the most recent one die?
How long after the lameness are the lambs dying?
What is your vaccine program? What do you use?
Any access to toxins (ie heavy metals, chemicals, etc) or any chance of trauma/injury?
Did the lamb have pale gums, fever, or breathing changes?
Was it on mum or being bottle fed?