what area of the country do you live. cause in certain areas a lack of selenium in the soil and therefore mothers milk can lead to "white muscle disease".
We give our newborns a vitamin B and some selenium as a preventative and weve never had it for 20 years . (We used to get white muscle diosease all the time with newborn lambs)
We live in the eastern US where the Se/Mo is deficient.
Get a Se vitamin supplement and give it by IM shots.