Abstract
Levels of the immunoglobulins IgG and IgG(T) in serum in Norwegian horses of the breeds “Døle” and “Fjord” were determined by the quantitative radial immunodiffusion test. No significant differences were apparent between the 2 Norwegian breeds. The immunoglobulin levels were approximately in the same range as previously reported for Shetland ponies. Immunoglobulins could not be detected in the newborn foal. As early as 24 hrs. after birth the mean immunoglobulin level was within the adult range. After a drop during the first month of life, the immunoglobulins increased. IgG(T) rose more rapidly and to a higher level than IgG. In 2 year old horses, IgG(T) was significantly higher than in adults, while IgG was significantly lower. IgG(T) seems to be a very important immunoglobulin in foals and young horses.