Abstract
The mean concentrations of total serum protein, γ-globulin and antibody were almost identical in groups of Finnish Landrace lambs from litters in which one, two or three, respectively, survived till the 3rd day. Lambs from two litters each with four survivors had considerably lower mean concentrations. Merino × Cheviot and Scottish Blackface lambs examined previously had significantly lower serum protein concentrations than the Finnish lambs and higher antibody levels in single than in twin lambs.