Passive transfer of colostral immunoglobulins from ewe to lamb and its influence on neonatal lamb mortality

The transfer of immunoglobulin G (IgG) and immunoglobulin M (IgM) from ewe to lamb was quantitated to determine the occurrence of failure in passive transfer. Concentrations of IgG and IgM in ewe serum did not correlate with those in the colostrum. Colostrum from all ewes contained abundant amounts of immunoglobulins when compared with serum values, with IgG being selectively concentrated over IgM. Absorption through the intestinal tract of the lamb appeared to be a nonselective process, lacking predilection for IgG and IgM. All lambs tested 24 hours after birth absorbed colostral immunoglobulins to some extent; however, 13 (14%) of 91 clinically normal lambs demonstrated some failure of passive transfer. In contrast, failure of passive transfer was found in 27 (46%) of 59 lambs dying of natural causes between 24 hours and 5 weeks of age. Evidence presented emphasizes the importance of absorption of adequate amounts of immunoglobulins to enable the newborn lamb to survive the first few weeks of life.