Passive transfer of colostral immunoglobulins in calves

Passive transfer of colostral immunoglobulins has long been accepted as imp erative to optimal calf health. Many factors, including timing of colostrum ingestion, the method and volume of colostrum administration, the immunogl obulin concentration of the colostrum ingested, and the age of the dam have been implicated in affecting the optimization of absorption. The practice of colostrum pooling, the breed and presence of the dam, and the presence o f respiratory acidosis in the calf also may affect passive transfer. Variou s tests have been reported to accurately measure passive transfer status in neonatal calves. The radial immunodiffusion and the enzyme-linked immunoso rbent assay (ELISA) are the only tests that directly measure serum IgG conc entration. All other available tests including serum total solids by refrac tometry, sodium sulfite turbidity test, zinc sulfate turbidity test, serum gamma -glutamyl transferase activity, and whole blood glutaraldehyde gelati on estimate serum IgG concentration based on concentration of total globuli ns or other proteins whose passive transfer is statistically associated wit h that of IgG. This paper presents a comprehensive review of the literature of passive transfer in calves including factors that affect passive transf er status, testing modalities, effects of failure of passive transfer on ba seline mortality, consequences of failure of passive transfer, and some tre atment options. Many previously accepted truisms regarding passive transfer in calves should be rejected based on the results of recent research.