Absorption of Colostral Immunoglobulin G in the Newborn Dairy Calf

Abstract

Five groups of 8 newborn calves were used to study absorption of colostral IgG. One feeding of 2 l of pooled colostrum was given at 6, 12, 24, 36 or 48 h after birth. Concentrations of IgG in blood plasma and feces were measured by an immunodiffusion technique. Plasma volume and fecal excretion also were measured. When colostrum was given 6 h after birth, 65.8% of the ingested IgG appeared in the plasma. This percentage declined rapidly to reach 46.9, 11.5, 6.7 and 6.0% when colostrum was given at the ages of 12, 24, 36 and 48 h, respectively. Total fecal IgG increased linearly with age. The quantities not recovered from plasma and feces reached a maximum when colostrum was given at 24 or 36 h after birth. IgG can be lost to a great extent via routes other than plasma and feces during this time. Quantities of IgG measured in plasma represent apparent rather than true absorption. [The dairy calf is born with insufficient immunity to resist infection in its new environment. Passive immunity is acquired through colostral Ig.].