Effect of induction of parturition on immunoglobulin content of colostrum and calf serum

Thirty-four pregnant crossbred beef cows were injected with prostaglandin F(2) alpha (PGF group, n = 11), dexamethasone (DEX group, n = 11), or saline (control group, n = 12) on Day 270 of gestation. Immediately after calving, all colostrum was milked from each cow. A sample was taken, and the remainder was fed to that cow's calf within one hour of birth. Serum was collected from each calf at 0 and 24 h of age. Immunoglobulin G (IgG) content of colostrum and serum was determined with commercial radial immunodiffusion plates. The data from four PGF cows that did not calve until after 140 h post injection were excluded from the results. Mean (+/- SD) volumes (ml) of colostrum were 2086 (+/-1148.4) for the PGF group, 1336 (+/-583.7) for the DEX group, and 2404 (+/-1140.7) for the control group. Mean (+/- SD) concentrations (mg/dl) of IgG in colostrum were 6017 (+/-3351.2) for PGF, 10285 (+/-5370.7) for DEX and 10766 (+/-5098.3) for the control group. Mean (+/- SD) total quantities of IgG (g) in colostrum were 133.9 (+/-120.03) for PGF, 134.1 (+/-96.67) for DEX and 235.6 (+/-147.22) for the control. IgG concentrations were very low or were not detectable in serum of all calves prior to administration of colostrum. Mean (+/- SD) concentrations (mg/dl) of IgG in serum of calves at 24 h of age were 1469 (+/-905.8) for calves from PGF cows, 1819 (+/-1289.8) for calves from DEX cows, and 3317 (+/-1888.2) for calves from control cows. Calves from control cows had significantly more IgG at 24 h than calves from PGF cows or DEX cows (p<0.05). Calves born to cows induced to calve early may be at an increased risk of failure of passive transfer and so should be monitored for IgG concentrations.