BLOOD-DERIVED IMMUNOGLOBULINS IN MILK REPLACER, OR BY INJECTION, FOR IMPROVED PERFORMANCE OF COLOSTRUM-DEPRIVED NEONATAL CALVES

Two experiments involving a total of 60 colostrum-deprived neonatal calves were carried out with the objective of demonstrating the efficacy of supplementing colostrum-deprived calves with Ig isolated from bovine blood. The first experiment consisted of four treatments: Col-WM, colostrum on Day 1 and whole milk for Days 2-42; MR-NoIg, unfortified milk replacer for Days 1-42; MR-Hi-LoIg, milk replacer with a high level of Ig (50 mg ml-1) on Day 1, a low level of Ig (10 mg ml-1) on Days 2-21 and unsupplemented milk replacer on Days 22-42; MR-Hi-NoIg, milk replacer with a high level of Ig (50 mg ml-1) on Day 1 and milk replacer with no Ig on Days 2-42. The scour index was significantly higher (P<0.05) for MR-NoIg calves than for those fed Col-WM. Average rate of gain and feed efficiency for MR-NoIg calves were significantly lower (P<0.05) for Days 1-42 compared with the other three groups of calves. The serum Ig concentrations were significantly higher (P<0.05) for the Col-WM group than the other three groups during the first week of the experiment. The MR-Hi-NoIg calves showed an initial response in serum Ig levels but these concentrations remained low throughout the trial, whereas the serum Ig concentrations of the MR-NoIg calves gradually increased and were equivalent to those for the Col-WM calves by the end of the trial. In the second experiment, 24 colostrum-deprived calves were randomly assigned to one of the following treatments: Col-WM, colostrum on Day 1 and whole milk on Days 2-2 1; Inj-MR-LoIg, injection of Ig on Day 1, milk replacer containing a low level of Ig (10 mg ml-1) for Days 2-21 and milk replacer without Ig for Days 22-42; MR-Nolg, milk replacer without Ig for Days 1-42. The scour index was significantly higher (P< 0.05) for the MR-Nolg calves than for the other three groups. Average rate of gain for Days 1-42 was 0.66 kg day-1, 0.55 kg day-1 and 0.35 kg day-1 for the Col-WM, Inj-MR-LoIg and MR-NoIg groups, respectively. It was concluded from the results of these two studies that the injection of Ig or the supplementation of milk replacer with Ig isolated from abattoir blood was effective in increasing serum Ig levels in colostrum-deprived calves, but not to the concentrations achieved by feeding colostrum.