Serum IgG concentration after intravenous plasma transfusion in colostrum-deprived dairy calves

Plasma transfusion has been empirically employed in the management of newborn calves with failure of passive transfer (FPT i.e. serum IgG concentration <10 g/L) [1]. Nevertheless, the effect of an IV transfusion of plasma on serum IgG concentration in FPT calves needs to be evaluated systematically. The aim of this study is to evaluate the effect of the administration of an adequate dose of IgG in colostrum-deprived calves on their serum IgG concentration Twenty-eight Italian Friesian newborn calves, belonging to a single dairy herd, were randomly assigned to Colostrum Group (CG, n=14) or Plasma Group (PG, n=14). CG calves received 4 L of high quality bovine colostrum (> 21 of the 0:32 Brix refractometry scale) within 12 hours after birth [2]. PG calves received a dose of IgG from pooled plasma within 6 hours after birth. The IgG dose needed to obtain the minimum IgG serum level of 10 g/L in our calves has been determined by the following formula [3]: [(body weight x % blood volume) x (pretreatment serum IgG) + (Total IgG transfused)]/ (body weight x % blood volume) Plasma was collected from 20 healthy IBR free cows vaccinated against rotavirus, coronavirus and E. coli, selected from animals of the same herd with a high γ-globulin rate. To obtain plasma, 4L of blood have been collected from each cow into sodium citrate transfusion packs and subsequently centrifuged. Plasma obtained was tested for IgG concentration by ELISA and than stored at -20 °C until transfused. Serum IgG concentration before (T0) and after plasma transfusion or colostrum administration (1 day - T1, 3 days - T2, 7 days - T3) were determined by ELISA. Both groups were monitored by a daily clinical examination for a period of 3 week PG calves received a quantity of 52 ± 4,40 g of IgG in a volume of 2,23 ± 0,38 L of plasma. Four PG calves died for neonatal diarrhea complicated by E. coli septicemia at respectively 5, 11, 12, 16 days of age. On the other hand, none of the CG calves showed signs of disease or died during the study. Serum IgG concentration increased in both CG and PG calves. Mean concentration of IgG in all observation times, was higher in CG calves than PG calves (Fig.1). Altough all CG and PG calves showed an IgG value > 10g/L, the means between groups were statistically different at each observation (P<0.01) These results suggest that IV infusion of IgG is not a valid alternative to the administration of a good-quality colostrum, although both groups of animals reached an adequate quantity of serum IgG. Nevertheless, plasma trasfusion could represent an effective supportive therapy for FPT.