Failure of Passive Transfer

Risk Factors and Effects on Lifetime Performance

Abstract

Blood samples were collected from the first calves of 48 four-breed composite cows and postpartum hours 0 and 24 (group 1) and heparinized blood samples were collected from the 263 calves born to 203 cows at postpartum hours 10 (±2) and 24 (±2) (group 2). For group 1, at birth, the mean serum concentrations of IgG and protein were 131 mg/di and 3.9 g/dl, respectively, and serum activity of GGT was 28 IU/L. After 24 hours, these values had increased to 1,400 mg/di, 5.0 g/dl, and 734 IU/L, respectively. The calves with failure of passive transfer (FPT) had a 9.5 times greater risk of becoming classified as sick prior to weaning compared with calves with partial FPT and normal passive transfer <£=0.0004). The retrospective sensitivity and specificity of a cut-off value of 200 IU of GGT/L of serum for diagnosing FPT were 80 and 97%, respectively. The retrospective sensitivity and specificity of a cutoff value of 4.2 g of protein/di of serum for diagnosing FPT were 80 and 100%, respectively. The Kappa values for diagnosis of FPT using serum concentrations of lgG vs serum activity of GGT, IgG vs protein, and GGT vs protein were 0. 72, 0.86, and 0. 79, respectively. For group 2, the prospective sensitivity and specificity of a cut-off value of 4.8 g of protein/di of plasma, measured at 10 hours, for diagnosing FPT at 10 hours were 78 and 94%, and for diagnosing FPT at 24 hours were 88 and 73%, respectively. Colostrum supplement administered to calves with low PP concentration at 10 hours had no effect on PP or IgG values at 24 hours or on preweaning morbidity and mortality. Total PP and IgG concentrations were similar for single and twin calves at 10 hours, but IgG values at 24 hours were higher (£ < 0.01) in twin calves. Calves born to dams that had dystocia had consistently lower mean PP and lgG values. However, observed differences were small, and after adjustment for other important factors, these differences were not significant. Calves of dams diagnosed with mastitis had lower mean PP and IgG values at 10 (£ < 0.05) and 24 (£ < 0.01) hours. Results of logistic regression analysis indicated that IgG concentration at 24 hours was associated with morbidity and mortality outcomes prior to weaning. Calves classified as having inadequate IgG concentration at 24 hours were at greater risk of mortality from birth to weaning (odds ratio [OR]= 5.4), morbidity in the first 28 days of life (OR= 6.4), and morbidity from birth to weaning (OR = 3.2), compared with calves classified as having adequate IgG concentration at 24 hours. Calves classified as having marginal IgG concentration at 24 hours also had a greater risk of preweaning morbidity (OR= 3.6), compared with calves that had adequate IgG concentration. Calf PP concentration at 24 hours was associated with morbidity in the feedlot. Calves classified as having inadequate PP concentration were at greater risk of feedlot morbidity (OR= 3.0) and feedlot respiratory tract morbidity (OR= 3.1). The lowest calf weaning weights were observed among calves classified as having inadequate lgG or PP concentration at 24 hours. However, multivariable modeling indicated that the effect of passive transfer on weaning weight was indirect through its effect on neonatal morbidity. Morbidity during the first 28 days of life resulted in a 16-kg lower expected weaning weight. Similar to weaning weight, passive immune status at 24 hours was not directly associated with feedlot growth rate. There was, however, an indirect association through the effect of PP concentration at 24 hours on morbidity in the feedlot. Adjusted mean MDG for calves with respiratory tract morbidity while in the feedlot was 0.04 kg less than that for noncases. The magnitude of the effects of passive immune status on the health and growth performance of calves in this study emphasize the importance of producer management strategies to identify calves at risk of failing to acquire passive immunity and to provide appropriate intervention.