Short communication: Effect of feeding pooled and nonpooled high-quality colostrum on passive transfer of immunity, morbidity, and mortality in dairy calves

摘要

Pooling colostrum is commonly practiced on Irishdairy farms. Pooling can result in dilution when colostrumswith high and low IgG concentrations aremixed, thereby predisposing calves to failure of passiveimmunity. The objectives of this study were to compareIgG concentrations in colostrum from individual cowswith colostrum pooled from several cows, and assessserum IgG concentrations, morbidity, and mortalityamong calves fed colostrum from their own dam, froma different cow, or pooled from several cows. We hypothesizedthat pooling colostrum reduces IgG concentrationdue to dilution compared with colostrum fromindividual cows, and that calves fed pooled colostrumachieve lower serum IgG concentrations than calves fedcolostrum from individual cows. Calves were randomlyassigned to 1 of 3 groups: (1) fed colostrum from theirown dam (n = 20); (2) fed colostrum from a differentdam (n = 20); or (3) fed pooled colostrum (n = 18).A sample of colostrum fed to each calf was collected.Serum samples were collected from calves at birth (0h) and at 24 h after colostrum feeding. Colostrum andserum IgG concentrations were measured by radialimmunodiffusion. Calves were weighed at birth and atweaning, and the health status of each calf was assessedtwice daily. Health assessment was based on generaldemeanor, rectal temperature, fecal consistency, respiratoryrate, and the presence of cough, nasal, or oculardischarge. Colostrum and serum IgG concentrations,and weaning weights were compared using ANOVA.Associations between group and morbidity or mortalityrates were compared using χ~2 or Fisher’s exact tests.Median and 95% confidence intervals (95% CI) of IgGconcentrations of colostrum were 99.4 (81.8–111.5),95.2 (84.1–107.2), and 100.7 (90.5–104.4) g/L for owndam, different dam, and pooled groups, respectively.We did not find any differences in colostrum IgG concentrationsamong the colostrum sources. Median(95% CI) serum IgG concentrations at 24 h were 52.0(45.6–65.9), 55.7 (51.2–65.9), and 53.1 (46.2–63.7) g/Lfor calves that received colostrum from own dam, differentdam, and pooled, respectively. All calves achievedadequate passive immunity. Serum IgG concentrationsat 24 h, weaning weights, and proportions of morbidityand mortality were not different among the 3 groups.Our results suggest that on dairy farms where mediancolostrum IgG concentrations are high and colostrummanagement is optimal, pooling has a minimal effecton passive immunity and subsequent calf health.