Serum immunoglobulin (Ig) levels were measured in 39 consecutively newborn goat kids on an intensively managed dairy goat farm in New England using a quantitative, spectrophotometric zinc sulfate turbidity assay. The health and performance of these kids was monitored through weaning at 6–7 weeks of age. By weaning time, 24 kids were healthy, four had required treatment, and 11 had died. The mean serum Ig concentration for all kids was 1170 mg/dl. Mean serum Ig level for healthy kids was 1439 mg/dl, for treated kids, 706 mg/dl, and for dead kids, 750 mg/dl. There was a statistically significant difference in mean serum Ig levels between the group that died and the group that remained healthy ( P<0.05). No differences were observed in either death rates or mean serum Ig levels between male and female kids. Among kids that remained healthy through weaning, there was no identifiable correlation between initial serum Ig concentration and average daily weight gain. It was concluded that the failure of passive transfer of maternal antibodies to kids via colostrum at birth leads to increased morbidity and mortality from infectious disease in young goats. Results from this study suggest that in intensively managed dairy goat herds in New England (USA), failure of passive transfer in newborn kids can be defined by the presence of circulating serum Ig levels less than 1200 mg/dl.