Longitudinal Analysis of Serum Immunoglobulin Transfer Efficiency and Passive Immunity Adequacy in Neonatal Calves at Beef Farms in Niger State, North Central Nigeria

Failure of passive transfer of maternal immunoglobulins is a major cause of neonatal calf mortality and morbidity in cattle production systems, yet longitudinal data on passive immunity adequacy in Nigerian beef calves are sparse. This study conducted a longitudinal analysis of serum immunoglobulin G transfer efficiency and passive immunity adequacy in neonatal calves at beef farms in Niger State, North Central Nigeria. One hundred neonatal calves were monitored from birth through seventy-two hours, with blood samples collected at twelve, twenty-four, forty-eight, and seventy-two hours post-birth for serum immunoglobulin G quantification by radial immunodiffusion, total protein by refractometry, and gamma-globulin fraction by protein electrophoresis. Dam colostrum was sampled at first milking for Brix refractometry score. Failure of passive transfer, defined as serum immunoglobulin G below 10 g/L at twenty-four hours, was identified in 34% of calves. Serum total protein below 5.5 g/dL at twenty-four hours predicted failure of passive transfer with 81% sensitivity. Colostrum Brix scores above 22% were positively associated with adequate passive transfer. Time to first colostrum ingestion was the most significant predictor of transfer adequacy in logistic regression, with delays beyond six hours increasing failure risk by threefold. These longitudinal findings provide an empirical basis for colostrum management guidelines at North Central Nigerian beef enterprises and support the adoption of colostrum quality monitoring by Brix refractometry. Keywords: passive transfer, immunoglobulin G, neonatal calves, colostrum, Niger State.