Serum lactoferrin concentrations in colostrum-fed calves

Abstract

Objective - To determine serum lactoferrin concentrations (SLFC) in neonatal calves before and after ingestion of colostrum and to develop models that predict SLFC as a function of colostral lactoferrin concentrations (CLFC) in calves. Animals - 13 Holstein calves. Procedure - Calves were fed 4 L of colostrum via oroesophageal feeder within 3 hours after birth. Serum samples were collected before ingestion of colostrum (day 0) and 2, 4, 6, and 7 days after birth. Colostrum and serum IgG concentrations were measured by use of radial immunodiffusion. The CLFC and SLFC were determined by use of an ELISA. Results - Mean ± SD SLFC on days 0, 2, 4, 6, and 7 were 2.5 ± 1.6 (range 0.47 to 7.1), 6.0 ± 3.0 (range 2.0 to 16.6), 12.0 ± 12.4 (range 0.0 to 43.5), 17.1 ± 13.6 (range 2.2 to 39.4), and 13.6 ± 16.4 (range 0.0 to 43.8) mg/ml, respectively. The SLFC on days 6 and 7 differed significantly from SLFC on day 0. The model that best estimated SLFC on day 6 predicted that (SLFC)2 was a function of the logarithm of relative efficiency of passive transfer (REPT) and ([CLFC]2 × [REPT]2), where R2 = 0.4. The model for SLFC on day 7 predicted that (SLFC)2 was a function of log(REPT), where R2 = 0.44. Conclusions and Clinical Relevance - Definitive evidence for passive transfer of lactoferrin via colostrum is lacking, because SLFC on day 2 or 4 were not significantly different than day 0. Relative efficiency of lactoferrin absorption was directly related to SLFC on day 6 but inversely related to SLFC on day 7.