Anotace:
Different trials demonstrated lactoferrin (LF) to possess antimicrobial, antiviral, antimycotic and anti-inflammatory activity. This molecule is an iron-binding protein that could have preventive effects on calf diseases. Several authors studied the effects of LF at doses between 1 and 10 g/calf/day as a supplement in milk administrated to weaning calves. The results are variable and not always consistent. Twenty-two female replacement calves divided into 2 groups (Control-C and Treated-LF) during a 56-d experimental period were employed to investigate the effect of the use of 0.1 g/d of LF during weaning on growth performances, feed efficiency and health status. The field trial was conducted employing an early weaning protocol (49-d of length, excluding the colostral phase). After parturition, density and immunoglobulin G (IgG) content of dam colostrum were measured as a colostrum quality indicator. Only colostrum with at least 50 mg/mL of IgG was bottle-fed to the calf. Morphometric measurements and feedstuff intake were recorded weekly. Health status and milk consumption were evaluated daily. Calves receiving low doses of LF had numerically less incidence of diarrhoea than the C group (P > 0.05). From a statistical point of view, any significant difference was observed between groups both on growth performances and feed efficiency. A trend for an increase of the FCR was found for LF group at weaning (P = 0.099). More researches are needed to define the optimal dose and the real action of LF in weaning calves.