Probiotics are becoming increasingly advocated as being of benefit to calf rearers as a feed additive to improve the growth rates and health of rearing calves. There are several organisms and mixtures of organisms that are now commercially available which may prove to be a realistic alternative to the widespread use of antibiotic growth promoters. There is a lack of published work by independent researchers on the efficacy of probiotics for rearing calves but a wealth of manufacturers literature. Two experiments at Drayton E.H.F. investigated the use of Enterococcus faecium as a probiotic agent during the rearing period of purchased calves.