Chitotriosidase is a functional chitinase with a high homology to chitinases that belong to family 18 of glycosyl hydrolases. Although research on chitotriosidase has been undertaken in humans (Musumeci et al., 2005) and goats (Argüello et al., 2008; Hernández-Castellano et al., 2011; Moreno-Indias et al., 2012b), this enzyme has never been described in sheep or lambs.