The wound repair function of mare's milk and colostrum was investigated. Mare's colostrum improved wound healing in vivo; thus fibroblast growth activation by mare's milk and colostrum was examined. As expected, colostrum was more effective than milk. To establish the biochemical nature of the bioactive molecules involved, colostrum was fractionated into whey, casein, and fat globules, and the efficacy of these fractions on fibroblast proliferation was studied. The fat globule fraction provided the strongest stimulation; its composition was studied and compared with the less-active milk fat globule fraction. The lipid pattern highlighted several differences between mare's colostrum and milk; in particular, total lipid, linoleic acid, linolenic acid, ganglioside, and glycolipid contents were higher in colostrum. A proteomic investigation revealed some differences between the protein composition of colostrum and milk fat globules. Adipophylin and lactadherin were significantly overexpressed in colostrum fat globules. The role of specific lipids on skin wound repair and that of the epidermal growth factor-like domain, embedded within the lactadherin molecule and probably released in conditions stimulating proteolysis, are discussed.