The Collaborative International Dictionary of English v.0.48:

Lactoabumin \Lac`to*a*bu"min\, n. [L. lac, lactis, milk + E.
   albumin.] (Physiol. Chem.)
   The albumin present in milk, apparently identical with
   ordinary serum albumin. It is distinct from the casein of
   milk.
   [1913 Webster]