The invention relates to the production of proteins and other substances of interest in saliva of transgenic animals, particularly in mammals that produce large quantities of saliva, particularly monogastric ruminants, and ovine, caprine and bovine mammals. Preferred embodiments of the invention relate in particular to the production of foreign and modified proteins in the transgenic saliva of these animals, including particularly human fibrinogen, human prothrombin and human thrombin, among others. The invention relates as well to methods, devices, genetic constructs and to transgenic constructs for making the proteins and other substances of interest, to novel saliva and saliva-derived compositions, novel products from the saliva, and to uses of the saliva, saliva-derived compositions and novel products.