Experimental atherosclerosis in the young bovine

Eight male and 8 female calves were fed various diets for 24 weeks, starting at 4 days of age. Addition of cholesterol to a diet composed principally of whole milk and fed by nipple caused a marked increase in plasma cholesterol; similar supplementation of a relatively low-fat diet composed primarily of grain had no appreciable effect. Cholesterol storage in the liver was higher in calves fed milk and cholesterol than in those fed grain and cholesterol. Gross aortic sudanophilia was extensive in calves fed milk and cholesterol, less in those fed milk with no supplemental cholesterol and virtually absent in those fed a limited-milk and grain diet either with or without cholesterol. Aortic lipid was confined to the intima, and cholesterol was coextensive with the lipid. Vascular alterations (calcium deposition, intimal thickening, disruption and duplication of the internal elastic membrane, and alteration of cell types) were observed in aortas from calves in all treatment groups. These changes were more extensive in calves fed milk and cholesterol, but they occurred even in calves fed a low-fat, low-cholesterol diet.