From William Campbell Douglass, MD: The Milk Book
"Dr. T.W. Gullickson, Professor of Dairy Chemistry, University of Minnesota, proved the nutritional superiority of butterfat over vegetable oils, which are the main ingredients of the vegetable margarines.
Gullickson used skim milk and combined it with lard, tallow, coconut oil, corn oil, cottonseed oil or soybean oil in place of the cream and fed it to the calves. The vegetable oil substitutes were mixed with skim milk in an attempt to imitate the 3.5 percent butterfat of milk.
As often happens in research, they proved something entirely different from their original objective. They had set out to find a cheaper way to raise calves for veal production. What they found was that calves will only grow on God's own natural milk, and when fed vegetable oil substitutes instead of the cream, they sicken and die.
On the corn oil mix three out of eight died within one 177, some as soon as 33 days. On cottonseed oil three out of four died within 126 days. Pick your favorite vegetable oil- the result was the same.
The survivors quickly recovered when switched to whole raw milk. If vegetable oil products are so devastating to the health of calves, do you think maybe they are bad for you, too?"