The Eeffect of Shark Liver Oil on Milk and Butter Fat Production

The detrimental effect of cod liver oil upon milk and butter fat production has been shown by Golding et al. (6) and others (7,9,11).Recently Deuel and co-workers (2, 5) reported that the feeding of shark liver oil high in vitamin A potency increased the milk and butter fat production of Guernsey cows 10 per cent or more.These workers fed 30 to 60 cc. of shark liver oil daily which was sufficient to furnish a daily intake of 700,000 to 1,400,000 I.U. of vitamin A. Practical farm supplements of shark liver oil with a vitamin A potency of 7,500 I.U.per gram have been fed to milking cows at the rate of 15-25 grams per cow per day without any noticeable effect upon either milk or butter fat production (13).Further experiments have recently been conducted to determine the effect of shark liver oil feeding upon milk production, butter fat percentage and vitamin A in blood plasma and milk.The results of these experiments are reported herewith.