Effect of Different Lipids in Ration of Lactating Dairy Cows on Composition of Milk

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Abstract
Twelve Holstein cows were assigned to three blocks of a 4 × 4 Latin-square ex- perimental design. The within-block treat- ments were: control, 1% Degras wool fat (48.3% cholesterol), 1% mixed soy sterols and a mixture of 0.5% Degras fat, and 0.5% of soy sterols of the concentrate mix- ture. The concentrates between blocks con- tained no added fat, 10% animal tallow, or 10% vegetable oil. Milk fat produc- tion, fat test, and fat-corrected milk pro- duction were highest when no sterol was added to the ration. Percentages solids- not-fat, milk cholesterol, and blood fat were apparently not affected by the differ- ent sterols. However, cows. had lower blood cholesterol when a mixture of animal and plant sterols was fed compared to other groups. Milk production, milk fat production, fat-colTected milk, blood fat, and blood cholesterol were significantly higher when either tallow or vegetable oil was fed. However~ milk fat test was significantly lower. Milk fat production, solids-not-fat, and milk cholesterol were not significantly affected by fat source.
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