Effect of forage type and supplemental dietary vitamin E on milk oxidative stability

• Published in: Canadian journal of animal science Vol. 71; no. 4; pp. 1181 - 1186
• Main Authors: Nicholson, J.W.G, St Laurent, A.M
• Format: Journal Article
• Language: English
• Published: 01-12-1991
• Subjects: alfalfa silage; corn silage; dairy cows; milk; oxidation; oxidized flavor; stability; vitamin E; vitamin supplements
• ISSN: 0008-3984; 1918-1825
• DOI: 10.4141/cjas91-139

Twelve Holstein cows in each of two replicates were used to determine the effect of forage type and vitamin E supplementation on the oxidative stability of milk. Alfalfa or corn silage was fed ad libitum as the sole roughage, with a concentrate to milk ratio of 1:2.5. Half the cows on each forage were fed 7000 IU d
−1
of dL-α-tocopherol acetate top-dressed on the concentrate in two feedings per day over a 4-wk period. Cows consuming the alfalfa silage had higher (P < 0.05) plasma vitamin E content, but there were no differences in milk vitamin E or flavor due to forage type. Supplementing the diets with vitamin E resulted in higher (P < 0.01) vitamin E content of plasma and milk and improved milk oxidative stability. There was an interaction (P = 0.03) between forage type and vitamin E supplementation for oxidative flavor score in week 2. Supplementing the corn silage diet with 7000 IU d
−1
of vitamin E resulted in almost complete elimination of oxidized flavor in milk within 1 wk of starting supplementation. However, supplementing the alfalfa silage diet had no effect on flavor over the first 3 wk of feeding. It is apparent that the vitamin E content of milk is not the sole determinant of its oxidative stability. Key words: Spontaneous oxidation, flavor, milk, vitamin E, alfalfa, corn silage, cow