Date of Award:

5-1978

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Animal, Dairy, and Veterinary Sciences

Advisor/Chair:

Melvin J. Anderson

Co-Advisor/Chair:

John E. Butcher

Third Advisor:

Robert C. Lamb

Abstract

Thirty-two lactating cows were assigned at random to four treatments of malic acid to determine if these levels had an effect on milk production, milk composition, feed intake, and efficiency of feed utilization. Malic acid allotment for each treatment consisted of 1) 15.4, 2) 11.6, 3) 7.7, and 4) 0 grams of malic acid fed per kilogram of concentrate. Concentrate was fed according to production at a rate of one kilogram per two kilograms of milk in excess of 9.1 kilograms of milk per cow daily. Alfalfa hay was fed free choice and corn silage at a rate of 11.4 kilograms daily. The cows were on the trial for 8 weeks. Intake of concentrates, silage, dry matter, and digestible energy was highest for cows receiving the 11.6 g level of malic acid. These intakes were significantly higher than for the 7.7 g level but not for the other treatments. However, cows on the 7.7 g level consumed only slightly less feed than control cows. There was no significant effect on hay or crude protein intake. Production of total milk, fat corrected milk, and milk fat was significantly higher for cows receiving the 11.6 g level of malic acid than from the 7.7 g level or control cows. Production of protein solids-not-fat was significantly higher for the 11.6 g level than from the 7.7 g level and approached this level of significance when the 11.6 g level was compared to the controls. Cows receiving the 11.6 g level of malic acid were significantly more efficient in converting dry matter or digestible energy from feed into milk than were the controls. Intakes and production of cows on the 15.4 g level was slightly less than for the 11.6 g level.

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