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Joby Cyriac

Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

Kenneth F. Kalscheur


Eight primiparous and eight multiparous lactating Holstein cows were used in a replicated 4 x 4 Latin square design to evaluate the effect of replacing forage fiber with non-forage fiber source on the performance of the dairy cows. Four diets were formulated to replace corn silage with dried corn distillers grains with solubles (DDG) at 0, 7, 14, and 21 % (DM basis). The control diet contained 40% corn silage, 15% alfalfa hay, and 45% concentrate (DM basis). Soybean meal was replaced with soybean hulls as the percentage of DDG increased in the diets. Alfalfa hay was equal for all diets. Replacing corn silage with DDG increased the proportion of feed particles, as fed basis, passing through the 1.18 mm sieve of the Penn State Particle separator. Dry matter intake increased with increasing concentrations of DDG in the diet. Total NDF and non-forage NDF in the diets were increased while forage NDF was decreased significantly as DDG replaced corn silage in the diet. Milk protein percentage, protein yield, milk lactose percentage and lactose yields were increased. Milk fat percentage, fat yield and feed efficiency were decreased as the percentage of DDG increased in the diets. Milk yield, energy-corrected milk and milk urea nitrogen were not altered because of diet. As a result, molar proportion of ruminal acetate decreased and propionate increased as DDG increased in the diet. Replacing forage fiber with non-forage fiber in lactating dairy cow diets increased DMI and decreased milk fat percentage and did not change fat-corrected milk yield. Dried com distillers grains with solubles did not provide necessary effective fiber to maintain normal milk fat production. When formulating diets with DDG, it is critical that sufficient effective fiber is included in the diet to prevent milk fat depression.

Library of Congress Subject Headings

Dairy cattle -- Feeding and feeds
Fiber in animal nutrition
Distillers feeds


Includes bibliographical references (pages 46-56)



Number of Pages



South Dakota State University


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