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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

Kenneth F. Kalscheur


fermentable sugars, milk fat, slow-release urea


A study was designed to test the inclusion of a formula of liquid co-products from the com milling and cheese industries in dairy rations and their interaction with a source of nonprotein nitrogen, calcium chloride urea. Eight multiparous and four primiparous Brown Swiss cows (96 ± 46 d in milk) were blocked by parity and assigned randomly to three 4 x 4 Latin Squares with a 2 x 2 factorial arrangements of treatments. Basal diets were formulated for 16.6% CP and 1.55 Meal/kg NEL and contained 35% of dietary dry matter (DM) as com silage, 15% alfalfa hay, 34% of a varying concentrate mix of ground shelled com and soybean meal (SBM) and 16% of a constant premix. The constant premix contained equal proportions of soybean hulls, heat treated soybean meal, com distillers grains, vitamins and minerals across all diets. Treatments were: 1) no calcium chloride urea demonstrated to have slow-release properties and no fermentable sugars (NSU-NFS); 2) no slow-release urea with fermentable sugars (NSU-FS; 8.64% RationMate); 3) slow-release urea with no fermentable sugars (SU-NFS; 0.61 % Ruma Pro); and 4) slow-release urea and fermentable sugars in combination (SU-FS; 8.64% FS, 0.61 % SU). Feeding FS tended to decrease milk production and increased ruminal butyrate concentration compared to feeding NFS. Milk fat percent was also increased for cows fed FS compared with NFS. Feeding SU decreased DM intake, and increased feed efficiency compared with cows fed NSU. Dietary treatment had no effect on energy-corrected milk, milk protein percent, milk fat yield, milk protein yield, or milk urea nitrogen. No interactions between FS' and SU were observed. It is concluded that the replacement of com and SBM with dietary FS increased milk fat percentage while the replacement of ground com and SBM with SU significantly improved feed efficiency. However, no synergistic effects were observed when FS and SU were fed in combination.

Library of Congress Subject Headings

Dairy cattle -- Feeding and feeds
Urea as feed
Milk yield


Includes bibliographical references (pages 51-60)



Number of Pages



South Dakota State University


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