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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

David Casper


dairy cow, feed efficiency, milk production, Saccharomyces cerevisiae fermentation products


This study was conducted to evaluate Saccharomyces cerevisiae fermentation products (Diamond V Original XPC and 2 prototypes) on production efficiency of mid lactation dairy cows. Eighty mid-lactation (164.5 DIM ± 67.5) Holstein cows (56 multiparous and 24 primiparous) were blocked by parity, days in milk, and milk production, and randomly assigned to one of 4 treatments. Treatments consisted of (1) Control (CON): corn silage and haylage based ration; (2) XPC: CON ration with Original XPC added at 14 g/hd/d; (3) Prototype 1 (P1): CON ration with Prototype 1 added at 5 g/hd/d; and (4) Prototype 2 (P2): CON ration with Prototype 2 added at 19 g/hd/d. Treatments were mixed with dried distillers grains and then mixed into a TMR at 454 g/hd/d. The study lasted for 70 d. The first 14 d of the study (d −14 to 0) was used to train cows to use the Calan gate feeding system and cows were fed the C ration during this period. Treatment effects were continuously monitored for the 8 wk experimental period. Dry matter intakes (DMI) were similar (P ≥ 0.10) when cows were fed all treatments (25.7, 26.1, 25.1, and 26.2 kg/d for C, XPC, P1, and P2, respectively). Milk production (33.3, 34.4, 35.5, and 36.8 kg/d) was improved (P < 0.05) for cows fed P2 compared with cows fed CON, with cows fed other supplements being intermediate and similar. Feed efficiency (Milk/DMI) was improved (P < 0.08) for cows fed P1 and P2, compared with x cows fed CON and XPC (1.30, 1.34, 1.49 and 1.41kg/kg). Milk fat content was reduced (P < 0.05) for cows fed P2 (4.17, 3.93, 4.08, and 3.85%) compared with cows fed CON, with cows fed other treatments being intermediate. Milk protein and lactose percentages were similar (P ≥ 0.10) among treatments. Cows fed P2 had lower (P < 0.05) molar percentages of ruminal acetate (63.8, 64, 63.1, and 62.3%) and greater (P < 0.05) propionate (18.9, 19.3, 19.7, and 20.6%) than cows fed other treatments. Supplementing a dairy ration with Saccharomyces cerevisiae fermentation products can improve milk production and feed efficiency of mid-lactation cows.

Library of Congress Subject Headings

Dairy cattle -- Feeding and feeds Saccharomyces cerevisiae Lactation Fermentation


Includes bibliographical references (page 41-61)



Number of Pages



South Dakota State University



Rights Statement

In Copyright