Intake and Digestibility of Brown-Midrib Corn Silage by Lactating Dairy Cows

Author

James Allen Rook

Document Type

Thesis - Open Access

Award Date

1976

Degree Name

Master of Science (MS)

Department / School

Dairy Science

Abstract

Two short-term trials evaluated brown-midrib-3 (bm₃) mutant (low lignin) corn silage for early lactation Holstein cows. In trial 1, five cows per group were individually fed a ration of silage and grain (60:40 ratio, dry matter basis) from week 2 through 8 of lactation. Lignin percentages for bm₃ and normal silages were 4.9 and 6.4. Cattle fed the bm₃ ration consumed 19% more total dry matter as percent of body weight than cows fed normal. Digestibilities of dry matter, cell-wall contents, acid detergent fiber, and energy were 3 to percentage units higher for the bm₃ ration. Milk yield was not affected by ration, but milk fat percentage was higher for cows fed the bm3 ration. Total ruminal volatile fatty acids, pH, and ammoniacal nitrogen levels were similar. In trial 2, five cows per group were individually fed a ration of either ~ 3 or normal silage supplemented with a concentrate at an 85:15 silage to concentrate ratio (dry matter basis). Lignin percentages were similar. Lactic acid was higher and pH lower for bm₃ silage. All parameters of daily dry matter intake were higher by cows fed the bm₃ ration. Digestibilities of fiber components, energy, and nitrogen showed little difference between rations. Total digestible energy intake was 21.6% higher for cows fed the bm₃ ration. Milk and milk component yields did not differ between treatments. Total and individual rumen volatile fatty acids were higher and pH lower for cows fed the bm₃ ration. No difference existed in rumen ammoniacal nitrogen.

Library of Congress Subject Headings

Dairy cattle -- Feeding and feeds
Corn -- Silage
Digestion

Description

Includes bibliographical references (pages 78-83)

Format

application/pdf

Number of Pages

100

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

Recommended Citation

Rook, James Allen, "Intake and Digestibility of Brown-Midrib Corn Silage by Lactating Dairy Cows" (1976). Electronic Theses and Dissertations. 1284.
https://openprairie.sdstate.edu/etd/1284