Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Dairy Science


A 14 wk lactation trial was conducted to evaluate the feeding value of brown-midrib (bm3) corn silage and its normal (N) genetic counterpart using ten Holstein cows per group averaging 6 wk post-partum at the start of the experiment. The cow were fed corn silage (bm3 or N) ad libitum, 2.25 kg alfalfa hay/hd and grain (1 kg/3 kg milk produced) dairy. The bm3 and N, respectively. Milk production for cows fed bm3 and N was 25.0 and 25.5 kg/day. Fat corrected milk and solids corrected milk were similar for both groups. A total collection digestion trial was conducted with six cows from each group at the end of the laction trial. Digestibilities for bm3 and N ration were, respectively: dry matter, 62.9% and 59.5%; cell wall constituents, 60.1% and 50.5%; lignin, 50.9% and 44.3%; cellulose, 59.9% and 53.2%; hemicellulose, 66.5% and 62.8; and energy, 62.4% and 59.0%. There was no difference in nitrogen utilization for the two silage rations. Rumen sample were taken via the stomach tube at 0, 3, 6, 9 and 12 hr post-feeding the last day of the digestion trial. Concentrations of total volatile fatty acids (59.8 and 66.7 moles/ml for bm3 and N) and butyrate (9.7 and 11.9 moles/ml) were greater for the N fed cows. Rumen pH was lower for N, while rumen ammonia was similar for both groups. Analysis of blood samples taken at the time of rumen sampling from the jugular vein showed that blood glucose and urea nitrogen concentrations were similar for both groups.

Library of Congress Subject Headings

Dairy cattle -- Feeding and feeds
Corn -- Silage


Includes bibliographical references (pages 38-43)



Number of Pages



South Dakota State University


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