Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

David J. Schingoethe


Digestibilities of rations containing 10% (dry matter basis) oil-type, rolled sunflower seeds treated with three levels- of calcium hydroxide were compared using .a randomized complete block design. Forty-eight Holstein steers were fed one of six completely mixed rations consisting of (DM basis) 44% corn silage, 10% chopped alfalfa hay, and 46% concentrate mix. Concentrate mixes contained: CSM = control; SCS =control+ 22% sunflower seeds; SCL = SCS + 3.5% additional limestone; SCH2, SCH4, and SCH8 = SCS + 2, 4, and 8% calcium hydroxide (% sunflower seed DM), respectively. Total rations were isonitrogeneous at approximately 16% crude protein and isocaloric at 4.2 MCal/kg. Steers were adapted to diets for 13 days followed by a 5 day total collection of feces and urine. Dry differences in actual volatile fatty acid concentrations among treatments. Rumen pH, rumen ammonia, and serum urea levels were similar for all treatments. Analysis of rumen fluid dry matter (RFDM) indicated an increase in total fatty acid (TFA) concentrations with sunflower rations as compared to CSM, while calcium supplementation, especially with calcium hydroxide, caused a decrease in TFA concentrations. Sunflower rations caused an increase in insoluble· fatty acid soaps (IFAS) i~ RFDM, but additional calcium did not result in a further increase in IFAS. This indicated sufficient calcium was present to form IFAS to the maximum extent possible given the conditions of this study. Compared to limestone, calcium hydroxide increased the unsaturated nature of the IFAS in the RFDM, which may have resulted in increased fiber digestibility with these rations as compared to SCL. The results of this study indicated that the utilization of rolled sunflower seeds in ruminant rations may be improved by treating sunflower seeds with 2 to 4% calcium hydroxide; however, further identification of the specific merchanisms involved is warrented.

Library of Congress Subject Headings

Cattle -- Feeding and feeds
Sunflowers -- Seeds


Includes bibliographical references (pages 53-58)



Number of Pages



South Dakota State University


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Dairy Science Commons