Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

Andrew K. Clark


The preservation efficiency of covering alfalfa haylage with black plastic (polyethylene) and/or treating haylage with propionic acid was studied in two trials. Experiment 1 was designed to evaluate the influence of both covering and treatment with propionic acid on haylage chemical composition and heifer growth. In experiment 1, prop ionic acid was administered to the haylage at the chopper at 0.02% of the fresh forage weight. Chemical composition and ensiling temperature of the haylage were monitored and animal growth was measured with 16 Holstein heifers. Covered haylage was superior to treated haylage in quality as measured by chemical analyses and animal performance. Propionic acid lowered ensiling temperature to a lesser extent than covering. Experiment 2 was designed to compare a control alfalfa haylage (covered/untreated) to an uncovered haylage topically treated with 100% propionic acid. Ensiling temperature, chemical content, and animal performance of dairy heifers were evaluated. The control haylage had lower ensiling temperature and was superior in quality as measured by chemical analyses and heifer performance. Propionic acid addition was ineffective in lowering ensiling temperature and limiting extended fermentation. The data suggests that covering was more efficient than propionic acid addition in preserving alfalfa haylage in bunker silos.

Library of Congress Subject Headings

Alfalfa -- Silage
Propionic acid
Protective coverings


Includes bibliographical references (pages 86-97)



Number of Pages



South Dakota State University


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Dairy Science Commons