Evaluation of Alfalfa-Brome Forage Stored as Wilted Silage, Low-Moisture Silage, and Hay1,2

Abstract

First-growth alfalfa-brome forage was harvested and stored as field-cured hay, low-moisture silage, and wilted silage in 1961, 1962, and 1963. Silages were stored in concrete-stave tower silos. Each year the experimental forages were evaluated in terms of chemical quality and feeding value.Method of preservation influenced the chemical composition of the forage when fed. Forage preserved as hay was lower in protein, ether extract, and ash than that preserved as low-moisture silage or wilted silage. Wilted silage contained the most carotene, and hay contained the least. Ammoniacal nitrogen constituted a greater proportion of the total nitrogen in wilted silage than in low-moisture silage. Wilted silage had a greater total acid content than did low-moisture silage. Butyric acid was the predominant acid present in wilted silage, and lactic acid predominated in low-moisture silage.Cows fed low-moisture silage consumed more dry matter than cows fed wilted silage. More dry matter was consumed from low-moisture silage than from hay during two of three trials. Cows fed low-moisture silage or hay gained more body weight than cows fed wilted silage. Low-moisture silage ranked first in supporting 4% fat-corrected-milk production, wilted silage ranked second, and hay last. Fat test of cows fed wilted silage was higher than that of cows fed low-moisture silage. Fat test of cows fed low-moisture silage was, in turn, higher than that of cows fed hay.Feeding wilted silage resulted in a higher proportion of rumen butyrate and lower proportions of rumen acetate and propionate. Blood sugar concentrations were lower and blood ketones higher for cows fed wilted silage.Digestion trial results were inconsistent from year to year. However, each year the nitrogen of hay and wilted silage was digested to a greater extent than that of low-moisture silage.