Changes in the amino acid composition during the ensiling of lucerne and red clover in round bales

Changes in the amino acid profile of protein during ensiling depend on the proteolytic potential of plant species, the rate of the wilting and acidifying of ensiled herbage and, on the other hand, on the microbiological processes and fermentation of amino acids. The interaction of these factors determines the subsequent efficiency of nitrogen utilization in the rumen. The aim of this study has been to determine the influence of ensiling in round bales on changes in the amino acid content in lucerne and red clover silages. The amino acid composition was determined by analyzing the content of amino acids in herbages and silages. The lucerne silage protein was characterized by a higher contribution of all amino acids except Trp in comparison with red clover silage. Ensiling in bales of wilted lucerne and clover herbage lowered the content of Asp, His (P < 0.01), Ile, Lys (P < 0.05) in both plants. The ensiling process and plant species affected (P < 0.05) the total content of amino acids per 100 g of protein, where the range of changes in both raw materials was different. The loss of amino acids observed during the ensiling of wilted lucerne in round bales should be regarded as typical, whereas changes in the amino acid profile of red clover should be considered as atypical. A significantly higher ADIN content in red clover than in lucerne silage indicates that a rapid and significant increase of temperature occurred in experimental bales, which were characterized by a low degree of density, and this temperature rise strongly affected the availability of amino acids of the red clover protein also to the current microflora in the silage. Ensiling in round bales changed the amino acid profile of the lucerne and red clover protein. The ensiling process in this technology, however, severely deteriorated the quality of the red clover protein by lowering the content of all essential amino acids except Cys and Met.