Combining corn with legumes for silage is a feasible strategy to improve crude protein concentration in corn silage. This study was conducted to determine the fermentation characteristics and overall nutritive value of ensiled corn (Zea mays L.), vine peas (Pisum sativum L.), and mixtures of the two crops at three different ratios. The two crops were ensiled in corn/pea mixtures containing 0, 33, 50, 67, and 100% corn in vacuumed plastic bags for 60 days at room temperature. The addition of peas to corn crude protein and dry matter concentrations in the ensiled forages had a negligible influence on neutral detergent fibre concentration compared with corn silage. Corn silage had a greater (P < 0.05) lactic acid concentration than vine peas silage and the mixtures. There were no differences (P > 0.05) in in vitro dry matter and neutral detergent fibre digestibility among the silages made from the vine peas, corn, and mixtures. Improved fermentation characteristics were obtained in vine peas and corn mixture silage at a ratio of 33 : 67 compared with the other mixtures and vine peas silage. Results generated from this study suggest that combining vine peas with corn for silage could provide livestock with not only a high energy concentration feed, but a high concentration of crude protein as well.

Effects of different chemical additives on peptide composition in ensiled alfalfa (Medicago sativa L.) were investigated by using gel filtration and determination of N characteristics. The alfalfa silages were prepared untreated (control) or with formic acid, formaldehyde or tannic acid as additives at ensiling. All additives reduced non-protein N (NPN), ammonia nitrogen (NH3 -N) and amino acid N (AA-N) in the ensiled forage, and the most effective reduction of NPN and AA-N was observed in the formaldehyde-treated silages. Peptides in the control silage were mainly dipeptides to peptides with five amino acid residues. Most peptides in the formic acid-treated silage contained 4-12 amino acid residues. Although most peptides in the formaldehyde-treated silages contained 4-6 amino acid residues, there was a considerable proportion of peptides with 7-11 amino acid residues. Tannic acid had little effect on peptide size of ensiled alfalfa extract in which most peptides contained 5-6 amino acid residues. Peptide size in formic acid-treated alfalfa silage was greater than that in the other treatments. Addition of formic acid and formaldehyde not only increased the peptide concentration in alfalfa silage, but enlarged the peptide size.

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