Ensiled Alfalfa Research Articles

DIGESTION IN THE RUMEN AND AMINO ACID SUPPLY TO THE DUODENUM OF SHEEP FED ENSILED AND FRESH ALFALFA

A study was conducted with six sheep equipped with rumen and duodenal re-entrant cannulae to investigate differences in duodenal amino acid supply with fresh and ensiled alfalfa. The experiment was conducted as a cross-over design with two 12-d periods consisting of an adaptation phase (5 d) followed by feces collection (5 d), and finally on day 12, 24 h continuous collection of duodenal digesta and sampling of rumen fluid. During the experiment the sheep were restricted on feed to 52 g DM d−1 kg−0.75. Analyses of the forages revealed extensive breakdown of threonine, lysine and other basic amino acids, and high degree of preservation of branched chain amino acids. Relative to the amount consumed, there was a net loss of amino acids at the duodenum with fresh alfalfa but a net gain with silage. The relationship between intake of individual essential amino acids and duodenal recovery was inconsistent. Duodenal recovery of total essential amino acids was 28% higher with fresh than with ensiled alfalfa, a difference which was most pronounced with threonine and lysine. Digestion of organic matter and fiber was unaffected (P > 0.05) by ensiling of alfalfa. Estimates of ruminal pH were higher (P < 0.05) for silage than fresh forage (6.9 vs. 6.7) but VFA concentrations were lower (P < 0.05) for silage (52.1 vs. 64.1 mmol L−1). Rumen ammonia levels were similar for the two forages. The deficit in duodenal supply of essential amino acids with silage is discussed in relation to the problem of silage intake in ruminants. Key words: Alfalfa silage, duodenal amino acids, sheep, rumen digestion

THE SIGNIFICANCE OF SILAGE PROTEIN DEGRADATION AND PLASMA AMINO ACID RATIOS IN THE CONTROL OF FOOD INTAKE BY LAMBS FED ENSILED AND FRESH ALFALFA

Alfalfa (30% dry matter) was harvested with a particle length of 0.6 cm, conserved fresh (frozen) or as silage and fed to eight lambs during two 27-d periods. The ensiling process resulted in substantial degradation of lysine, threonine, histidine, arginine, tryptophan and tyrosine in the original herbage. Isoleucine, leucine and valine resisted degradation during ensilage. As a consequence of these changes, the ratios of tyrosine: large neutral amino acids and tyrosine: phenylalanine (TYR:LNAA and TYR:PHE) were markedly lower in ensiled compared to fresh alfalfa (0.035 vs. 0.051 and 0.235 vs. 0.313, respectively) but these ratios in plasma were higher (P < 0.05) with silage than with fresh forage (0.114 vs. 0.095 and 1.020 vs. 0.997). Ensiling of alfalfa resulted in a 19% reduction in silage intake but the response did not correlate with changes in plasma ratios of TYR:LNAA and TYR:PHE. Nitrogen retention was 27% lower with ensiled than with fresh alfalfa. Plasma levels of branched chain and other essential amino acids tended to be higher with fresh than ensiled forage but the difference was not significant. It is concluded that the reduction in food intake with alfalfa silage was unrelated to changes in specific ratios of amino acids in plasma but could be related to the supply of essential amino acids to the intestine of lambs. Key words: Silage intake, lambs, nitrogen balance, plasma amino acids, alfalfa

Evaluation of Covering, Dry Matter, and Preservative at Ensiling of Alfalfa in Bunker Silos

In 1978, alfalfa at 30 or 40% dry matter was ensiled in four bunker silos. Propionic acid (.02% wet basis) was applied to one bunker of each dry matter. Bunkers were covered with black plastic. Dry matter recovery, temperatures during storage, and weight gain of heifers fed these silages were similar between treatments. In 1979, alfalfa (44% dry matter) was ensiled in four bunker silos of which two were not covered. Two silos, one covered and one not, were treated with propionic acid (.02% wet basis). Average temperatures during storage (7 wk) 34.1, 36.4, 42.6, and 50.3°C and dry matter recovery 84.1, 96.2, 86.3, and 68.0% were recorded for treated-covered, covered, treated-uncovered, and uncovered silos. Heifers gained more when fed untreated and covered silages. In 1980, alfalfa (32% dry matter) was ensiled in two bunkers. One silo was covered and untreated (covered), and the other was treated topically (treated) with a 100% propionic acid solution. Average temperatures during storage (7 wk) were 33.7 and 43.0° C, dry matter recovery 86.2 and 77.6%, average daily gain .58 and .44kg/day, and dry matter consumption 7.3 and 5.8kg/dry matter per day for silages or heifers fed covered and treated silages. In general, covering with black plastic was as effective as or more effective than treatment with propionic acid for preserving alfalfa stored in bunker silos.

CHANGES IN THE LEVELS OF PROTEOLYTIC ENZYMES IN ENSILED ALFALFA FORAGE

The activities of several proteolytic enzymes were quantified in ensiled alfalfa (Medicago sativa) forage and their activities were related to proteolysis in the ensiled crop. The enzymes studied were carboxypeptidase at pH 5.2, aminopeptidase at pH 7.0, and acid proteinase against hemoglobin at pH 4.5 and azocasein at pH 5.5. Proteolysis, which was measured as the increase in trichloroacetic acid-soluble, non-protein nitrogen, occurred during the first 1–2 days after ensiling. Silage pH was above 5.5 during the time period of proteolysis. The rate of proteolysis in the ensiled herbage was approximately 25 μmoles amino acid released per gram dry weight per hour, and can be accounted for by the activity of proteolytic enzymes in alfalfa herbage without consideration of microbial enzymes. The activity of the alfalfa proteolytic enzymes declined with time after ensiling, but each enzyme declined independently. For example, the proteinase at pH 4.5 was inactive after 2 days whereas carboxypeptidase retained 45% of its activity even at 21 days after ensiling. The cessation of proteolysis after 2 days ensiling was not due to the lack of proteolytic enzyme activity nor was pH completely inhibitory. The results are further discussed in regard to the regulation of proteolysis during ensiling.

Wet Plant Fractionation: Utilization of Pressed Alfalfa Silage

Three lactation trials and two digestion trials were performed comparing mechanically pressed ensiled alfalfa with similar material which was field-wilted before ensiling. Pressed alfalfa contained significantly (P<.05) less dry matter, crude protein, and ash; and more cell wall constituents than the wilted forage, and these trends were transposed into their resulting silages. The pressed silage contained a greater (P<.05) concentration of acetic and butyric acids and nonprotein nitrogen than the wilted silage. Lactic acid concentration in the pressed silage tended to be lower than that of the wilted silage. Over the three lactation trials, silage dry matter consumption, production of milk, and 4% FCM were an average of 8.9, 6.3 and 7.5% lower in animals fed pressed silage. Supplementation of the silage-based diets in Lactation Trial 3 with 2 kg of alfalfa hay increased the total dry matter intake of both groups but didn't alleviate the difference in intake between the two silages. The percentage of rumen acetic acid was higher while that of propionic acid was lower in the pressed silage-fed animals. Ruminal ammonia concentrations also tended to be lower for this group. Although dry matter digestibility of the pressed silage tended to be lower than that of the wilted silage, the only differences (P<.05) observed were an increase in the digestibility of crude protein and a decrease in that of acid-detergent fiber in Digestion Trial 1.

Influence of alfalfa harvesting and storing methods on steer performance

Three alfalfa treatments were evaluated in a steer performance trial: (1) direct-cut and ensiled with dry milo, (2) field-wilted and ensiled, with milo added at feeding and (3) baled, with milo added at feeding. The rations contained 45.4, 50.9 and 48.1 percent milo, respectively. During the 84-day trial, yearling steers made similar gains on the three rations. Direct-cut and ensiled alfalfa produced the most efficient gain; hay the least efficient. Potential beef gain per acre of alfalfa was lowest from baled hay.

NEW BIOLOGICAL PREPARATION FOR ALFALFA SILAGE MAKING

The data on assessment the preservative action of new enzymatic multisystem in combination with bacterial silage additive Silzak at alfalfa ensiling are presented in this study. It is known that alfalfa is a nonensiling legume grass because of excess moisture, sugar deficit and high content of crude protein. The experiments on alfalfa ensiling were conducted with application the enzymatic multisystem FM-1 under laboratory and research-and-production conditions. The multisystem was developed by the specialists of science-and-technical centre «Lecbiotech» in cooperation with scientists of Williams Fodder Research Institute. The optimal dose of FM-1 application and its preservative effectiveness in comparison with chemical conservant were determined in technological experiments. Obtained silage was evaluated on basic parameters: nutrients and organic acids content, ammonia, active acidity. The influence of the tested biological additive on the nutrients digestibility and energy value of alfalfa silage was estimated in experiments with hog lambs. Total results have shown the efficiency of the new development. Lucerne silage, prepared with application of mixture FM-1 and Silzak, was characterized by the better parameters of nutrients digestibility and energy value than at using a chemical conservant AIV 3 plus. The optimal dose of enzymatic multisystem application, as 90 gram per ton of fresh plant mass, was determined in the series of experiments.

Studies on ensilage. I. A comparative laboratory study of molasses and sodium metabisulphate as aids to the conservation of lucerne

The relative effects of molasses and sodium metabisulphite on changes occurring in ensiled lucerne have been investigated. Under certain conditions, both additives have been shown to be of great benefit to the conservation process: molasses by increasing the intensity of the lactic fermentation, and metabisulphite by preferential inhibition of undesirable fermentative changes. The proportion of molasses needed for best results has been found to vary with the maturity of the lucerne at harvest, but the effects of metabisulphite are less dependent on this factor. Benefits which accrue from both additives are adversely affected by silage temperatures of 30°C and above, especially in the case of metabisulphite. Some practical implications of these observations are discussed.