Factors Affecting Bag Silo Densities and Losses

Bag silos (polyethylene tubes, 30 to 90 m length, 2.4 to 3.7 m diameter, 0.22 mm thick) are used on approximately one-third of the dairy farms in the U.S.A. for making silage, and the level of adoption is increasing rapidly. Unfortunately, almost no research data have been published on these types of silos. Our objective was to measure densities and losses in bag silos at three farms, looking for causes of variation in both

Conserved Forage (Silage and Hay): Progress and Priorities

Forage conservation permits a better supply of quality feed when forage production is low. While haymaking and ensiling have been practiced for generations, research is still needed to 1) understand the processes affecting quality during harvesting and storage and 2) develop practical means to minimize losses and enhance quality. Several trends in harvesting forages for silage are notable. Kernel processing of maize, once confined to Europe, has become popular in North America. Self-propelled forage harvesters have a larger share of the market due to more contract harvesting and larger farms. Larger harvesters, rakes and mergers help improve productivity and forage quality. Finally, farmers are increasing cutting length to meet the fiber needs of high-producing dairy cattle. These latter two trends make good silo management more critical. The number of silo types has continued to increase. Pressed bag and wrapped bale silages are important recent developments. These newer types have made it easier to segregate silages by quality and allow small farms to make high quality silage. However, disposal of the larger quantities of plastic is a growing issue. Alternatives such as edible or biodegradable films would be welcome for all silo types, reducing labor and environmental concerns. With wrapped bales, spoilage and listeria contamination are more common because of the large surface to volume ratio. Enhanced methods to control spoilage and pathogen development are needed. With most crops considerable breakdown of true protein occurs during ensiling, subsequently decreasing nitrogen utilization efficiency in ruminants. The polyphenol oxidases in red clover and the tannins in some legumes reduce protein loss during ensiling. These mechanisms may be useful in developing new silage additives or plant varieties. Additives can enhance silage quality. Inoculants are the most common. Improved inoculants aimed at increasing aerobic stability are beginning to be marketed, but their overall success is uncertain. Enzymes to degrade plant cell walls, providing sugar for fermentation and making the silage more digestible, have not fulfilled their promise but do have potential. Acids and sugars have been declining in use but still are important in certain ensiling situations. Three types of balers are used to package dry hay: small square (SSB), large round (LRB) and large square balers (LSB). The SSB is declining importance in developed countries because of labor constraints but remains viable in developing countries where farm labor is still plentiful. The LRB is the dominant baler worldwide because of its productivity and low ownership and operating costs. High productivity and a package ideally suited for shipping has promoted the continuing growth of the LSB. Hay producers struggle with getting crops dry enough (\u3c 20% moisture) to prevent excess storage losses due to biological activity. This is especially important as bale density increases. Typical bale densities are about 130, 190 and 240 kg/m3 for SSB, LRB and LSB, respectively. In humid climates, forage researchers and producers are investigating intensive conditioning systems to improve field drying rates, utilizing preservatives like propionic acid, and developing bale ventilation and drying systems all in the attempt to improve dry hay quality. In arid regions, producers only bale after dew accumulation has softened brittle plant tissue to reduce leaf loss. Systems are under development that will soften plant tissue at the baler by applying a fine water mist. Larger livestock farms and increased development of markets for commercial hay will push demand for greater productivity and better bale quality

Using the Red Clover Polyphenol Oxidase Gene to Inhibit Proteolytic Activity in Lucerne

Preserving high quality forage in cool humid regions of agricultural production remains a challenge due to potentially high levels of protein degradation during ensiling. Red clover is an exception maintaining its high protein levels during ensiling. Decreased proteolytic activity in red clover is due to polyphenol oxidase (PPO) activity and appropriate o-diphenol substrates (Jones et al., 1995, Sullivan et al., 2004). This work highlights potential strategies for utilising PPO as a means of decreasing proteolytic degradation during the ensiling of lucerne and other forages

Inoculant Effects on Ensiling and \u3ci\u3ein Vitro\u3c/i\u3e Gas Production in Lucerne Silage

Inoculants are the most common additives used in making silage. While inoculant effects on fermentation and dry matter (DM) recovery are understood, animal performance effects are often greater than expected. In vitro analyses may help uncover how inoculants affect rumen fermentation and ultimately dairy cattle performance. Our objective was to study how inoculation of lucerne silage affected in vitro gas production

Effects of Feeding Legume Silage With Differing Tannin Levels on Lactating Dairy Cattle

Condensed tannins (CT) bind to plant proteins in the rumen, reducing protein degradation to ammonia and increasing milk production and milk protein (e.g. Waghorn, 1987). Previous research showed that the reduced soluble non-protein nitrogen (NPN) content of red clover (Trifolium pratense) silage (RCS) was related to its greater N efficiency relative to lucerne (Medicago sativa) silage (LS) (Broderick et al., 2001). Commercial cultivars of birdsfoot trefoil (Lotus corniculatus; BFT) contain modest levels of CT which reduce NPN formation in silage (Albrecht & Muck, 1991). The objective was to compare silages made from BFT with RCS and LS for milk production and N efficiency in lactating dairy cows

\u3cem\u3eIn Vitro\u3c/em\u3e Gas Production and Bacterial Biomass Estimation for Lucerne Silage Inoculated With One of Three Lactic Acid Bacterial Inoculants

Silages inoculated with microbial inoculants frequently have a lower pH than non-inoculated crops. Less often inoculated crops have a positive effect on milk production (Weinberg & Muck, 1996). One hypothesis is that bacterial inoculants produce a probiotic effect that could enhance animal performance (Weinberg & Muck, 1996). Our objective was to use the method of Blümmel et al. (1997) to study differences in in vitro fermentation among lucerne silages inoculated with three microbial inoculants

Inoculant effects on alfalfa silage: Fermentation products and nutritive value

The effect of 14 microbial inoculants on the fermentation and nutritive value of alfalfa silages was studied under laboratory conditions. The first cut (477 g of dry matter/kg) and second cut (393 g of dry matter/kg) of a second-year alfalfa stand were ensiled in 2 trials. In both trials alfalfa was harvested with standard field equipment. All inoculants were applied at 1.0 x 10(6) cfu/g of crop. Uninoculated silages served as controls. After inoculants were added, the chopped forages were ensiled in 1.0-and 0.5-L anaerobic glass jars, respectively, at a density of 500 g/L. Each trial had 15 treatments (uninoculated control and 14 inoculants), with 4 silos per treatment. Silos were stored for a minimum of 30 d at room temperature (similar to 22 degrees C). In first-cut silage, all inoculants but one reduced pH relative to the uninoculated control, and all but 2 of the homofermentative strains shifted fermentation toward lactic acid. In second-cut silage, the epiphytic lactic acid bacterial population was 2.7 x 10(7) cfu/g, and only commercial inoculants produced significant shifts in fermentation. Overall, microbial inoculants generally had a positive effect on alfalfa silage characteristics in terms of lower pH and shifting fermentation toward lactic acid with homofermentative lactic acid bacteria or toward acetic acid with heterofermentative lactic acid bacteria, Lactobacillus buchneri. These effects were stronger in the commercial products tested. In spite of the positive effects on silage fermentation, 48-h in vitro true DM digestibility was not improved by inoculation with lactic acid bacteria

Inoculant effects on alfalfa silage: In vitro gas and volatile fatty acid production

Alfalfa silages from 2 similar trials were analyzed for in vitro ruminal gas production. In both trials, there were 15 treatments: alfalfa treated at ensiling with 1 of 14 lactic acid bacterial inoculants or untreated alfalfa. First-cut (477 g of dry matter/kg) and second-cut (393 g of dry matter/kg) alfalfa were ensiled in glass jars for a minimum of 35 d at room temperature (similar to 22 degrees C). At opening, a portion of each silage was wet-ground with a mixer. Each silage was then assessed for in vitro ruminal gas production in 3 replicate runs with the wet-ground silage, 1 on the fresh silage and 2 on frozen and thawed silage. In vitro gas production was measured in 160-mL sealed serum vials incubated at 39 degrees C. One gram of silage was incubated with 17.1 mL of nutrient solution, 0.9 mL of reducing solution, and 12 mL of ruminal inoculum (1: 2 vol/vol mixture of rumen fluid and buffer). Gas production was measured manually by using a pressure gauge at 3, 6, 9, 24, 48, and 96 h. At 96 h, the rumen fluid was analyzed for pH and volatile fatty acids. In the 2 trials, the untreated control silage produced either numerically the highest or one of the highest levels of gas production per unit of dry matter incubated. In first-cut silage, 9 of the inoculant treatments at 9 h and 4 treatments at 96 h had reduced gas production compared with the control. In second-cut silage, 10 inoculant treatments at both 9 and 96 h had reduced gas production compared with the control. Furthermore, in first-cut silage, the fraction of total gas production at 3, 6, and 9 h was numerically the highest for the control, and only 4 treatments were not significantly lower than the control at 9 h. In second-cut silage, 2 of 14 inoculated treatments produced faster fractional rates of gas production than the control, but most inoculated treatments had numerically slower fractional rates (4 significant) in the first 9 h. The in vitro fermented wet-ground control silages had one of the highest acetate: propionate ratios in both trials, significantly higher than 12 and 8 of the inoculated treatments in first- and second-cut silage, respectively. The response in acetate: propionate ratio in both cuts was similar, even though the control silage was highest in lactic acid in one trial and lowest in the other. Overall, inoculation of crops at ensiling appears to affect in vitro ruminal fermentation of wet-ground silages, even in the absence of large effects during silage fermentation

Holography for fermions

The holographic interpretation is a useful tool to describe 5D field theories in a 4D language. In particular it allows one to relate 5D AdS theories with 4D CFTs. We elaborate on the 5D/4D dictionary for the case of fermions in AdS$_5$ with boundaries. This dictionary is quite useful to address phenomenological issues in a very simple manner, as we show by giving some examples.Comment: 22 pages, 2 figures; v2: minor corrections, references adde