472 research outputs found
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
Logarithmic conformal field theories and AdS correspondence
We generalize the Maldacena correspondence to the logarithmic conformal field
theories. We study the correspondence between field theories in
(d+1)-dimensional AdS space and the d-dimensional logarithmic conformal field
theories in the boundary of . Using this correspondence, we get the
n-point functions of the corresponding logarithmic conformal field theory in
d-dimensions.Comment: 10 pages, LaTeX. A paragraph was added. To appear in Int. J. Mod.
Phys.
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
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
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
\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 BlĂŒmmel et al. (1997) to study differences in in vitro fermentation among lucerne silages inoculated with three microbial inoculants
Costos metabolicos de Engraulis ringens y Sardinops sagax en relacion al peso, temperatura y el nivel de actividad
El metabolismo estĂĄndar de la anchoveta es mĂĄs alto que el de la sardina; en .las larvas por un factor promedio de 2.3 y por 2.1 en juveniles y adultos en el rango de temperaturas de 14-20ÂșC. Lo opuesto sucede en el metabolismo activo: para una velocidad de nataciĂłn de un cuerpo por segundo( =metabolismo de rutina), la anchoveta adulta con un peso mayor de 20 g a 20ÂșC y mayor de 50 g a 14ÂșC gasta menos energĂa que la sardina de tamaños similares; incrementĂĄndose la velocidad a 3 c.p .seg a 17°C.todos los tamaños mayores de 1.5 g de Sardina necesitan mĂĄs energĂa que las anchovetas de pesos similares (una sardina de 5 g 1.5 veces y una de 25 g 3.8 veces mĂĄs).
Un cambio de temperatura de 6Âșc (de 14° C a 20°c) afecta a ambas especies en una forma diferente : asumiendo una velocidad de nataciĂłn de 1 cuerpo por segundo, una larva de anchoveta(
0.1 g) tiene que incrementar sus gastos metabĂłlicos dos veces mĂĄs que la larva de sardina, pero una anchoveta adulta( 40 g)necesita solo un 60% de lo que requiere una sardina del mismo tamaño .ABSTRACT: The stan,dard metabolism (calculated f or 14 ÂșC-20Âș.C) is higher f or anÂchovy than for sardine; for the larvae by an average factor of 2.3 and by a factor of 2.1 for juveniles and adults. The contrary occurs with the active metabolism: for a swimming speed of 1 body length per second (=routine .metabolism) an adult anchovy (bigger than 20 g at 20ÂșC and bigger than 50 g at 14°C) requires less energy than a sardine of the same. size. Increasing the swimming speed to 3 body lengths per second, at 17°C, all sardines bigger than 1.5 g require more energy than anchovy (a sardine of 5 g by a factor of .1.5 and one of 25 g. by a factor of 3.8)
A temperature changĂ© of 6.ÂșC (from âąl4ÂșC to. 20ÂșC) affects both species in a differĂ©nt way; assuming a swimming speed of 1 body length per second an anchovy larva (0.1 g) has to increase its metabolic expenditure twice as much as a sĂĄrdine larva but and adult ancbovy (40 g) needs just 60% of that of a sardine of the same size.BoletĂn IMARPE vol.7, nÂș3, 1983; p. 52-68IMARP
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