Richard Lab:Review of gaseous emissions from silages

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Reference	Information extracted	type of silage (grass, grain, additives)	output data (gas emissions)
Porter, M. G. , Murray, R. S. 2001. The volatility of components of grass silage on oven drying and the inter-relationship between dry-matter content estimated by different analytical methods Grass and Forage Science 56 (4), 405–411.	Upon oven drying some grass dry matter is volatilized. True DM (dry matter) content is one that's corrected for the volatilization amount, based on volatilization coefficients. This study can be used to learn of the main VOC (volatile organic acids) that are emitted from grass silages, and the relative proportions in which they are emitted. The table below shows the grass silage's content in ammonia, alcohols, and 4 volatile acids.Lactic acid volatility coeffcients at 60°C, 85°C and 100°C were 0.090, 0.224 and 0.375. Volatile fatty acid volatility coeffcients at 60°C, 85°C and 100°C were 0.554, 0.716 and 0.892. The volatilities of ammonia and total alcohols were not temperature dependent. Absolute dry matter (GCDM), alcohol-corrected toluene dry matter (ATDM) and volatile-corrected oven dry matter (VCODM) contents based on drying temperatures of 100, 85 and 60 deg C. Silage dry matter in western Europe ranges from 153 to 365 g / kg (oven dry-matter content at 100°C). Gas-liquid chromatography was used to determine the amount of volatile fatty acids in liquid silage extracts volatile compound g / kg fresh silage % out of fresh silage content in VOC lactic acid 23.390 76.493 acetic acid 3.690 12.068 total alcohols 2.400 7.849 ammonia 0.498 1.628 n-butyric acid 0.400 1.308 propionic acid 0.200 0.654
PORTER M.G. (1992) Comparison of sample preparationmethods for the determination of gross energy concentration of fresh silage. Animal Feed Science Technology, 37, 201-208.	Silage is prepared for analysis by chopping 2 kg-samples.	.	.
STEEN R.W.J. (1989) A comparison of soya-bean, sunflower, and (r)sh meals as protein supplements for yearling cattle offered grass silage based diets. Animal Production, 48, 127-132.	4 reps of each silage sample are analyzed for pH, ammonia and nitrogen concentrations, toluene dry-matter content (TDM), by the methods described by Steen (1989),	.	.
PORTER M.G. and BARTON D. (1997) A comparison of methods for the determination of dry-matter in grass silage including an extraction method for water. Animal Feed Science Technology, 68, 67-76., and (r)sh meals as protein supplements for yearling cattle offered grass silage based diets. Animal Production, 48, 127-132.	silage samples are also analyzed for water content, to give an absolute dry-matter content (GCDM) according to the method of Porter and Barton (1997). Alcohol corrected toluene dry matter (ATDM) is considered to be the sum of toluene dry matter, ethanol and propanol.	.	.
Alister D. Muir and Bernard P. Goplen. Quantitative Reversed-Phase HPLC Analysis of Dicumarol in Sweetclover Hay and Silage Samples. J. Agric. Food Chem. 1992, 40, 820-823	HPLC is used to analyze liquid silage extract for Dicumarol. 1 g samples are extracted in 1,2-dichloroethane/phosphate buffer. The extract is purified through a silica column. Next, reversed-phase HPLC chromatography is performed using a sodium acetate/methanol(25:75) eluent, and UV wavelength of 303 nm for detection.	.	.
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