Analysis of Silage Fermentation Characteristics Using Transflectance Measurements by Near Infrared Spectroscopy

The fermentation end products as lactic acid, volatile fatty acids and ammonia-nitrogen, are important indicators of the efficiency of silage fermentation and are closely related to nutritive value of them (Jaster, 1995). Drying is problematic in the case of silage as many fermentation products are volatile and may get lost during the drying process. This may be a reason why NIR technology is being little used for the evaluation of silage fermentation characteristics. The feasibility of using near infrared transflectance spectroscopy to evaluate the content in fermentation end products of grass and maize fresh silage was investigated in this study

Feeding with Badly Preserved Silages and Occurrence of Subclinical Ketosis in Dairy Cows

Ketosis in dairy cows is due to high levels of circulating ketone bodies in blood (Duffiel, 2000). In early lactation, the capacity of voluntary dry matter intake does not allow dairy cows to cover the total energy requirements for maintenance and production, and then the body reserves are mobilised. However, the amounts of fatty acids that can be metabolised in the liver are limited, later they are converted to ketone bodies (Tveit et al., 1992). During forage ensiling, acetic and lactic fermentations only are desirable, but frequently butyric and alcoholic fermentations appear. When the animals ingest these silages, the butyric acid is metabolised to ketone bodies (Chalupa, 1974). The ketosis problems could be due to both causes simultaneously. The objective of this paper was to establish the incidence of subclinical ketosis in dairy herds of Asturias (Spain) and its relationship with the nutritive and fermentative characteristics of silages used in the ration

Crystallographic and computational study of t-butyl N-[3-hydroxy-1-phenyl-4-(pyridin- 2-ylsulfanyl)butan-2-yl]carbamate and its pyrimidin-2-yl analogue

Abstract The crystal structure analysis of the biologically-relevant title compound (1) shows the carbonyl-O2 and amide-H atoms to be anti, and perpendicular relationships between the carbamate residue and the pyridyl ring [dihedral angle=84.60(10)°] and between the carbamate and aryl ring [74.84(11)°]; the rings are approximately co-planar [12.07(17)°]. An intramolecular hydroxyl-O–H···N(pyridyl) hydrogen bond that closes a S(7) loop is noted. Of interest is the observation that this hydrogen bond is not found in the structure of the pyrimidinyl analogue (2) which was characterised as a monohydrate, i.e. 2·H2O, in an earlier study. Density-functional theory calculations show the observed conformation in 1 is 2.0 kcal/mol more stable than the conformation where the intramolecular hydrogen bond is absent. This energy difference reduces to ca 0.5 kcal/mol in the case of 2. The differences in molecular conformations found for 1 and 2 are therefore ascribed to the dictates of overall molecular packing, in particular due to the influence of lattice water in 2·H2O.</jats:p