The aim of the paper was to examine the reliability of NIRS for estimating the concentration of net energy for lactation (NEL) in forages and to compare the results to those obtained on the basis of chemical composition and digestibility coefficients from German DLG tables. Separate NIRS equations for hay, grass silage and fresh forage and common equation for all forages were developed. The determination coefficient of cross validation (R2CV) and standard error of cross validation (SECV) for NIRS calibrations ranged from 0.81 to 0.89 and from 0.16 to 0.25 MJ NEL kg-1 dry matter (DM). NIRS estimates for samples from validation sets were much closer to corresponding in vitro values than the estimates based on digestibility coefficients from tables. In case of NIRS the average absolute individual deviations from in vitro values for hay, grass silage, fresh forage were 0.13, 0.20 and 0.16 while in case of DLG tables they were 0.29, 0.42 and 0.29 MJ NEL kg-1 DM. The reliability of NIRS calibration developed on pooled set of hay, grass silage and fresh forage samples was similar to those obtained on separate sets.
COBISS.SI-ID: 3964264
Five different procedures of estimation of energy value of forages were tested on the basis of independant validation test comprising samples of fresh forage (n=19), grass silages (n=6) and hay (n=1) with known in vivo assessed digestibilities. The following procedures were examined: A – regression equations which require components of Weende analyses and were developed on the basis of gas production obtained by the means of Hohenheim gas test (VP), B – direct NIRS calibrations for ME and NEL, which were developed on the basis of sample composition and VP, C – Weende analyses and NIRS calibrations for VP and acid detergent insoluble fibre (KDVOS), in second step calculation according to GfE (2008) equation, D - NIRS calibrations for Weende analysis, VP and KDVOS, in second step calculation according to GfE (2008) equation, E – Weende analyses and DLG tables. In vivo estimated NEL concentrations were in procedures A, B, C, D and E on average underestimated for 0.04 ± 0.36, 0.15 ± 0.34, 0.10 ± 0.32, 0.13 ± 0.29 and 0.13 ± 0.41 MJ NEL/kg dry matter. The lowest For laboratories where NIRS calibrations for gas production obtained by the means of Hohenheim gas test are not available regression equations for prediction of energy value on the basis of the results of Weende analyses were suggested. Equations are based on 303 samples for which the concentrations of ME and NEL were assessed on the basis of their composition and VP according to equation GfE (2008). It was found that these equations are more reliable than forage evaluation on the basis of chemical composition and DLG tables.
COBISS.SI-ID: 3953256
The aim of the study was to obtain information on the fermentation characteristics, nutritive value and 6 carotene concentration of yarrow (Achillea millefolium L.) silage harvested in summer 2010. The unwilted and wilted yarrow was ensiled in small-scale laboratory silos. Concentrations of net energy for lactation (NEL) and metabolizable energy (ME) were assessed on the basis of the amount of gas which was produced during the incubation of samples with rumen liquor in vitro. It was concluded that both silages were well fermented. Wilting of yarrow prior to ensiling is favourable from the point of concentration of WSC and restriction of proteolysis during the fermentation process, whilst ensiling of unwilted material enhances beta carotene preservation.
COBISS.SI-ID: 3869032