In the present study, a novel approach for mid-infrared (IR)-based prediction of bovine milk fatty acid composition is introduced. A rapid, solvent-free, two-step centrifugation method was applied in order to obtain representative milk fat fractions. IR spectra of pure milk lipids were recorded with attenuated total reflection Fourier-transform infrared (ATR-FT-IR) spectroscopy. Comparison to the IR transmission spectra of whole milk revealed a higher amount of significant spectral information for fatty acid analysis. Partial least squares (PLS) regression models were calculated to relate the IR spectra to gas chromatography/mass spectrometry (GC/MS) reference values, providing particularly good predictions for fatty acid sum parameters as well as for the following individual fatty acids: C10:0 (R2P = 0.99), C12:0 (R2P = 0.97), C14:0 (R2P = 0.88), C16:0 (R2P = 0.81), C18:0 (R2P = 0.93), and C18:1cis (R2P = 0.95). The IR wavenumber ranges for the individual regression models were optimized and validated by calculation of the PLS selectivity ratio. Based on a set of 45 milk samples, the obtained PLS figures of merit are significantly better than those reported in literature using whole milk transmission spectra and larger datasets. In this context, direct IR measurement of the milk fat fraction inherently eliminates covariation structures between fatty acids and total fat content, which poses a common problem in IR-based milk fat profiling. The combination of solvent-free lipid separation and ATR-FT-IR spectroscopy represents a novel approach for fast fatty acid prediction, with the potential for high-throughput application in routine lab operation.

The main aim of the present study was to find differences in the content of fatty acids and variations in elemental composition in beef samples of longissimus dorsi muscle related to cattle age and gender. A further goal was to describe interrelations among the selected variables (descriptors) characterising the samples. For this purpose, an extensive data table was compiled, which contains chemical descriptors specifying forty-six beef samples originating from four well-known Austrian grassland-based beef labels. The following descriptors were investigated: (a) concentrations of 33 fatty acids, (b) concentrations of 19 elements, (c) contents of dry-mass, protein, intramuscular fat, and ash, (d) total content of saturated fatty acids (SFA), mono-unsaturated fatty acids (MUFA), and poly-unsaturated fatty acids (PUFA), (e) total contents of omega-3 (n-3) and omega-6 (n-6) PUFA and their ratio. The correlation analysis provided a number of statistically significant correlations among the descriptors, which were concordant with the results of the principal component analysis and cluster analysis. Furthermore, the effect of age and gender of cattle (both acting as target factors) on the fatty acid content and elemental composition of beef was examined by analysis of variance (ANOVA) and appropriate non-parametric tests. Several important interrelations among the beef characteristics investigated were also discovered. Finally, the most relevant beef descriptors were utilised in linear discrimination analysis (LDA) for predicting the slaughter age of the cattle for beef authentication.

Economical and ecological issues as well as consumer demand for sustainably produced agricultural food rise the trends to fatten beef cattle on pasture during the grazing season. However, particularly for mountainous regions, implications of turning beef cattle on pasture remain unclear concerning animal performance and product quality. Therefore, the present study was conducted to compare short grass grazing with a semi-intensive indoor fattening system in the Alps. Charolais × Simmental heifers of about 300 kg live weight were either fattened on continuous pasture (3-5 cm sward height) and finished in barn (Pasture group) or solely raised in barn on a grass silage-based diet with 2 kg concentrates (Indoor group). Animals were slaughtered at 550 kg live weight. Results showed that continuous pasture with a finishing period in barn allowed as good growth and carcass performance as fattening in barn. Over the whole experiment, average daily gain was 993 g/day in the Pasture group and 1026 g/day in the Indoor group. During the growing period, daily gain was numerically lower in the Pasture group than in the Indoor group (767 g and 936 g, respectively). Carcass fatness of pasture fed animals was lower but within the desirable threshold. Water holding capacity, meat colour, and shear force, an indicator for beef tenderness, were unaffected by feeding practices, but fat colour was more yellow in the Pasture group. Furthermore, meat from animals fattened on pasture had lower intramuscular fat contents and enhanced proportions of nutritionally valuable omega-3 fatty acids and conjugated linoleic acids.

The literature implicates strongly that including energy supplements in dairy rations based on protein-rich forages increases performance and feed efficiency due to an improved and more balanced ruminal energy and protein supply. Therefore, both conventional and organic dairy farms primarily supplement roughages with concentrates, containing high proportions of cereal grains. However, considering the main principles of sustainable agricultural systems and nutrient cycles, the question of alternatives is raised. Therefore, the present study was conducted to compare grain and maize silage as energy sources in organic dairy cow rations. Two grass-clover silage-based diets, offered on an ad libitum basis, were supplemented either with 1 kg grain mixture plus 0.5 kg hay (treatment group G) or 2.1 kg maize silage (treatment group M) on a dry matter (DM) basis. The trial was carried out as a change-over design and lasted for 15 weeks. Intake of concentrates, DM and utilizable crude protein in the duodenum (uCP) were similar in both treatments. However, significant differences between treatments G and M were found for grass-clover silage dry matter intake (DMI) (13.4 versus 12.9 kg), forage DMI (14.6 versus 15.7 kg), crude protein (CP) intake (2885 versus 2801 g), ruminal nitrogen balance (RNB) (40 versus 29 g) and intake of neutral detergent fiber (NDF) (7630 versus 7900 g). Milk yield was not affected by treatment, but in treatment M, milk fat content was at 42.4 g kg -1 , significantly higher, and milk urea concentration at 19.7 mg 100 ml -1 , significantly lower, as compared with treatment G. Efficiency of N use (N in milk in % of N intake) tended to be improved in treatment M. Balances of energy and uCP (intake as a percentage of requirements) were unaffected by treatment.

The present study indicates a potential to reduce levels of concentrates and substitute them with maize silage in organic dairy cow rations at least in the second half of lactation. Copyright © 2007 Society of Chemical Industry.