Determination of marker chromic oxide in faeces of grazing goats on Mediterranean shrublands by AAS

The most widely used external indicator for feed intake evaluation of grazing animals is Cr2O3. In this paper the combination of Cr2O3 dissolution by alkali fusion (Na2O2) with its determination by atomic absorption spectrophotometry (AAS) has been examined. Faecal samples were collected from four 2-year-old, meat-type, female, local goats grazing in a Mediterranean type shrubland in Northern Greece, for 5 consecutive days. Each composited sample from every animal and day was analysed eight times. There was very high linear correlation (Y = 0.0024 + 0.01 X, r2 = 0.99) between absorbance (Y) (357.9 nm wavelength, 0.2 nm slit width) and Cr2O3 concentration (X). The repeatability and reproducibility of the method was very satisfactory (CV ranged from 2.7 to 7.6%). The proposed method seems to be simple, inexpensive and precise for routine determination of Cr2O3 in faeces of grazing animals in which Cr2O3 is used as a reference marker.