Abstract:
The quality of feed is very
important in dairy milk production. The
aim of the current paper was a
comparative characterisation in terms of
crude chemical composition, Ca and P,
heavy metals (Pb, Cd, Zn, Cu), nitrates,
nitrites and pesticides, for the natural
meadow and green alfalfa, cultivated in
ecological and conventional systems,
utilised for feeding dairy cows. Sampling
and analysis were performed according to
established standards and working
methods: drying for dry matter (DM);
calcination for crude ash (C Ash);
Kjeldahl method for crude protein (CP);
Soxhlet method for crude fat or ether
extract (EE), spectrophotometry for P,
nitrates and nitrites; atomic absorption
spectrometry for Ca, Pb, Cd, Cu and Zn;
gas-chromatography for pesticides. For
alfalfa, the highest values in the
ecological system were for C Ash
(12.68%), EE (2.50%), NFE (35.78%)
and Ca (1.79%). For the natural meadow,
the highest values in the ecological
system were for DM (25.72%), OS
(89.32%), EE (2.76%), NFE (45.27%)
and Ca (0.70%). The toxic heavy metal
content was below the limits allowed
(1 mg/kg Cd and 30 mg/kg Pb). For Pb
the values determined from the two feeds
were between 0.06 mg/kg and 0.16 mg/kg
and for Cd between 0.007 mg/kg and
0.02 mg/kg. The pesticides residuum was
under the detection limit of 0.05 mg/kg
DM for organo-chlorinated pesticides and
0.001 mg/kg for organo-phosphoric
pesticides. All the studied forages were
safe regarding pollutants (heavy metals,
nitrites, nitrates and pesticides), but
statistical differences existed between the
production systems, such that the
ecological system seems to be better.
