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Mineral metabolism in young beef cattle during the period of changing from winter feed rations to grazing
Ist Teil von
Veterinární medicína, 1995-03, Vol.40 (3), p.65
Ort / Verlag
Czech Republic
Erscheinungsjahr
1995
Quelle
MEDLINE
Beschreibungen/Notizen
Concentrations of calcium, inorganic phosphorus, magnesium, sodium and potassium were observed in the blood serum of beef bullocks after their transfer from winter feed ration to grazing and in the successive grazing cycles within two years. Blood samples were taken by puncture from the vena jugularis from the identical six bullocks. In the first year of observation, blood collection took place a week before transfer to grazing while in the second year of observation twice in weekly intervals before grazing. In the period of grazing, the biological material was sampled in weekly intervals from week 1 to week 5 (May--Ist cycle, June--IInd cycle), then in week 10 (July--IIIrd cycle) and in week 14 (August--IVth cycle of grazing). Calcium concentrations in the blood serum of beef bullocks (Fig. 1) decreased after transfer from stable feeding to grazing while this drop was significant in the second year of observation (P < 0.05). That period was followed by an increase in serum calcium concentrations in both target groups. The concentrations of inorganic phosphorus in the serum of beef bullocks (Fig. 2) dropped after transfer to grazing but a gradual increase in the values was recorded in week 4 in the first year of observation and in week 5 of grazing in the 2nd year of observation. These changes were not statistically significant. The concentrations of serum magnesium in beef bullocks (Fig. 3) statistically significantly dropped (P < 0.05) after transfer from stable feeding to grazing in week 3 in the first year of observation and in week 4 of grazing in the second year of observation.