Influence of Dietary Phosphorus Inadequacy on Concentration of Inorganic Phosphorus, Calcium, Magnesium in Plasma, Saliva and Rumen Liquor in Calves

The effect of dietary P inadequacy on concentrations of Pi, Ca, Mg in blood plasma, saliva and rumen liquor was studied in crossbred calves by feeding P adequate (3.41 g P/kg DM) and P-deficient (1.08 g P/kg DM) diets. The effect on salivary pH, ruminal pH, blood glucose, blood NH₃-N, haemoglobin and PCV were also studied. Dietary P-inadequacy did not influence salivary and ruminal pH while Pi level in plasma, saliva and rumen liquor reduced markedly. The Ca concentration in blood plasma, saliva and rumen liquor significantly (p<0.01) increased (10.36±0.41; 2.29±0.16 and 3.44±0.29mg/100 ml vs 13.16±0.45; 3.33±0.15 -and 10.89±0.59 mg/100 ml) whereas Mg levels remained unaffected in blood plasma and saliva but increased (P<0.01) in rumen liquor (5.33±0.40 vs 7.20±0.32 rng/100 ml) during P-inadequacy. Blood glucose concentration decreased while ammonia-N concentration tended to rise with decrease in plasma Pi levels. Haemoglobin and PCV levels remained unaffected during P-deficiency. Pica was noticed in 3 out of 4 calves under study.