EFFECT OF DIFFERENT LEVELS OF DIETARY CALCIUM ON THE MINERAL AVAILABILITY IN CROSS BRED DAIRY CATTLE

A study for a period of 4 month was conducted to assess the effect of different levels of dietary calcium on mineral availability in cross bred dairy cattle. Twelve healthy cross bred dairy cattle in the last month of pregnancy were selected and divided in to two groups as uniformly as possible and allotted to two dietary treatments viz T1 (control ration where in the compounded cattle feed contained 0.5 per cent calcium as per IS (1992) standards and T2 (experimental ration) where in the compounded cattle feed contained 1.0 per cent calcium. Paddy straw was the sole roughage source in both the rations. All experimental animals were fed as per ICAR (1999) standards except for dietary calcium. A metabolism trial was conducted in the first month of lactation to study the balance of minerals. The results for calcium and magnesium balance differed significantly(p<0.05)between the two groups. Higher retention values were recorded in gp II for Ca and gp I for Mg. The results with respect to P and Zn did not differ significantly. The results suggest that the levels of Ca in compounded cattle feed at one per cent is better than 0.5 per cent to avoid negative balance of calcium during early lactation, when paddy straw is the sole roughage source. The study also indicates that with the high levels of Ca there is need for Mg supplementation to avoid negative balance arising due to interaction of the two elements.