Five metabolism trials were conducted with 15 mature Friesian calves (3 in each treatment) to determine some mineral balances after being fed on different forms of sugar beet tops. The animals were fed: sun dried sugar beet tops (T1), shade- dried sugar beet tops (T2), sugar beet tops silage without additives (T3), sugar beet Lops silage with urea plus El-mufeed (T4) and sugar beet tops silage with poultry litter plus El-mufeed (TS). The mineral contents of 11 varieties of fresh sugar beet tops were investigated also. The results could be summarized as follows:
The ash and some macro and micro elements contents of the studied varieties of sugar beet tops on DM basis were relatively high. The ash content ranged between 20.44 and 31.44% and oxalate ranged between 3.30 and 4.89%, Ca, P, Na, K contents ranged between 5.84 and 8.0: 1.14 and 2.50; 3.48 and 5.15; 30.0 and 42.0 g/kg, also, Fe, Zn and Mn concentration ranged between 68 and 193; 28 and 117 and 19 and 56 ppm, respectively.
Calcium and P absorption and retention in the 5th treatment was higher than those fed the other dietary treatments. Potassium retention increased from 0.05 to 132.3 g/day by increasing K intake (from 128.2 to 177.9 g/day) when calves were fed different form of sugar beet tops: sodium was positive balance lot T1 T4 and T5 but 12t, 2nd 3rd treatments recorded a negative Na balance.
The average daily intake of Zn was similar T1, T2 and T3. Zine absorption and retention an above treatment, had the same trend and in a positive side On the het hand the calves in the 4th and 5th treatments showed a negative Zn balance although they consumed daily more 70 than other calves.
Iron intake Was in great excess of requirement for all calves. The difference between treatments was significant (540.6 to 808.5 mg/day/animal) but the differences between Fe absorption and retention were not significant as affected by its different levels in diet.