Fourteen sexually mature heads of cattle were divided into two groups; Group I receiving mineral mixture A, containing 15 % of Bolus alba, while Group II were given mixture B, containing no Bolus alba, but 10 % more Ca. Otherwise, both groups received the same feeding. Samples of blood and faeces of the animals were taken monthly for the determination of phosphorus, respectively phosphorus and carotenes. The experiment lasted one stabling period. In Group I, the mean inorganic phosphorus values of the blood were 6.7 mg/100 ml. and in Group 11, 6.1 mg/100 ml. The mean phosphorus values of the faeces were 8.8 gr/kg dry matter in Group I and in Group II, 9.3 gr/kg dry matter. The mean carotene values in Group I were 98.3 mg/kg dry matter and in Group II, 96.3 mg/kg dry matter. However, none of these differencies is statistically significant. On the basis of the present investigation it can be concluded that Bolus alba exerts no detrimental influence on the resorption of phosphorus and carotenes in the digestive tract of cattle
