A comparative assessment of the potential use of alginates and dietary calcium manipulation as countermeasures to reduce the transfer of radiostrontium to the milk of dairy animals

The potential of using different alginates or supplementary calcium as feed-additives to reduce the transfer of ingested radiostrontium to milk was assessed in dairy cattle fed a haylage/concentrate diet. The feed-additives compared were: calcium alginate (4% by dry matter), sodium alginate (4% by dry matter) and four levels of supplementation with CaCO3. Both alginates reduced the transfer of radiostrontium to milk by 30–40% without effecting diet palatability. However, the high present cost of alginates precludes their use as countermeasures. Dietary calcium supplementation reduced the transfer of 85Sr to milk broadly in agreement with previous predictions. From data relevant to dairy cattle in the United Kingdom it is suggested that dietary calcium intake could be doubled without exceeding recommended maximum intakes, thus decreasing the transfer of radiostrontium to milk by approximately 50%.