[Cobalt supply to ruminants, a bottleneck?].

On some dairy farms the supply of cobalt was expected to be adequate given the soil data and the composition of the ration. However cows on these farms produced less milk than expected and their condition was poor considering their ration and milk yield. The milk lactose content was less than 4.

[Necessity and method of administering minerals in cattle feed].

The soil of cattle farms can differ markedly, thus making it impossible to guarantee that animals receive an adequate supply of minerals. Mineral deficits are expected first in animals grazing pastures on sand, peat and iron-rich clay soils. The quality of the rations can also differ, which underlies the necessity of mineral supplementation.