The benefits of feeding salt to livestock was first demonstrated experimentally in 1847. Years later sodium was identified as the primary component that influenced animal production. In the past 50 years economic benefit has been demonstrated in New Zealand and overseas by adding salt to fertilizer, supplementing with loose salt in feed and as a drench, and offering salt in salt lick blocks.
The video clip below demonstrates the benefits of a salt block placed in the paddock with a herd of cows. Positioned near their water trough the cows choose to lick the block of their own free will and in doing so are supplementing their diet with sodium and other trace minerals.