I can't help with the mineral block, though maybe if you have access to seaweed you could put a bit of that out? But, here is a story (and perhaps a preview of an animation film, Babe and the Bullock) Babe, one of our Kunekune sows and Sydney, one of my neighbour's bullocks became very attached to each other. Babe would take the gates off their hinges to seek him out. I thought at first that she was looking for the boar but it became clear that Sydney was her intention.
Having sorted the gates the bullock came looking for Babe. He would break through the hedge and set off at a gallop, hurdling stock fencing like a champion race horse. Once together they would settle down to graze and lie back to back contentedly.
The bullock went to market, Babe moped for a few days but seems to have got over her broken heart.
So, this, I know is a one off but animals do find friendship in the oddest ways.