Jim hates speedibeet will not touch it but he loves normal sugarbeet. He picks out all the nuts and leaves the speedibeet. He has a bit of a sweet tooth and I think this is why he does not like it. My other horse does not care will eat either. Maybe try the normal sugarbeet?
have you just started feeding the speedibeet? if so introduce it gradually, only a small amount at a time.
but otherwise if hes always had it i wouldnt worry too much, Bloss sometimes goes for a week without totally finishing her 'tea', then she starts eating it again for no reason. cant explain it but shes always happy in herself so i never worry too much about it