Acer spp Chilean corralero horse NEFA Standardbred trotters alfalfa behaviour biodiversity colic crude protein dairy equine chain dairy equine management and feeding domestic biodiversity environment equine equine and equestrian tourism equine atypical myopathy equine grazing equine milk equine work exclosures eyelid twitches faecal water syndrome feed changes feed intake feeding feeding practices fiber fibre flax seed forage maturity