Purina Mini Feed isn't available in Canada (and from what I can glean, won't be) You should be able to get the nutritional breakdown off the Purina website and take it in to your local feedstore....they'll be able to tell you what products they carry that are comparable. Lots of the feed manufacturers are starting to jump on the band wagon of providing products specifically designed for 'easy-keepers'/overweight/metabolic syndrome type horses & ponies. Purina isn't the only one anymore...just the only one who seems to advertise in the AMHA magazine ;-)
Hope that helps!