You should consider adding a vitamin/mineral supplement to your mini's diet when:
1) the mini is on an all hay and/or pasture diet. The all-forage diet may keep him fat enough, but will probably not supply a balanced array of vitamins and minerals
2) the mini is being fed a commercial feed, but LESS than the manufacturer recommends. In other words, if the feed instructions say "feed at .5% of body weight" and your mini weighs 200 lbs, then you would have to feed 1 lb of that feed per day in order to meet the guaranteed analysis for all the nutrients. If 1 lb of that feed makes your mini too fat, then you will probably decrease it. Once you decrease the feed to an amount that is LESS than the manufacturer recommends, you also decrease the nutrients provided and now your mini may not be getting its daily needs for vitamins and minerals (but his weight will be more appropriate).
3) the mini has special needs beyond what the feed and hay are providing. This might include a young growing horse being fed a food formulated for adults, a late stage or lactating broodmare that needs extra calcium and protein during this very stressful time, a hard working show horse who is undergoing the rigors of travel, etc.
Flipping through a catalogue like Jeffer's or Country Vet will make your head swim with supplement choices. There is no one size fits all as each horse's situation is unique. The most common scenario, however, is #2 -- where the mini is being fed less of a commercial feed than the manufacturer recommends. In this case, the addition of any general vitamin/mineral supplement, fed according to the manufacturer's instructions, will help boost the overall nutrient level of the reduced volume of feed. General vitamin/mineral supplements like Accel, Vita-Key, HorseGuard, etc. are all possible choices, but should be looked at carefully against what else you are feeding and the area of the country you live in. It is possible to over-supplement a few of the vitamins and minerals, like Vitamin A and selenium, so a careful inspection of the diet as a whole is recommended before choosing a supplement.
Robin C
