Show season is a time when horses spend more time on the trailer and in strange (to them) stalls. This can cause them stress and anxiety. This is another case of making sure they get sufficient forage, and forage of better quality.
When on the trailer they should have free access to top quality hay, hay that is palatable as well as nutritious, second cutting grass hay or an alfalfa mix would be good choices. You don’t want to be making big differences from their normal hay, so they should be getting the better hay even when at home.
Mashes (grain mixed with water) are a good thing to feed both before getting on the trailer and when they get off. Plenty of fiber both in the hay and mixed in with the grain helps them to digest and keeps things moving. In the grain feed, add in either some bran (what or oat bran), apple pomace or rice bran or sugar beet pulp. Feed as a wet mash. Add salt and maybe some molasses if they are reluctant to eat it.
As mentioned before, feed them this mixture at home as well as on the road, so that they are used to it. Depending on the discipline you do, will make a big difference in what you feed. Horses who do slow steady work need more fiber and less starch and sugar, their muscles are not going to be working hard enough to need it. If they have problems maintaining weight, add in a high fat source, such as flax or rice bran. Don’t feed extra sweet feed or grain, feed better quality hay and make sure they get all they can eat. Extra fat also helps them to have nice shiny coats.
Horses who work fast and hard, will need more starch and sugar, they still need high quality forage, but they do need extra calories and their muscles will be working harder and will consume the glucose from the starch and sugar. They are more likely to be sweating and hence will need electrolyte supplementation. Extra magnesium in the grain portion will both reduce anxiety and help to keep things moving along the GI tract. A high-quality protein supplement will help their muscles to recover from exertion. Addition of either a proprietary amino-acid mix or whey protein into the diet will be of benefit to these horses.
Keep an eye on water intake, especially if the weather is hot, make sure they have plenty of clean water available.