feeding guidelines
When I teach the BHS stage courses alot of people find it difficult or mis-understand what they feed their horses in terms of the work they do, the levels of work would be as follows: Light work would be if you are riding twice a day for about an hour each time, perhaps schooling and then a hack. Medium work would be if your were doing novicey competition once to three times a week, and hard work would be professional riding/competing ie three day eventing or winter showjumping!
So if you are in light work (which most people are) the feeding should be as follows:
1. find out your horses weight - the best way to do this is to use a weigh tape (these can be bought from most good tack shops - or if you ring the feed companies, alot of the time they can give you one for free!) put the weigh tape around the horse (using the horse side) about where you would put the girth. Weighing your horse regulary is really important, as it can give you a good indication if anything is starting to go wrong as it may be causing their weight to drop off and you can catch it early. Also if you want to feed him up it will help you to keep track of the weight gain.
2. you want to feed between 1.5 - 3% of the horses body weight, so say for example your horse weighs 600kg & we want to feed him up this would be: 600/100= 6 6x2.5% (for normal feeding I would say 1.5 to 2%) = 15kg
so each day your TOTAL feed weight is 15kg.
3. You should always give your horse AT LEAST 2/3rds of it's feed in fibre format - especially if you want to bulk him up so: 15kg/3= 5kg 5kgx2= 10kg
so each day your horse gets 10kg pure fibre i.e. hay or haylage in a haynet and 5kg of feed.
4. You absolutely should feed your horse small quantities, I would say at least 3 feeds a day, and depending what you are doing with your horse give him the feed accordingly. Remember the horses' stomach is only about the size of a rugby ball, so huge feeds will only pass thorough his system without him being able to digest it. For example a hack in the morning and schooling in the afternoon, I would give 2kg feed in the morning, 2kg feed at lunchtime and 1kg in the evening (you don't want to feed loads when he's just going to stand in the stable!) that adds up to the 5kg of feed in your diet. to bulk up this 5kg could be mostly made of high fibre, and don't forget succulents which aid in saliva production and help digestion - all making your feed work better for your horse and his system get as much out of it as possible!
Remember to change his feed slowly, over a period of about 2-3weeks and you shouldn't have any problems.
hope this helps!