Supplement forage with forage

You can actually supplement forage with forage! This can be really useful in stables where you have horses with different energy and protein requirements. You buy a “basic forage” that suits the horses with lower energy and protein requirements. Then you spend money on a “supplement forage” with high energy and protein values. It is also possible to do the opposite, supplement with straw to be able to increase the forage ration with kg DM (dry matter) per day and still keep down the energy and protein intake.
Here are two examples, one where we supplement with an energy and protein rich forage and one where we supplement with straw.
Here are our horses for these example:
Horse, 500 kg, normal keeper, does hard exercise
Total energy requirement per day (maintenance + exercise) → 98 MJ metabolizable energy
Total protein requirement per day (6 g digestible cp/MJ) → 588 g digestible crude protein
Feed ration
Basic forage: 8.3 MJ ME/kg DM 45 g digestible cp/kg DM
Supplement forage: 11.5 MJ ME/kg DM 95 g digestible cp/kg DM
Rations
Basic forage: 6 kg DM/day 6 × 8.3 = 49.8 MJ ME 6 × 45 = 270 g digestible cp
Supplement forage: 4.5 kg DM/day 4.5 × 11.5 = 51.8 MJ ME 4.5 × 95 = 428 g digestible cp
Total 101.6 MJ ME per day 698 g digestible cp per day
→ gives in total 2.1 kg DM forage/100 kg body weight and day
Pony, 350 kg, easy keeper, does medium exercise
Total energy requirement per day (maintenance + exercise) → 61 MJ metabolizable energy
Total protein requirement per day (6 g digestible cp/MJ) → 364 g digestible crude protein
Feed ration
Basic forage: 8.6 MJ ME/kg DM 65 g digestible cp/kg DM
Cereal straw: 6.3 MJ ME/kg DM 0 g digestible cp/kg DM
Rations
Basic forage: 6 kg DM/day 6 × 8.6 = 51.6 MJ ME 6 × 65 = 390 g digestible cp
Cereal straw: 2 kg DM/day 2 × 6.3 = 12.6 MJ ME 2 × 0 = 0 g digestible cp
Total 64.2 MJ ME per day 390 g digestible cp per day
→ gives in total 2.3 kg DM forage/100 kg body weight and day
Also remember to make sure the horse will get enough minerals and salt.
When you are weighing up the feed ration you might need to calculate from kg DM to kg forage. Here you find more information on kg feed and kg DM and examples of calculations!
Sara Muhonen, AgrD