Knowledge

The technical terms from ration calculation, briefly explained, so that the table above becomes readable.

Crude fibre (CF): The indigestible structural part of the feed. It supplies barely any energy, but it determines how long a horse chews and how full it feels. In ration calculation, crude fibre is therefore a fill target, not a nutrient requirement.
MJ ME: Megajoules of metabolisable energy: The share of the feed energy the horse can actually use. A 500 kg horse needs around 55 MJ ME a day at rest.
dvRP: Small-intestine-digestible crude protein, the protein that really gets through. Too little costs muscle; too much over a long period puts a strain on the liver and kidneys.
Fresh matter (FM): The feed as it is weighed, water included. Analysis values per kg of fresh matter can be multiplied directly by the amount fed, unlike values per kg of dry matter.
Dry matter (DM): What is left once the water is taken out. Hay is around 86 %, haylage 65 %, fresh grass just under 20 %. Dry matter intake should not fall below 1.5 % of body weight.
Appetite limit: The amount of forage a horse wants to eat in 24 hours, expressed as crude fibre. It is individual and it can be measured: Offer weighed hay over six hours, weigh back what is left, scale up to sixteen hours.
Maintenance requirement: What a horse needs to hold its weight, without work. Everything on top of that is added as an allowance: Housing, weather, stress, work.
Ideal weight: The weight the ration calculation aims at. The requirement is always calculated from the ideal weight, never from the current one, otherwise you feed the excess weight along with the horse.
Ca:P ratio: Calcium and phosphorus compete for absorption. The ratio should lie between 1.4 : 1 and 2 : 1. A calcium surplus is considerably more harmless than a phosphorus surplus.
EMS: Equine metabolic syndrome: Insulin resistance with fat deposits on the crest and over the quarters, and a high risk of laminitis. Starch and sugar have to be strictly limited, while crude fibre can be used to the full.
Obesity grade III–IV: Markedly to extremely overweight, with hard pads of fat. At this level, being overweight is no longer a question of looks but of health.