Pick up two bales of hay. Same colour, same sweet smell, same price. One can hold twice as much sugar as the other, and you would never know by looking at it. Colour and smell tell you something about how hay was made and stored. They tell you nothing about sugar, protein or energy.
That is what a lab analysis is for. It turns a bale into numbers. The numbers only help, though, if you know how to read them. This guide walks through a typical report, line by line.
Why It Matters More Than You Think
Forage is not a side dish. A horse eats roughly 1.5 to 2% of its bodyweight in forage dry matter every day, so for most horses hay is the largest part of the diet by far. A small difference in sugar or protein, multiplied by 8 to 10 kg a day, becomes a big difference over a month.
For some horses it is more than a detail. Horses with EMS, laminitis, PSSM or Cushing's need forage that is low in sugar. Sport horses and growing youngsters need enough protein. Easy keepers need fewer calories, not less chewing. You can only make those choices if you know what is in the hay.
Why This Matters Even More in Portugal and Spain
Whether you keep one Lusitano at home or run a busy competition yard, three things make hay quality extra important here.
- Hay is the diet for most of the year. In large parts of Portugal and Spain, pasture dries out during the long, hot summer, so many horses rely on hay almost all year round.
- Iberian horses can be sensitive to sugar. The same ECEIM consensus mentions research in which Andalusian horses (Pura Raza Española) showed lower insulin sensitivity than Standardbreds. Many easy-keeping Iberian horses do best on low-sugar hay.
- Quality varies. Hay quality changes from field to field and from cut to cut, and looks and smell only tell part of the story. When an analysis is available, it is worth reading it closely.
Start at the Top: Dry Matter
Every report starts with dry matter (DM): what is left when all the water is removed. Good hay usually sits around 85 to 90% DM. Typical value for our French Meadow Hay: 88%.
Most other values are given "on a dry matter basis". That makes hays comparable, whatever their moisture. It also means you convert when you feed: 9 kg of hay at 88% DM is about 7.9 kg of dry matter.
Sugar: Look for NSC
NSC (non-structural carbohydrates) is sugar plus starch. It is the number that matters most for sensitive horses. For horses with insulin problems (EMS), the European veterinary consensus recommends hay with NSC below 10% of dry matter. Your vet can tell you what fits your horse.
For comparison, our Meadow Hay typically comes in around 4.5% sugar. Our Longchamp® typically sits around 10.2%, which makes it a great forage for horses in work, and less suitable as the only hay for a sugar-sensitive horse.
Protein: Enough, Not Too Much
Crude protein (CP) tells you how much protein the hay contains. An adult horse in light work is often well covered by hay with around 8 to 10% CP. Horses in harder work, broodmares and youngsters need more.
Typical values: our Meadow Hay 8.1%, Longchamp® 11.6%. Alfalfa sits much higher at 18.4%, which is why it works best as a small top-up rather than the whole ration.
Fibre: NDF, ADF and Lignin
Fibre is what keeps a horse's gut busy and healthy, but not all fibre is equal.
- NDF is the total fibre (the cell walls). The higher it is, the more a horse chews and the less it tends to eat.
- ADF is the less digestible part of that fibre. Higher ADF usually means less energy.
- Lignin (ADL) is the woody part that horses can hardly digest at all.
Typical values for our Meadow Hay: NDF 62%, ADF 41%, lignin 4.8%. Plenty of fibre to chew on, with a moderate energy value.
Energy: DE in Mcal
Digestible energy (DE) is given in Mcal per kg of dry matter. It is often calculated from ADF and protein, using the equation from the National Research Council (2007). Typical values calculated this way: Meadow Hay 1.86, Longchamp® 2.04, Alfalfa 2.35 Mcal per kg DM.
A tip: if your horse is gaining weight on hay alone, look at DE and NSC before you cut the amount of hay. A lower-energy hay is usually the better answer than less forage.
Minerals: The Calcium to Phosphorus Ratio
Horses need more calcium than phosphorus. A ratio between 1.5 and 2 to 1 is the usual norm. Our Meadow Hay typically sits around 1.9 to 1. Alfalfa is much higher at around 5 to 1, which is fine because it is fed in small amounts on top of a base hay.
Read the Small Print
- Who analysed it? Look for an independent laboratory, ideally accredited.
- Which method? NIRS is fast and widely used. Wet chemistry is the reference method.
- When, and which report? A date and a report number show the analysis belongs to a real, recent sample.
And remember: an analysis describes a sample. Natural forage varies from harvest to harvest, so treat the numbers as a reliable guide, not a guarantee for every single bale.
A Quick Checklist
- Is the report on a dry matter basis, and what is the DM?
- What is the NSC, and does it suit your horse?
- Is the crude protein enough for the work your horse does?
- How much fibre (NDF), and how much energy (DE)?
- Is the Ca to P ratio between 1.5 and 2 to 1?
- Who analysed it, when, and with which method?
From Numbers to a Daily Plan
We use independent lab analyses when selecting our forages. Want to turn hay values into a daily plan for your horse? Our feeding calculator does the maths for you, using typical values for our hay.
Sources: National Research Council (2007), Nutrient Requirements of Horses; Durham et al. (2019), ECEIM consensus statement on equine metabolic syndrome, J Vet Intern Med.