Top Tips – Forage Analysis, Understanding Dry Matter


When you go to the time, effort and expense of analysing the forage your horse eats, so that you can use a forage focussed approach to balance the minerals supplemented, the last thing you want is to find out that some of the key aspects determining the levels and quality of nutrients in your horse’s diet are missing.

The dry matter (DM) figure on a forage analysis report is crucial. Without it you cannot determine how much of each nutrient your horse will be eating in the total amount of forage consumed throughout a 24 hour period.

This article aims to help you understand why you should choose to purchase a report which shows the dry matter content of the forage you are testing.

Reported DM on a Horse Forage Analysis Report


The DM figure is vitally important when calculating the minerals required to create a balanced, forage focussed, supplement or the amount of protein available in a measured amount of forage.  Knowing actual amounts can help you optimise your horses diet to maintain and support equine health.  However, many of the reports available do not include this figure so it is worth checking this before you buy.

DM – equals and represents everything in the forage sample other than water including protein, fibre, fat, minerals, etc..

Horses consume the forage they are eating to meet their DM needs, because it is the dry matter that contains all of the nutrients. This means that a horse eating a 900 g/kg dry matter content hay will eat less than a haylage containing more water, and thus a lower dry matter content of say 700 g/kg. A wetter forage will cause the horse to consume more.

Dry Matter Content Analyse Horse Forage

Where a horse is eating grass at a dry matter content of only 200 g/kg then the horse will consume 4 and half more times volume of grass to get the same dry matter content as the hay with a DM content of 900 g/kg. Without knowing the dry matter content you can’t work out how much hay the horse might need to eat to fulfill dry matter needs.

There is a wide variation in the dry matter content of forages. The table below demonstrates these variations.

ForageDry Matter Range
Dry Matter Range
Hay800 g/kg920 g/kg
Haylage550 g/kg850 g/kg
Grass160 g/kg330 g/kg

Knowing the dry matter content of forage becomes vitally important where your horse is on a restricted supply of forage to control weight gain, or perhaps your horse receives a controlled amount of forage due to needing increased levels of concentrates because of heavy work load or being elderly.  Here a haylage fed at 10 kg with a dry matter content of 700 g/kg is going to give very different levels of, for example, protein, than 10 kg of hay fed with a dry matter content of 900 g/kg.  The table below gives some figures for protein and how the amount in a horse’s diet might be affected by the dry matter content of a dried forage such as hay or haylage.

10% Crude Protein Levels
(in 10 kg of forage)
As reported at 100% DMAs reported at DM level
Haylage DM 70%1000 grams700 grams
Hay DM 90%1000 grams900 grams

You can see that if a forage analysis does not report the dry matter content and the amounts are assumed to be 100% at 1000 g/kg, you have less nutrients than is at first apparent. If you are controlling the amount of forage fed to your horse, you may well end up feeding drastically lower amounts of all the nutrients including minerals.  Where a horse is sick or elderly these accurate calculations can really pay dividends in supporting good health.  So it pays to buy a mineral and nutritional report for your horse which includes the actual dry matter content of your forage.

All our forage analysis includes dry matter values, without this figure we could not accurately determine your horses needs.

Coming soon: why you need to make sure that iodine, selenium and chloride are reported on your equine forage analysis report.

Grass Forage Analysis for Horses