Dry Matter Intake Explained
When you compare a bag of concentrate, a bale of hay and a load of silage, the price tag alone can mislead you. Dry matter is the part of the feed that is not water — and dry matter intake is how much of that nutritious portion your animals actually eat each day.
What is dry matter intake and why does it matter?
Dry matter (DM) is feed weight minus water. Dry matter intake is how many kilograms of DM an animal eats per day — often 2.5% to 3% of body weight for cattle on good rations. Comparing feeds on DM basis shows true cost per nutrient. Use the feed value calculator for bags and the hay bale calculator for winter roughage planning.
What is dry matter?
Fresh grass, silage and wet brewers grains contain a lot of water. Dry matter is what remains when that moisture is removed. A feed analysed at 90% dry matter is mostly nutrients; silage at 35% dry matter is mostly water by weight.
Crude protein, energy and minerals on a feed label are usually reported on a dry matter basis. That lets you compare apples with apples — but you still buy and haul feed by the kilogram as-fed, including water.
Why dry matter intake matters
Animals have a physical limit to how much dry matter they can eat in a day. Cattle on high-quality pasture or finishing rations might eat 2.5% to 3% of body weight as dry matter. Sheep and goats often eat a higher percentage because they are smaller, but total kilograms per head are lower.
If dry matter intake is too low, animals cannot meet energy needs even if the ration looks good on paper. If intake is high but feed quality is poor, you pay to move bulk without gaining weight efficiently.
Using dry matter in farm planning
- Comparing bags: A cheaper bag with lower dry matter or protein may cost more per kilogram of actual nutrient.
- Wet feeds: Silage and wet by-products must be converted to dry matter before you compare them to hay or concentrate.
- Winter feeding: When veld quality drops, farmers often increase supplement or hay. Plan dry matter from all sources so animals do not fall short on energy.
- Feedlot rations: Intake is often expressed as a percentage of live weight. Small changes in that percentage change total tons bought for the batch.
Example: two bags, different dry matter
Bag A costs R420 for 40 kg at 88% dry matter. Bag B costs R390 for 40 kg at 82% dry matter. Bag A looks more expensive, but it delivers more dry matter and often more protein per rand when you run the comparison properly.
Use the Feed Value Calculator to line up dry matter, crude protein and bag price side by side.
Check against farm records
Lab analyses, feed tags and supplier spec sheets are your best source for dry matter percentage. Weigh what goes into troughs and what is refused if you want to refine intake on your own farm. Planning figures should be updated when you change supplier or season.
Frequently asked questions
What is dry matter in animal feed?
Dry matter is the portion of feed left after water is removed. A 40 kg bag at 88% dry matter contains about 35 kg of actual nutrients; silage at 35% dry matter is mostly water by weight.
How much dry matter do cattle eat per day?
Finishing cattle on quality rations often eat 2.5% to 3% of body weight as dry matter per day. Sheep and goats eat a higher percentage of body weight but smaller total kilograms per head.
Why compare feeds on a dry matter basis?
Price per bag ignores moisture differences. Converting to cost per kilogram of dry matter and crude protein shows which product delivers more nutrition per rand.
How do you plan dry matter intake for silage and hay?
Convert wet feeds to dry matter using the analysis percentage, then add dry matter from all sources — veld, hay, silage and concentrate — so total intake meets energy needs.
These guides and calculators are planning tools only. Check results against your farm records, feed labels, supplier prices and professional advice from your nutritionist, veterinarian or financial adviser where needed.