Dry Matter Intake Calculator
Estimate lb of dry matter a cow, heifer or steer will eat per day by class and forage quality, then scale it to your herd and your hay pile.
Your numbers
Dry pregnant cow, 1,200 lb, average forage
24.0 lb DM/head/day
- Herd total dry matter/day
- 1,200 lb
- As-fed lb/head/day
- 27.3 lb
- Tons as fed per 30 days (with waste)
- 22.5 tons
- This herd needs about 1,364 lb of as-fed forage per day, or roughly 22.5 tons per 30-day feeding period once storage and bunk waste are included.
- Add a cold weather adjustment for sustained wet or windy conditions below the animal's lower critical temperature.
- Book intake values are a starting ration budget. Confirm against actual bunk or feeder disappearance and body condition score over several weeks.
Show the math
- Intake as % of body weightDry pregnant cow on average forage = 2.0% of body weight
- Base dry matter intake1,200 lb × 2.0% = 24.0 lb DM/day
- Cold weather adjustment24.0 lb × (1 + 0%) = 24.0 lb DM/day
- Herd total dry matter24.0 lb × 50 head = 1,200 lb DM/day
- As-fed pounds at this forage moisture24.0 lb DM ÷ 88% DM = 27.3 lb as fed/head/day
- Tons as fed for 30 days, with waste1,364 lb × 30 days × (1 + 10% waste) ÷ 2,000 = 22.5 tons
Assumptions this calculator used
Nothing here is hidden. Change any figure you have better local data for.
Ring feeders run 6-15%; hay unrolled on the ground can run higher. Source: Oklahoma State University Extension hay feeding loss studies.
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How to calculate dry matter intake
Dry matter intake (DMI) is the foundation of every beef ration — it sets how much of any feed an animal can physically consume before you even get to balancing energy and protein. Intake capacity is usually expressed as a percentage of body weight, and that percentage moves with production stage and forage quality rather than staying fixed.
lb DM/day = body weight (lb) × intake % of BW
herd DM/day = lb DM/day × head count
as-fed lb/day = lb DM/day ÷ forage dry matter %
tons/30 days = as-fed lb/day × 30 × (1 + waste %) ÷ 2,000
Worked example
A 1,200 lb dry pregnant cow on average-quality hay (52-58% TDN) eats about 2.0% of body weight, or 24 lb of dry matter a day. At 88% dry matter, that is 27.3 lb of hay as fed per day. For a herd of 50 cows, total daily dry matter is 1,200 lb, or about 27.3 tons as fed over 30 days once a 10% feeding waste allowance is added.
Common mistakes
- Using one intake percentage for the whole herd. A lactating cow and a dry cow at the same weight do not eat the same amount — nursing a calf raises intake capacity substantially.
- Ignoring forage quality. Low-quality, high-fiber hay physically limits intake through gut fill even when the cow needs more energy, which is why thin cows on poor hay often cannot simply "eat more" to catch up.
- Skipping the as-fed conversion. A DMI figure means nothing at the hay ring until it is divided by the forage's actual dry matter percentage from a forage test.
- Forgetting feeding waste. Ring feeders alone still lose 6-15% of hay to trampling and weathering; unrolling on the ground can lose much more.
Dry matter intake as % of body weight, by class and forage quality
Approximate lb DM/head/day intake capacity as a percentage of body weight. Actual intake varies with body condition, weather, water access and feed presentation.
| Class/stage | Low quality (<52% TDN) | Average (52-58% TDN) | High quality (>58% TDN) |
|---|---|---|---|
| Dry pregnant cow | 1.8% BW | 2.0% BW | 2.2% BW |
| Lactating cow, early | 2.4% BW | 2.8% BW | 3.1% BW |
| Lactating cow, late | 2.1% BW | 2.4% BW | 2.7% BW |
| Growing heifer | 2.0% BW | 2.4% BW | 2.7% BW |
| Stocker/backgrounder | 2.1% BW | 2.5% BW | 2.9% BW |
| Finishing steer | 2.0% BW | 2.3% BW | 2.6% BW |
| Mature bull | 1.7% BW | 1.9% BW | 2.1% BW |
Calculators to run next
- Cattle Protein Supplement CalculatorUse when the hay tests short on protein and you need a feeding rate and a cost.
- Cost Per Pound of Gain CalculatorUse when deciding whether to feed cattle longer or sell them now.
- Feed Conversion Ratio CalculatorUse to judge how efficiently a pen is turning feed into pounds.
- Creep Feed CalculatorUse before rolling a creep feeder out to the calves this summer.
- Cattle Mineral Intake CalculatorUse when consumption is running over or under label target and mineral costs are drifting.
- Silage Tonnage CalculatorUse to inventory a bunker before winter or to size a pile at harvest.
Guides that use this calculator
- Body Condition Scoring Beef Cows and Why BCS 5 PaysWhat each score looks like by hand and eye, and why a cow calving at BCS 4 costs you a breeding season.
- Developing Replacement Heifers to a Target Breeding WeightTarget weight, required ADG, and the true carried cost of a home-raised heifer by the time she weans her first calf.
- Protein Supplement on Dormant Forage: When It Pays and When It Does NotDormant grass below 7 percent crude protein slows the rumen. Supplement fixes intake — if you price it per pound of protein.
Questions ranchers ask
How much dry matter will a cow eat per day?
A mature dry cow typically eats about 2.0-2.2% of her body weight in dry matter on average forage — around 24-26 lb DM/day for a 1,200 lb cow. Lactating cows on good forage can eat 2.6-3.0% of body weight, and calves and yearlings on high-quality feed can exceed 3%.
Why does forage quality change dry matter intake?
Low-quality, high-fiber forage sits in the rumen longer and digests more slowly, so it physically fills the animal before her energy needs are met — this is called gut fill limitation. Higher-TDN forage passes through faster, which lets cattle eat more pounds per day and actually get more energy overall.
What percent of body weight do lactating cows eat?
Early lactation cows with peak milk demand commonly consume 2.8-3.2% of body weight in dry matter, tapering to roughly 2.2-2.6% in late lactation as milk yield declines. Nursing a calf raises energy demand well above a dry cow, and intake capacity rises with it.
How do I convert dry matter intake to as-fed hay pounds?
Divide the DM figure by the forage's dry matter percentage. If a cow needs 26 lb DM/day and the hay tests 88% dry matter, she needs 29.5 lb of hay as fed. Wetter hay, silage or baleage requires proportionally more as-fed pounds to deliver the same dry matter.
Does cold weather increase how much cattle eat?
Yes. Below the animal's lower critical temperature, maintenance energy needs rise and cattle typically increase voluntary dry matter intake 5-25% to compensate, depending on wind, wet hide condition and how far below the threshold the temperature falls. Wet, windy cold drives intake up faster than dry cold.
How much hay do I need per cow for the winter?
Multiply daily as-fed pounds by the number of feeding days, then add 10-15% for storage and feeding waste with ring feeders, more for unrolled hay on the ground. A 1,200 lb dry cow eating roughly 27 lb of hay a day for 120 days needs about 1.8 tons before waste, closer to 2 tons after it.
Why is stocker cattle intake different from mature cows?
Growing cattle prioritize both maintenance and gain, and their rumen capacity relative to body weight is proportionally larger than a mature cow's. Stockers on a growing ration commonly eat 2.3-2.8% of body weight in dry matter, and the figure climbs further on high-concentrate finishing diets.
Can I use this calculator to size a bunk or feed wagon?
Use the herd total dry matter and as-fed figures as a starting daily budget, then check it against 30-45 days of actual feed disappearance once cattle settle in. Book values are a planning start point — bunk reading and body condition scoring are what confirm the ration is working on your operation.
Feed budgets and cattle purchases both start with real numbers
Underestimating intake is how hay runs short in February. The same discipline applies when buying — every Agrilot lot lists verified weights and seller history so you can budget feed against the actual pounds of cattle you are bringing home, not a guess off the trailer.