How much hay does a cow eat a day?

A cow eats about 2 to 2.5% of her body weight in dry matter a day, so a 1,200 lb cow needs roughly 30 lb of dry matter — about 34 lb of hay as it comes off the bale, before any waste.

How many round bales does a cow need for winter?

At 1,200 lb bales and 120 days on hay, a 1,200 lb cow fed from a ring feeder needs about 4 bales. Enter your own herd, days and bale weight for your figure.

How much hay is wasted feeding round bales?

Feeding trials put it around 5 to 15% with a good ring or cone feeder, about 20% unrolled on the ground, and 30 to 45% for a bale set out with no feeder at all.

How much hay does a goat or sheep eat a day?

Sheep eat about 3% and goats about 3.5% of body weight in dry matter a day. A 160 lb ewe needs about 5 lb of dry matter, or 5.5 lb of hay before waste.

How much hay do I need?

Head, weight and days on hay, to how many bales and tons to buy or put up — with what gets trampled allowed for, and what it costs.

Works for cattle, sheep & goats and horses. Free, no account, and nothing you type leaves your phone.

Head

Average weight

lb

Days of feeding

days

Bale weight

lb

Weigh a few if you can — they're rarely what the baler says.

Price per bale

$

Leave blank to skip the cost.

How it's fed

Daily intake

% of body wt

Dry matter. Raise it for nursing or late-gestation females.

Hay dry matter

%

88% is hay at about 12% moisture.

You'll need

194

bales · 116.2 tons

Put out a day: 1.61 bales
Per head a day: 38.7 lbwith waste
Total hay: 232,438 lb
Cost: $11,640
Cost per head a day: $1.94

Your numbers, step by step

Each animal eats 2.5% of 1,200 lb = 30 lb of dry matter a day.
Hay is only 88% dry matter, so that takes 30 ÷ 0.88 = 34.1 lb of hay as it comes off the bale.
With 12% wasted, you put out 34.1 ÷ 0.88 = 38.7 lb a head a day.
38.7 lb × 50 head × 120 days ≈ 232,438 lb, or 116.2 tons. (The total is worked from the unrounded daily figure, so it can differ by a few pounds from the rounded one shown.)
232,438 lb ÷ 1,200 lb bales = 193.7, rounded up to 194 bales, at $60.00 a bale = $11,640.

See a mistake, or a number that doesn't look right?

How this is calculated

The formulas

Dry matter a day: body weight × intake %
What the animal actually needs. Water in the hay feeds nothing.
Hay as fed: dry matter ÷ hay dry-matter %
Hay put out: hay as fed ÷ (1 − waste %)
Divided, not multiplied: waste is a share of what is put out, so the share that is eaten has to cover the need. Adding the percentage on top runs short.
Total, bales and cost: hay put out × head × days ÷ bale weight, rounded up; × price per bale

Where the defaults come from, and the limits

Intake. Cattle 2.5%, sheep 3%, goats 3.5%, horses 2% of body weight in dry matter a day — the middle of the ranges in extension feeding guides. Lactating and late-gestation females eat toward the top; change the figure if yours are.
Dry matter. 88% is hay baled at about 12% moisture. Haylage and baleage are far wetter — use the dry matter on its test.
Waste. round bale in a ring feeder 12%; cone or basket feeder 6%; unrolled on the ground 20%; round bale, no feeder 40%; ground hay in a bunk 5%. The middle of measured ranges from feeding trials.
Limits. Hay only. Grazing, cubes or grain fed alongside cut what is needed; take those days out, or lower the intake. Quality isn't considered: poor hay may be eaten in quantity and still leave them short of protein.

Questions people ask

How much hay does a cow eat a day?: A cow eats about 2 to 2.5% of her body weight in dry matter a day, so a 1,200 lb cow needs roughly 30 lb of dry matter — about 34 lb of hay as it comes off the bale, before any waste.
How many round bales does a cow need for winter?: At 1,200 lb bales and 120 days on hay, a 1,200 lb cow fed from a ring feeder needs about 4 bales. Enter your own herd, days and bale weight for your figure.
How much hay is wasted feeding round bales?: Feeding trials put it around 5 to 15% with a good ring or cone feeder, about 20% unrolled on the ground, and 30 to 45% for a bale set out with no feeder at all.
How much hay does a goat or sheep eat a day?: Sheep eat about 3% and goats about 3.5% of body weight in dry matter a day. A 160 lb ewe needs about 5 lb of dry matter, or 5.5 lb of hay before waste.

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