Winter feeding & cold stress calculator
When it drops to -30 °C with a north wind, cows burn more energy just to stay warm. Enter the weather and your ration to see roughly how much more feed the herd needs.
What your cows feel
That is more than most cows can eat in extra hay. In this kind of cold, higher-energy feed (grain or pellets), shelter, bedding and a check of body condition usually matter more than more forage. Talk to your nutritionist or veterinarian.
- Per cow per day
- 6.2 lb
- Whole herd per day
- 618 lb
- Whole herd, all 7 days
- 4,323 lb = 1.96 t
- About this many extra bales
- 3.1
- Extra feed cost
- $294
- Grain or pellets per cow per day
- Not needed above -20 °C
- Whole herd per day
- -
Feed intake at this temperature: Below -15 °C: intake up about 8 to 25%.
Comfort limits by coat
| Coat | Comfortable down to (°C) | (°F) |
|---|---|---|
| Dry, heavy winter coat | -8 | 18 |
| Dry winter coat | 0 | 32 |
| Dry fall coat | 7 | 45 |
| Wet or matted coat | 15 | 59 |
| Summer coat | 15 | 59 |
Getting the herd through a cold snap
- Keep coats dry. A wet or muddy coat loses most of its insulation, so cows feel the cold at much warmer temperatures.
- Block the wind. Windbreaks work best at about 25 to 33% porosity and shelter an area 8 to 10 times their height.
- Bed them down. Straw between the cows and frozen ground or snow saves energy, and calving areas need it most.
- Don't count on snow for water. It isn't always there, clean or soft enough to eat. Check waterers twice a day.
- Watch thin cows. Cattle in poor body condition feel cold stress sooner and lose condition faster. Sort and feed them separately if you can.
Where these numbers come from
Comfort limits (lower critical temperatures), the rise of about 2% in energy needs for every degree below them, the feed-intake ranges, the extra-grain rule (1 lb or 0.45 kg of grain or pellets per cow per day for every full 5 °C the midday temperature is below -20 °C) and the tips above come from the Beef Cattle Research Council's Winter Management of Beef Cattle (reviewed December 2024; intake figures adapted from NRC 1981). Wind chill uses the Environment and Climate Change Canada wind chill formula, which was made for people; we use it only as a guide to the colder "effective temperature" cattle feel in the wind. Extra feed assumes the same ration gets fed in larger amounts; a cow can only eat so much, so very cold weather usually calls for richer feed rather than just more hay. This is a planning guide, not a ration: for your herd, talk to a beef nutritionist or veterinarian, or your provincial agriculture department. Nothing you type is stored or sent anywhere.
Short on hay this winter?
Find hay, feed and livestock on the REALM Marketplace, or plan the whole winter with the feed budget calculator.