Feeding Bison with Grass Hay
This page analyzes the use of grass hay as a feed source for bison. At 8% crude protein and 52% TDN, grass hay is fully suitable as a sole feed for bison at maintenance level (requires 7% CP and 52% TDN). Below you will find daily feeding rates, costs across herd sizes, and a life-stage breakdown showing how requirements change through the production cycle.
Grass Hay for Bison by Life Stage
Feed requirements change significantly across life stages. The table below shows the daily as-fed quantity of grass hay needed for each bison life stage, along with whether the feed meets the adjusted protein and TDN requirements for that stage. Life stages with higher demands (lactation, growth) may require supplementation even if grass hay is adequate at maintenance.
| Life Stage | Daily DMI | As-Fed/Day | Protein Need | Protein OK? | Monthly Cost |
|---|---|---|---|---|---|
| Cow | 36.0 lbs | 40.9 lbs | 7% | Yes | $92.05 |
| Lactating Cow | 43.2 lbs | 49.1 lbs | 9.8% | No | $110.45 |
| Growing Calf | 46.8 lbs | 53.2 lbs | 11.2% | No | $119.66 |
| Bull | 39.6 lbs | 45.0 lbs | 7.7% | Yes | $101.25 |
Herd Feed Budget: Bison on Grass Hay
For operations feeding grass hay to multiple bison animals, the table below projects total feed requirements and costs. These estimates use the maintenance-level feeding rate of 40.9 lbs as-fed per head per day at $150/ton.
| Head Count | Daily As-Fed Total | Monthly Tons | Annual Tons | Monthly Cost | Annual Cost |
|---|---|---|---|---|---|
| 1 | 40.9 lbs | 0.54 tons | 6.57 tons | $92.05 | $1,119.89 |
| 5 | 204.5 lbs | 2.70 tons | 32.85 tons | $460.23 | $5,599.43 |
| 10 | 409.1 lbs | 5.40 tons | 65.70 tons | $920.45 | $11,198.86 |
| 25 | 1,022.7 lbs | 13.50 tons | 164.25 tons | $2,301.14 | $27,997.16 |
| 50 | 2,045.5 lbs | 27.00 tons | 328.50 tons | $4,602.27 | $55,994.32 |
| 100 | 4,091.0 lbs | 54.00 tons | 657.00 tons | $9,204.55 | $111,988.64 |
Feeding Rates by Body Weight
The daily amount of grass hay varies with the individual animal's body weight. The table below shows as-fed feeding rates and monthly costs across a range of weights for bison.
| Body Weight | Daily DMI | As-Fed/Day | Monthly Feed | Monthly Cost |
|---|---|---|---|---|
| 1,260 lbs | 25.2 lbs | 28.6 lbs | 756 lbs | $64.43 |
| 1,530 lbs | 30.6 lbs | 34.8 lbs | 918 lbs | $78.24 |
| 1,800 lbs | 36.0 lbs | 40.9 lbs | 1,080 lbs | $92.05 |
| 2,070 lbs | 41.4 lbs | 47.0 lbs | 1,242 lbs | $105.85 |
| 2,340 lbs | 46.8 lbs | 53.2 lbs | 1,404 lbs | $119.66 |
Nutritional Analysis: Grass Hay for Bison
Grass Hay provides 8% crude protein on a dry matter basis, while bison at maintenance require a minimum of 7% crude protein. This means grass hay provides 1 percentage points of protein above the minimum requirement, giving adequate margin for variation in feed quality and individual animal needs.
For energy, grass hay provides 52% TDN compared to the bison requirement of 52% TDN. The energy content is adequate for maintenance and provides 0 percentage points of margin. Higher-demand life stages such as lactation or rapid growth may require energy supplementation with grain or fat even though the maintenance requirement is met.
The dry matter content of grass hay is 88%, meaning that for every 100 lbs of as-fed feed, the animal receives 88 lbs of actual dry matter nutrition and 12 lbs of water. At $150 per ton as-fed, the effective cost per ton of dry matter is $170. When comparing feeds, always use the dry matter cost rather than the as-fed cost to make fair comparisons between feeds with different moisture levels.
For a comprehensive feeding program, consider combining grass hay with complementary feeds that address any nutritional gaps. Browse the complete feed comparison to identify the most cost-effective supplements, or use the calculator to model different feed combinations. Always provide free-choice mineral supplementation and clean water regardless of the forage and grain program.
More Feeding Combinations
Explore other feed options for bison or see how grass hay works for other species.
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