牧草地収容頭数計算機
牧草地が何頭の家畜を支えられるかを計算。収容能力、放牧期間、輪番放牧計画を取得。
| 家畜の種類 | 平均体重 | AU換算値 | 月間飼料量 |
|---|---|---|---|
| 牛（繁殖牛） | 1,000 lbs | 1 | 780 lbs |
| 牛（育成牛） | 600 lbs | 0.7 | 546 lbs |
| 羊 | 150 lbs | 0.2 | 156 lbs |
| ヤギ | 120 lbs | 0.17 | 133 lbs |
| 馬 | 1,100 lbs | 1.25 | 975 lbs |
| 豚（放牧） | 250 lbs | 0.4 | 312 lbs |
家畜単位（AU）換算値は、標準的な1,000lbの牛を1.0 AUとして算出しています。
| 飼料生産地域 | 年間収量 | 1エーカーあたりのAU |
|---|---|---|
| 米国南東部（多湿） | 5,000 | 0.27 |
| 米国中西部（丈の高い草原） | 4,000 | 0.21 |
| グレートプレーンズ（混合草原） | 2,500 | 0.13 |
| 乾燥西部（放牧地） | 1,200 | 0.06 |
| 太平洋岸北西部 | 4,500 | 0.24 |
| 米国北東部 | 3,500 | 0.19 |
飼料収量は地域平均です。実際の生産量は土壌、降雨量、管理方法によって異なります。
Understanding Stocking Rate
Stocking rate is the number of animals grazing a given area for a specific time. It's the most important management decision a livestock producer makes — overstock and you degrade pasture, understock and you leave money on the table.
The standard unit is the Animal Unit (AU): one 1,000-lb cow with calf consuming about 780 lbs of dry forage per month. Other livestock are expressed as fractions: sheep ≈ 0.2 AU, goats ≈ 0.17 AU, horses ≈ 1.25 AU.
Carrying Capacity by Region
| Region | Forage (lbs/acre) | ~Acres per Cow |
|---|---|---|
| Southeast US | 5,000 | 2–3 |
| Midwest (tall-grass) | 4,000 | 2–4 |
| Great Plains (mixed) | 2,500 | 4–8 |
| Arid West | 1,200 | 8–15 |
| Pacific NW | 4,500 | 2–4 |
Rotational Grazing Basics
Dividing pasture into paddocks and rotating livestock through them allows each paddock rest time for regrowth. The “take half, leave half” rule (50% utilization) is the gold standard. With 8 paddocks grazed 3–4 days each, rest periods reach 21–28 days — enough for full recovery in most climates.
Frequently Asked Questions
How many cows can I run per acre?
It varies by region. In productive Southeast pasture (5,000 lbs forage/acre), about 1 cow per 2 acres. In the arid West (1,200 lbs/acre), you may need 8–10 acres per cow.
What is an Animal Unit Month (AUM)?
An AUM is the forage needed for one 1,000-lb cow with calf for one month — about 780 lbs of dry matter. Sheep are ~0.2 AU, horses ~1.25 AU.
What utilization rate should I use?
50% is the standard (“take half, leave half”). This maintains pasture health and root reserves. Going above 65% risks overgrazing.
How does rotational grazing improve capacity?
Rotational grazing can increase carrying capacity 25–50% vs. continuous grazing by allowing paddocks adequate rest for regrowth.
How many paddocks do I need?
Minimum 4, ideally 8–12. More paddocks = longer rest periods. With 8 paddocks grazed 3–4 days each, rest periods reach 21–28 days.
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