Accurate live weight estimation is essential in livestock management, influencing nutrition, veterinary care, trading, and productivity. Farmers and veterinarians depend on precise estimations for correct dosing, balanced feeding, fair pricing, and performance evaluation.
Estimated Live Weight Calculator — Heart‑Girth × Length
Quick, evidence-based liveweight estimates for cattle, sheep, goats, pigs and horses. Metric & Imperial supported.
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Core Formulas for Estimated Live Weight in Livestock
Several empirical equations are used worldwide to estimate live weight from body measurements. The most widely applied are Shaffer’s formula, Schaeffer’s girth–length method, and modified regression models. Below are key formulas, with detailed explanations of each variable.
1. Shaffer’s Formula (for cattle)
Where:
- LW= Live Weight (kg)
- HG = Heart Girth (cm), measured behind the forelegs
- BL = Body Length (cm), measured from the point of shoulder to pin bone
Typical Values:
- HG: 120–220 cm in adult cattle
- BL: 100–180 cm in cattle
2. Schaeffer’s Formula (for dairy cattle)
Where constants differ for dairy breeds, producing more accurate predictions.
3. Estimation Formula for Sheep and Goats
Where:
- HG= Heart Girth (cm)
Range:
- Typical HG in goats: 60–100 cm
- Typical HG in sheep: 65–110 cm
4. Pig Live Weight Estimation Formula
Where:
- HG = Heart Girth (cm)
- BL = Body Length (cm), from ear base to tail base
5. Poultry Estimation (Broilers)
For poultry, regression models are often applied:
Where:
- Coefficients a,b,c vary by strain and must be calibrated experimentally.
Summary of Common Variables
| Variable | Definition | Typical Range (by species) |
|---|---|---|
| Heart Girth (HG) | Circumference behind forelegs | Cattle: 120–220 cm; Goats: 60–100 cm; Sheep: 65–110 cm; Pigs: 80–150 cm |
| Body Length (BL) | Shoulder to pin bone (cattle/sheep/goats) or ear to tail base (swine) | Cattle: 100–180 cm; Sheep/Goats: 60–100 cm; Pigs: 70–120 cm |
| Height at Withers (HW) | Ground to highest point of shoulder | Cattle: 100–160 cm; Sheep/Goats: 55–95 cm |
| Live Weight (LW) | Estimated live body mass | Varies by species and breed |
Extensive Reference Tables for Estimated Live Weight
To enhance usability, here are ready-to-use lookup tables for estimating livestock live weight from heart girth and body length.
Table 1: Estimated Live Weight of Cattle (kg) Using Shaffer’s Formula
| Heart Girth (cm) | Body Length 120 cm | Body Length 140 cm | Body Length 160 cm | Body Length 180 cm |
|---|---|---|---|---|
| 120 | 57 | 67 | 77 | 86 |
| 140 | 78 | 91 | 104 | 117 |
| 160 | 102 | 119 | 136 | 153 |
| 180 | 130 | 151 | 172 | 194 |
| 200 | 160 | 186 | 213 | 240 |
| 220 | 194 | 225 | 257 | 289 |
Table 2: Estimated Live Weight of Sheep and Goats (kg) Using LW=0.08×HG2LW = 0.08 \times HG^2LW=0.08×HG2
| Heart Girth (cm) | Estimated Live Weight (kg) |
|---|---|
| 60 | 288 |
| 70 | 392 |
| 80 | 512 |
| 90 | 648 |
| 100 | 800 |
| 110 | 968 |
Note: Actual field weights are lower due to species-specific correction factors.
Table 3: Estimated Live Weight of Swine (kg) Using LW=0.08×HG2
| Heart Girth (cm) | Body Length 80 cm | Body Length 100 cm | Body Length 120 cm |
|---|---|---|---|
| 80 | 44 | 56 | 67 |
| 100 | 56 | 69 | 83 |
| 120 | 67 | 83 | 100 |
| 140 | 78 | 97 | 117 |
| 160 | 89 | 111 | 133 |
Table 4: Approximate Live Weight Ranges by Species and Class
| Species | Class | Typical Range (kg) | Notes |
|---|---|---|---|
| Beef Cattle | Mature cow | 400–700 | Heavier in continental breeds |
| Dairy Cattle | Lactating cow | 450–650 | Holstein up to 700 kg |
| Sheep | Adult ewe | 50–90 | Breed-dependent |
| Goats | Adult doe | 35–70 | Dairy goats heavier |
| Swine | Market hog | 100–140 | At 5–6 months |
| Broiler Chickens | Market ready | 1.5–3.5 | Strain-dependent |
