Dairy Cattle THI Analyzer
Assess heat stress levels with precision temperature-humidity index calculations
Heat Stress Reference
Mild heat stress begins, monitor cow behavior
Mild to moderate heat stress begins
Moderate to severe heat stress begins
Severe heat stress begins
Formula used: THI = (1.8 × T + 32) – [0.55 – (0.0055 × RH) × (1.8 × T – 26)]
Where T is temperature in °C and RH is relative humidity percentage (Kelly and Bond, 1971).
Wind Effect: Each 1 m/s increase in wind speed reduces the THI by approximately 2 units.
Mitigation: Fans providing ≥1 m/s air speed at cow resting height can help reduce heat stress effects.
Adjusted THI (THIadj) Calculator
Livestock Weather Safety Index accounting for solar radiation and air movement
THIadj Formula (Mader et al., 2006):
THIadj = 4.51 + THI – (1.922 × V) + (0.0068 × SR)
Where:
THI = Temperature-Humidity Index
V = air velocity (m/s)
SR = solar radiation intensity (W/m²)
Thresholds: <74 (No stress), 74-78 (Alert), 79-83 (Danger), ≥84 (Emergency)
Heat Abatement ROI Calculator
Calculate the financial benefits of cooling systems for your dairy herd
Economic Calculation:
Revenue Increase = Herd Size × Milk Gain × Heat Days × Milk Price
Example (100 cows, 3 kg gain, 100 days, $1.03/kg):
100 × 3 × 100 × 1.03 = $30,900
With full system (7.5 kg gain):
100 × 7.5 × 100 × 1.03 = $77,250