Bioclimatic zoning for dairy cows in Brazil by statistical modeling

Area of Science:

• Animal Science
• Environmental Science
• Agricultural Science

Background:

• Climate conditions significantly influence animal welfare and dairy production.
• Brazil's Midwest is a major cattle-producing region, making it crucial to understand climate impacts.
• Bioclimatic zoning is essential for assessing and mitigating climate-related risks in dairy farming.

Purpose of the Study:

• To establish bioclimatic zoning for dairy cattle in Brazil's Midwest region.
• To assess the impact of climate conditions on milk production.
• To estimate potential milk production losses due to heat stress.

Main Methods:

• Utilized a 30-year historical dataset (1989-2019) of air temperature and relative humidity from NASA/POWER.
• Calculated the Temperature and Humidity Index (THI) for the hottest and coldest months.
• Estimated milk production decreases for two daily production levels (10 kg and 25 kg).

Main Results:

• The Midwest region experienced three THI classifications: 'normal', 'alert', and 'critical alert'.
• Autumn and winter showed no milk production loss for either production level (10 kg or 25 kg).
• Spring and summer saw a 1-2 kg milk reduction for 25 kg producers in the southern Midwest; 10 kg producers had no reduction.

Conclusions:

• Heat stress poses a risk to dairy cattle in Brazil's Midwest, particularly during spring and summer.
• High-producing cows (25 kg/day) are more susceptible to milk production losses.
• Only Sinop and Cuiabá avoided 'critical alert' THI classifications during the high-risk spring/summer period.