MU

Animal Sciences

CAFNR

Thermal Aid

Recognizing Heat Stress • Normal Animal Values and Indexes • Heat Exchange in Livestock

Cattle
Body Temperature
  • • Normal = 100.4 – 103.1°F (38 – 39.5°C)
  • • Mild fever = 103.1 – 104.6°F (39.5 – 40.3°C
  • • Moderate fever = 104.6 – 105.8°F (40.3 – 41°C)
  • • High fever = 105.8 – 107.0°F (41 – 41.7°C)
  • • Very high fever = 107.0 – 110.0°F (41.7 – 43.3°C)
Respiration Rate
  • • Adult = 10 – 30 breaths/minute
  • • Young = 30 – 50 breaths/minute
Heart Rate
  • • Adult = 60 – 80 beats/minute
  • • 2 months – 1 year = 80 – 110 beats/minute
  • • 2 days – 2 months = 100 – 130 beats/minute
Estrus Cycle - 21 days
Gestation - 285 days

Body Temperature

Swine
Body Temperature
  • • Normal = 101.6 – 103.6° F (38.7 – 39.8°C)
Respiration
  • • Adult = 8-20 breaths/minute
Heart Rate
  • • Adult = 60-80 beats/minute
Estrus Cycle - 21 days
Gestation - 115 days

Body Temperature

Current Heat Indexes

Temperature, humidity and the amount of direct sunlight are the primary factors that determine an animal’s body temperature. However, other factors — such as precipitation, wind, amount of night cooling and exposure to fescue endophyte— are important. Cattle that are not acclimated to hot weather are also at greater risk if weather changes rapidly or if the cattle are moved to an environment with greater heat stress. Cattle that have eaten endophyte-infected fescue may have increased body temperatures and may be predisposed to heat stress.

• Swine (0.65 × Tdb) + (0.35 × Twb) Ingram (1965)
• Swine (0.75 × Tdb) + (0.25 × Twb) Roller and Goldman (1969)
• Laying hens ( Tdb × 0.60) + ( Twb × 0.40) Zulovich and DeShazer (1990)
• Turkeys ( Tdb × 0.74) + ( Twb × 0.26) Xin et al. (1992)
• Dairy cows Tdb + (0.36 × Tdp) + 41.2 Johnson and Vanjonack (1976)
• Beef cattle (0.8 × Tdb) + [rh × ( Tdb – 14.3)] + 46.3 NOAA (1976)
• Tdb in ◦C, Twb in ◦C, rh in decimal form, Tdp in ◦C