Ten multiparous lactating Holstein cows
were arranged in a replicated 5 × 5 Latin
Square design to evaluate the effect of soaking
frequency and volume of water per soaking on
lactating cows housed in a tunnel-ventilated
and evaporative-cooled freestall barn. Rectal
temperature, respiration rate, and body surface
temperatures were measured every 5 minutes.
Treatments were: control (C); soaking every 5
minutes with 0.26 gallons (5L); soaking every
5 minutes with 0.53 gallons (5H); soaking
every 10 minutes with 0.26 gallons (10L); or
soaking every 10 minutes with 0.53 gallons
(10H). Average ambient temperature and humidity
were 86.5ºF and 68% outside the barn,
and 80.4ºF at 86% inside the barn, respectively.
Water having a temperature of 80.6ºF
was applied manually from the shoulder to the
tail. Treatments were applied after three initial
measurements were assessed. Seventeen
measurements were made during treatment
application and five measurements after the
treatments were stopped. Air velocity over the
shoulder of the cows was 4 mph. Respiration
rate and body surface temperature for all
treatments were less than those of the control,
except for rear udder surface temperature in
the 10L treatment. Rectal temperature for 5L,
5H, and 10H were less than those of the control.
Respiration rate for 5L and 5H were less
than that of 10L. These data indicate that
soaking can be used in combination with tunnel
ventilation and evaporative pads to reduce
heat stress.
