Posted by Dr. Sara Barber on July 14 2009 09:51
Affects of Heat on Bulls
- Bull exposed to 95 degree temperature
- 70% increase in abnormal sperm
- 20% decrease in motility
- Sperm content did not return to normal for 40 days
When do cows become heat stressed?
- This is a combination of temperature and humidity
- Temperature-humidity index of 72
What are the symptoms of heat stress?
- Rectal temperature over 102.5 degrees
- Cows respiratory rate is over 80 breaths/minute
- Milk production drops more than 8-10%
- Dry Matter Intake drops more than 8-10%
How can you minimize the affects of heat stress?
- Water
- Water intake can increase by as much as 50%
- Cool, clean water needs to be available at all times
- Minimize competition to water
- Two waters per pen!
- Cooling systems
- Shade: Cover the feed and water areas
- Fans and sprinklers
- Start in the holding pen
- Start sprinklers when temperature exceed 78 degrees
- Sprinklers need to wet the skin not just the hair
How can you minimize the affects of heat stress?
- Supplement electrolytes (Bluelight in the water)
- Feed management
- Feed twice a day to reduce heat production and keep feed fresh - increase feed during cooler times of the day
Plan Ahead for Heat Stress
- Implement a program this spring
- Water
- Shade
- Reduce walking distance and holding pen time
- Holding pen ventilation
- Fans/Sprinklers