Dairy

Three Steps to Reduce Heat Stress Effects on Reproduction in Dairy Cattle

Management : Milk Production

Management : Transition & Lactating Care

Kevin Dill, Ph.D.

Senior Nutritionist – Dairy Technical Solutions

When warm weather sets in, both milk production and reproduction rates drop. 

Consider these three steps to identify signs of heat stress in cattle and help maintain reproduction through high temperatures and humidity.

Step 1: Measure dairy cow heat stress

When the summer heat spikes, it’s important to measure air temperature and humidity in your facilities to know when heat stress may be occurring. Early intervention can help keep reproduction levels and milk production from dropping.

Measuring the Temperature-Humidity Index (THI):
  • Calculates heat stress in dairy cattle by measuring air temperature and relative humidity.
  • Allows you to estimate your herd’s cooling requirements.
 
How: Work with your Purina® expert and use thermometer and hygrometer to measure the THI in your barn to know when your cows may be experiencing heat stress.  

Step 2: Understand the effects of heat stress on dairy cattlemonitor temperature humidity index for dairy cattle

Understanding how heat stress can affect your herd is the first step in stopping the summer slump.

Previously, researchers believed heat stress began at a THI of 72. Now we know from recent studies that: How: Review reproduction and milk production records with your local Purina expert to identify and focus on areas of opportunity during hot and humid weather.

Step 3: Monitor THI

To help maintain reproduction rates and milk production, consider implementing these steps to reduce heat stress in dairy cattle:

1 Purwanto, B.P., Y. Ab, R. Sakamoto, R. Furumoto, and S. Yamamoto. 1990. Diurnalpatterns of heat production and heart rate under thermoneutral conditions in Holstein Friesian cows differing in milk production. J. Agric. Sci. 114:139-142. 
2 Purwanto, B.P., Y. Ab, R. Sakamoto, R. Furumoto, and S. Yamamoto. 1990. Diurnalpatterns of heat production and heart rate under thermoneutral conditions in Holstein Friesian cows differing in milk production. J. Agric. Sci. 114:139-142. 
Garcia-Ispierto et al., 2006
4 do Amaral, B.C., E. E. Connor, S. Tao, J. Hayen, J. Bubolz, and G. E. Dahl. 2009. Heatstress abatement during the dry period: Does cooling improve transition into lactation? J. Dairy Sci. 92:5988-5999.