After a cold winter that seemed to go on forever, spring has lasted about two weeks and summer is now here. The USDA-NOAA heat stress forecast indicates that heat stress conditions will be elevated this weekend. Although conditions are not going to be severe, the entire state will be under a high heat warning on Saturday and Sunday. Temperatures this warm, early in the year before cattle have a chance to acclimate may cause some issues.
For feedlot cattle, do not expect an elevated risk for death loss but expect intakes to back off a little as cattle adjust. This would be a good time to make sure water flow is appropriate for increased summer intakes, shades are in place and sprinklers are in working order.
The biggest concern for this weekend is the cowherd. Many cows have not shed their winter coats and will not be able to regulate body temperatures well. Memorial Day weekend is also a common date for cow-calf producers to start artificially inseminating cows while some are turning bulls out. For those producers still not finished calving the heat can be hard on newborn calves. Dehydration will occur rapidly for calves with mild scours or that are separated from their dam.
Temperatures above thermoneutral (above 75-80 degrees Fahrenheit) have been shown to decrease conception rates. Once temperatures increase in the morning, heat detection will be harder this weekend as visible signs of estrus will be depressed. If you are planning on timed insemination protocol, set up your cows to breed first thing in the morning. Try to get cows bred as quickly as possible but do not bring too many at a time where they are standing in a holding pen getting hot without water. Avoid working cows in the heat of the day. Time removal of the CIDR to coincide with AI during the coolest time possible.
After insemination procedures are complete, keep the cows as cool as possible. A pasture with shade trees, plenty of water and good airflow would be ideal. If cows will remain in a lot for the weekend, provide plenty of water and shade if possible.
Source: iastate.edu