When livestock reach the highs in the heat zone it can be detrimental to their health
I spent much of the spring wondering if summer would ever arrive, and she definitely chose to bare her teeth last week. Weather-wise, conditions have completely flipped from a month earlier.
Many of you were struggling to get crops in the ground from the wet field conditions. Now, I think many of you are begging for a good rain. I know they have always joked, “If you don’t like the Ohio weather, wait until tomorrow,” but this is a little crazy. I guess nothing is normal anymore.
While many of us may love the warmer weather, although not 90 degrees, it doesn’t take much to create heat stress issues for our livestock. We will often hear the weathermen report the actual temperature and the “feels like” temperature, which can often be drastically different. In the livestock world, we go by a different measure to determine when animals may begin experiencing heat related stress.
The thermal heat index (THI) is a chart that was created to factor in the temperature and humidity to create thresholds for when animals could begin to experience heat stress. I am not sure of the math behind the THI, but you can readily find a chart on the internet.
More: The ins and outs of gathering and preserving your forage
In the heat zone: Recognize signs of heat stress on livestock
When we consider that our ruminant livestock (cattle, sheep, goats, etc.) have a heat generating fermentation vat in their bellies, the threshold where livestock experience heat issues can be surprisingly low. In fact, at a temperature of 76 degrees and humidity at or above 85%, we are entering the “alert” zone of 75 on the THI chart. A thermal heat index of 84 is the “emergency” zone where extreme caution needs to be taken for our livestock. The emergency level can be reached at a temperature of 86 degrees with a relative humidity of 85% or greater. It was easily reached last week with an air temperature of 94 degrees and a relative humidity of 50%.
It is important to be able to recognize the signs of heat stress. Stressed livestock will group up when on pasture, they will breathe with their mouths open and have a depressed disposition with their ears and head down. Stressed livestock produce higher levels of the hormone cortisol.
These elevated levels will interfere with many of the normal biological processes and can lead to digestive complications, infertility or early embryonic death, and the failure of vaccines and antibiotics. There is only so much you can do when livestock are housed outside.
The key is to provide ample access to cool, clean water and shade. You also should limit livestock handling activities. If you must work your livestock, try and coordinate the activities to happen early in the morning or late in the evening when temperatures are cooler. Work animals in small groups to limit their time standing in the handling facility to 30 minutes or less.
Avoid working or transporting animals that are sick, lame or of low body condition. For animals housed in barns, maximize air flow through the facility. If you have a sprinkler system, periodically wet the animals, and give the water time to evaporate off before water is applied again. This will maximize cooling and also limit water usage.
Summer programs: Grazing school, Manure Field Day
There are several summer programs I would like to make you aware of. First, the Richland County Soil and Water office will hold a grazing school July 23 and 25. If you would like to find more information or register for any of their programs, you can reach them at 419-747-8684.
The Tri-State Manure Field Day will be held July 11 at Green Top Acres in Payne. The day starts at 8:30 a.m. Lunch will be provided. The topics include demonstrations of the 360 Rain manure applicator, emergency spill response and a rainfall simulator. There will be educational presentations on manure safety and regulations for Ohio and Indiana. The program will conclude with an optional tour of the Green Top Acres facility. For more information, or to register, contact Paulding County Soil and Water at 419-523-5159.
The Wayne-Ashland Dairy Service Unit has set the date and location for this year’s dairy producers’ summit and Twilight Tour. The event will be held July 16 at the Wayne County Fairgrounds. The dairy producer summit will be held 3-5 p.m. The Twilight Tour will run 6-9 p.m. and feature a farm to table program. Attendees will get to experience how food is grown. Several local food vendors will be on hand to provide meals. One change for this year is there will be $10 per person charge for dinner. Attendees will get a voucher for free ice cream.
The 2024 OSU Manure Science Review will be held at the Molly Caren Agricultural Center in London, Ohio, on Aug. 6. The program will feature presentations and demonstrations on manure placement and subsurface drainage, 360 RAIN liquid manure application, best manure applications practices, H2Ohio updates, manure spill mitigation, spreader calibration and autonomous tractor demos. You can find the event flyer and registration materials at https://ocamm.osu.edu.
As always, if you have any livestock or forage management questions, please feel free to contact me at the OSU Extension office – Wayne County at 330-264-8722 or email me at yost.77@osu.edu.
John Yost is an Extension Educator IV, Agriculture and Natural Resources, at OSU Extension-Wayne County.
This article originally appeared on The Daily Record: Farmers urged to keep an eye out for heat stress on livestock
