Heat stress can be a significant cause of economic loss on the farm during the warmer months of the year. Excessive heat, humidity, drought, and over grazing can take a toll on your farm at many levels. Heat equates to stress on your animals, your crops, and your labor force (you). To successfully manage the heat of summer it’s important to understand the basics of what heat does to you, your livestock and your forages.
Heat stress on cool season grasses
Heat stress, particularly in climates suited for cool season grasses can have significant negative impacts on forage production. As the name suggests, they are well suited to these cooler parts of the growing season. Cool, season grasses grow best between 60-75°F while warm season grasses prefer temperatures in the 80-95°F range. During the hottest parts of the summer cool season grasses become much less effective forage producers. As the weather gets warmer, the soil temperature increases. As the night temperatures grow higher this problem expands. As the intensity of the summer heat grows rates of root maturation and root death increases, new growth of roots slows then stops. Under heat stress, fewer new leafs are produced on cool season grasses and the ones that do form are shorter and narrower. As soil temperatures exceed 104°F for extended periods, many cool season grasses simply begin to die.
There is not much we can do to change the temperature. However there are several things we can do to protect our cool season grasses. The lessons from the turf grass industry tell us that a simple elevation in the cutting height can greatly reduce the heat stress on cool season turf grass. While we may not be playing golf on our hay and pasture ground, we can look at the height we mow, when we mow and how short we graze. By preserving additional vegetation as we move into summer we encourage regrowth and shading of the soil. Over grazing or closely mowed hay ground can leave a tremendous amounts of soil surface exposed to direct sunlight and cool season grasses find this ill-suited for their regrowth.
The take home message about managing heat stress in cool season grasses is simple. To conserve your cool season grasses, leave more vegetation in the field, rotate off a little sooner, and mow a little higher or earlier. Look at alternatives such as warm season annuals as a mid-summer alternative to overgrazing stressed cool season grasses. Avoiding the freshly mowed look at the onset of summer can save pasture and hay meadows and allow them to thrive throughout the remaining seasons.
Heat stress on livestock
In ruminant livestock the process of the rumen converting forages into microbes and the microbes into livestock is a heat generating process. During the summer months this heat generation becomes a hindrance on production agriculture. Hot weather causes reduced dry matter intake, decreased average daily gain, decreased milk yield, decreased fertility and economic loss for the farmer. Managing the effect of heat stress requires your commitment to several small changes to keep your livestock as healthy and productive as possible.
A few simple changes in management can reduce the economic impact of heat stress in livestock. The first thing you to do is providing abundant water, and shade for your livestock. Do not work your livestock during extreme heat as this can make them hotter. Don’t crowd you livestock, and allow them access to shaded ground. Keep livestock where they can find a breeze or a fan and avoid radiant heat (direct sunlight). You may consider supplementing a little grain to offset the loss in production from decreases forage intake.
Heat stress on farmers and farm workers
Just like your livestock, you and your farm workers have limited abilities to cope with excessive heat. Our first line of defense is sweating. However when the human body fails to keep its core temperature in a safe range by sweating, several heat-induced illnesses and even death can occur. To work safely you should know the causes of heat induced illnesses, the symptoms of heat induced illnesses, and how to respond to heat induced illnesses.
The biggest factors in causing heat induced illnesses are temperature and humidity. Avoid exposure to direct sunlight or some persistent heat source. High humidity complicates temperature by lessening the effectiveness of sweating. The harder you work the more at risk you will be. Physical excursion generates heat. Any adverse health conditions or being in a poor physical condition can compound these and other factors. Each of these factors could lead to heat exhaustion, heat stroke, and even death.
When exposed to these conditions, watch for symptoms of heat induced illnesses. If you develop a headache, feel dizzy, light headed, experience weakness or start cramping you could be experiencing heat exhaustion. If you feel very hot but have stopped sweating, seem or feel confused, and lose consciousness you could be experiencing a heat stroke. While heat exhaustion is bad, heat stroke is worse. The inability to sweat and the depressed mental acuity are signs of the brain failing to control the overheating and your core body temperature reaching dangerous levels.
When working in the heat, pay attention to each other and watch for symptoms of heat related illness. When an emergency issue happens, don’t hesitate. In heat related emergencies simply call your local emergency medical services (EMS) at once. While waiting for the arrival of EMS personnel, find shade, get out of the sun, or move away from the source of heat. Loosen or remove heavy clothing exposing skin to air to improve the effectiveness of sweating. Provide cool drinking water to stressed individuals. Wet or moisten the skin of the individual and fan them. As the moisture evaporates from the skin it pulls heat from the body.
A better approach to managing heat stress is to avoid heat stress. Try to avoid extremely taxing and physical labor in the hottest part of the day. Drink a little cool water every 15 minutes or so to prevent overheating, even if you’re not thirsty. Periodically rest in the shade to cool down. Wear proper clothing such as a hat and light-colored clothing. Take action to reduce the effect of high temperatures and save yourself and your employees from life threating heat related illnesses. While working in the heat is often a requirement in agriculture, work smarter and don’t fall victim to a heat related illness.
