On a Friday in mid-July 2010 the area around west central Kansas was forecasted for high heat, high humidity and virtually no wind. Temperatures that afternoon were in the mid-90s, humidity was above 80%, and the air was still. Nels Lindberg, DVM, Production Animal Consultation, Great Bend, Kan., was at a yard in western Kansas, and cattle began to die that afternoon while he was there. “At this particular yard, heat deads would occur sporadically, but not in the number they were about to have,” he says.
Lindberg’s phone began ringing from managers from many other yards that afternoon, evening and the next day, with reports of hundreds of cattle dying in the heat in yards from capacities of 4,500–50,000 head. Death loss was 98% fat cattle, mostly blacks, but some other colored cattle also died. “We also had death loss in yards that processed newly received cattle too late in the morning, and the calves never got a chance to cool down,” Lindberg explains. “In most of these scenarios, the cattle were put into the yard Thursday night where the temperature never dropped below 80°F overnight. They came through heat getting there, never cooled down, were processed late, and had death loss on Friday.”
Death loss ranged from 0–10% of entire yards over those two to three days, and Lindberg’s individual yards had from zero to over 450 head lost per yard. Total losses in Lindberg’s\yards were over 2,500 head. Lindberg says the same weather patterns stretched into the rest of the weekend.
Immediate steps that were taken
Lindberg says the immediate actions taken were multiple and different depending on the feedyard, considering management, personnel numbers and abilities, geographical location, equipment available, and triage methods. “It was really too late to move any cattle to shaded or improved airflow pens, but extra water tanks in pens to increase water tank bunk space was recommended as well as bedding and physically walking or riding pens trying to break up the cattle,” he says. Adding some bedding to the pens acts as an insulator between the cattle and the hot ground.
Sprinkling was used as well in a few places, but was recommended to manage that use tightly to decrease the amount of water build-up. “In a couple of yards we also tried to make water tanks out of the actual bunk, by blocking off half the bunk and filling it with water,” he explains. “But, that only works in a level, flat, continuous poured bunk-line. It works okay, but my preference is still extra water tanks in the pens.” All of these management recommendations required a certain amount of labor, and Lindberg recommended to also keep the feedyard employees’ health in mind, as it was intensely hot and heat exhaustion or stroke could occur.
Current heat stress plans
Though you can’t change the weather, Lindberg says you can use some tools to predict when you might have problems. Coming into the summer of 2011, Lindberg has put into place some strategies to help his feedyards prepare for the worst.
“It is imperative to discuss the potential for heat events now with all employees of feedyards, from top to bottom,” Lindberg advises. “With managers and crew foreman, we need to be discussing action plans, standard operating procedures and what we need to do now to be prepared for heat events that will occur this summer. From there, we need to discuss with processing, hospital, cowboy and even maintenance crews, the finer details in order to put our SOPs and action plans into place to work and succeed.”
One thing Lindberg has implemented is having his feedyards use a heat stress forecast map such as the ones the USDA Agricultural Research Service provides (see Resources). “I have all mangers monitor this so we can more accurately predict these situations,” he says. The thermal-neutral zone for cattle is 59–76°F, so keeping an eye on those forecast maps can help feedyards keep an eye on the weather.
If a heat event is forecast, begin to look at upcoming processing schedules and adjust accordingly, Lindberg advises. “Look at shipping schedules and communicate to the packer if you need to.” If it is possible to move any predicted heat stress cattle to shaded pens, that can also help. Begin to put out extra water tanks in predicted heat stress pens, and potentially bedding as well. The bedding is used for similar reasons as is in the winter, to insulate the cattle from the hot soil or surface. Certain cattle will go to it, and others won’t. Also, make any ration changes necessary to try and make a lower heat-producing ration.
Lindberg has talked to some of his feedyards about the ability to put up short-term shades, such as something that can be hung up rapidly along a fenceline or bunkline (see Practice Tips). “We have looked into various types of materials such as the plastic snow fence, and trampoline-type materials,” he says. “This would be something more temporary, and much less cost-prohibitive than permanent shades. We know shades are one of, if not the best management option, it just can be very costly.”
Also, always keep employees in mind, Lindberg stresses. “Supply them with electrolyte powder packs or any sort of electrolyte drink to aid with their hydration and well-being.”
When you have time to plan
It may be too late to make major modifications or structural changes to a feedyard for this year’s heat stress potential, but it’s never too early to plan for heat stress events in the future. Water availability is the number one area that needs to be addressed for heat stress issues. “From a management standpoint, we need to start thinking about water tanks and having them available, as well as how to deliver the water to the tanks such as a water truck, high flow pumps, etc.,” Lindberg says. “We also need to prepare the permanent water tanks for the summer, and determine if any sort of tanks need their lids removed to increase space or have the balls taken out.” Lindberg notes that he had one yard where all of its deads occurred in pens with the frost-free tanks, but there were none in the pens with the open, cement tanks. “The frost-free tanks are not as open and fewer cattle can drink out of them or get to them at once.”
Lindberg says water tanks need to have the ability to refill at an adequate enough pace during high volume usage. “Keep in mind, water consumption will go down as temps go over 90°F, but will come back up as it cools down,” he says. Regular open-faced cement water tanks seem to be the best type water tank for these conditions. “I have concerns with water intakes during times of heat stress with any other style of tank,” he says. Also, “Sprinklers are used in central and western Kansas, but I would say on a limited basis. We have to be able to manage them so that we don’t create mudholes and more ground-level humidity. If we can’t manage them well, we can create a negative effect.”
If a yard has known water flow issues in times of heat stress, Lindberg recommends trying to address those so that increased output can occur at the peak needed times. This can be accomplished through larger water lines, larger holding tanks, towers, or pools, added wells or lowering wells. Also, ensure good, clean, well-groomed pens, eliminating manure or mud build-up, this again, reduces the ground level humidity. “If needed, you can communicate with the local fire department for their help in soaking down cattle and the ground in severe emergency situations,” Lindberg suggests. “From a marketing standpoint, you can also evaluate the need to market some predicted heat-stress cattle sooner than normal.”
If building, or upgrading facilities at a feedyard in heat-stress prone areas such as the central and eastern Plains and maybe even further west, think about shades. There are numerous types of and ways to design shades, but placement within a pen is extremely important so that the shaded area moves as the day goes on, Lindberg says. “If the shaded area stays the same, then that presents some challenges in regard to receiving any sort of precipitation and creation of mud that then is always shaded and dries more slowly,” he says. Certain angles of shades can also be used to help generate airflow within a pen.”
Lindberg says today there are many ways to make shades out of a wide assortment of materials. “Shades can be made portable or permanent, and can be made of different materials, but more commonly trampoline material or some sort of metal,” he says.
When advising clients about the potential for shade construction, it’s important to look past just the cost of the shades. “We have to begin to think about shades beyond decreasing losses in heat events,” Lindberg says. “We need to think about their return on investment in terms of feed intakes, conversions, average daily gain and the improvements we get in those numbers. Research has shown a good ROI in regard to performance and showing it in the closeouts. We just sold fats for $1.22 — that is $1,400–$1,600 per animal, with corn at $6–$7, and depending on a yard’s cost to put up or build shades, the economics we are working on now are very different than they were even two years ago. The equity we lost from last summer’s heat event cost us millions of dollars, and on top of that, what was lost in performance? But, due to short term memory, and only occasional events such as what we had, we tend to move on until it happens again.”
Think about what type of cattle are in which pens. “It’s important to think about the placement of cattle around lagoons,” Lindberg notes, “as well as airflow around a lagoon. Placement of fat cattle near lagoons and low airflow sections of a yard can be very detrimental to their health in heat events.”
What to do with the deads
Last year Lindberg’s feedyards not only had to try and limit losses during the heat stress event, but they also had to dispose of those losses. “The renderers were gathering more trucks and working as fast as they could, but they were limited in their ability to provide adequate services,” he says.
“We then relied on using emergency disposal sites, in which the yard has to get approval for first, from the appropriate regulatory agency. In any catastrophic event, we have to be able to address how we are going to dispose of high numbers of mortalities in a short amount of time, because as time goes on, decomposition continues to occur, and we can’t send trucks out with waste leaking out the back. For yards to dispose of hundreds of fat cattle in a short amount of time, takes time, people keeping track of animals, and a lot of logistics to get it done.”
Yards need to have an SOP for heat events, with details about actions to carry out when it occurs. “Put it on paper and review it with the entire feedyard, all crews, at the end of May,” Lindberg recommends. “This allows everyone to be involved, informed and a game plan intact and ready to be put into place when called upon. Hopefully these plans will help eliminate mistakes, make feedyards more efficient when going through the process, and save cattle.”
Sidebar: Heat stress risk analysis program
A heat stress risk analysis program developed by Meat and Livestock Australia helps veterinarians and produc-ers enter risk factors such as temperature, humidity and wind speed into a program that then helps define risk and offers management guidance to help mitigate heat stress. Tom Noffsinger, DVM, Benkelman, Neb., uses this system and says, “This tool allows producers to watch heat index risk changes in response to mitigation ef-forts.” The program also includes a “Heat Load Index (HLI) calculator” where the user can enter various meteo-rological parameters to determine an HLI value.
Australian veterinarian Kev Sullivan, from Bell, Queensland, offers two sites for accessing the information.
Sidebar: Watch for signs of heat stress
Heat stressed cattle will display different levels of clinical signs that feedyard personnel should watch for. The first says Lindberg, is that cattle begin to mill around and are restless with an increased respiratory rate. They may also standup more than laying down comfortably. Next, cattle will begin to salivate or drool, have an in-creasing respiratory rate, stand around and also begin to stand in the shade of fencelines.
As cattle get hotter, they excessively drool or foam at the mouth, open-mouth breathe occasionally, continue to stand in the shade of the fencelines or group together and gather around water tanks.
When cattle get critically heat-stressed they will stand grouped together, open-mouth breathe, have their ton-gues out, drool excessively and group around water tanks.
Heat stress resources
* See “The Heat Is On” Bovine Veterinarian July 2010
* Visit the Great Plains Veterinary Educational Center and search for “Heat Stress”
* USDA Agricultural Resources heat stress forecast map