Animals that have spent months in a feedlot can be overcome by fatigue when it comes time to ship them to slaughter
Picture this: you’ve spent six months at a resort, lounging around and eating at least three times a day at the buffet. Drink is plentiful. You are fat and happy. Then you are asked to run a six-minute mile in 32 C heat.
Stressful? Possibly life-threatening?
It can be. And that is what heavy cattle in feedlots can face on shipping day, depending on the conditions.
Finished, heavy animals can suffer fatigued cattle syndrome, a condition brought on by rapid or aggressive movement over longer distances, combined with hot weather. Once moved, usually into a truck for transport to the processor, the cattle become stiff and sore, move slowly and in the worst cases, go down and cannot rise.
That combination of stress factors doesn’t often occur in western Canadian feedlots but they do in the big cattle-feeding regions of Nebraska and Kansas.
Dr. Dan Thomson, a veterinarian and researcher at Iowa State University, has studied fatigued cattle syndrome and he is worried about this summer.
“With this decrease in packer capacity today and more cattle being held and cattle that are going to be bigger in the summer, I have a lot of worry about things that we’re going to see, such as atypical interstitial pneumonia and fatigued cattle syndrome as we come into the summer,” he said during a recent webinar.
Thomson and his colleagues studied the condition by taking four groups of cattle, some lighter and some with more backfat. They moved some at a rapid rate and some at a walk, over distances of 800 and 1,600 metres, and then tested their lactate levels via blood tests. Lactate tends to build in muscles when exercised and is a factor in stiff and sore muscles.
Thomson found that cattle that were aggressively moved at a trot had higher lactate levels and higher cortisol levels, the latter being a sign of stress. Those moved at a walk had no increase in blood lactate. The heavier cattle also had higher levels than the lighter ones after being rapidly moved.
The message is clear, he said. Finished cattle must be moved slowly to load out, preferably over only a short distance, and in cooler conditions if possible. A rider, quad or person in front of the cattle herd can prevent the animals from running and set a sedate pace.
It takes patience to walk cattle slowly, he said, “but if you remember, on the Chisholm Trail, they didn’t run them north.”
The legendary Chisholm Trail, used to drive cattle overland from Texas to Kansas railheads, was used in the 1860s to 1880s, a process that took about three months.
“One of our big things that we have to address as we move forward is that we have to decrease the amount of time that the cattle wait on the truck at the packing plant, especially this summer and especially as big as these cattle are,” said Thomson.
Holding cattle longer in feedlots, likely through summer, is also a factor in western Canadian feedlots due to slowed packer operations as a result of plant worker and safety measure changes.
Fortunately, fatigued cattle syndrome is rare in this climate.
“It’s not too common in this part of the world, probably for a couple of reasons,” said Dr. Calvin Booker, a veterinarian and managing partner at Feedlot Health Management Services.
“You could create it here. In the summertime, on the hottest days, in black cattle, if you had to move them very rapidly over a long distance in the feedlot, you could create it.”
That combination is unlikely, however.
“A lot of our feedlots are not as big as some of the feedlots in the (United States), or they’re not as spread out as some of the feedlots in the U.S. so sometimes those distances that they need to move to the loading facility are not as far,” said Booker.
“We don’t often have all of those factors here, or when we do have that heat, it is actually really dry as well. We don’t have the humidity index to go with it, so our risk of it is lower. So that’s why we don’t really see very much of it.”
The other saving grace is that temperatures usually cool off at night in Western Canada, giving cattle a chance to dissipate heat built up during the day.
But keeping heavy cattle waiting on trucks for extended periods is a risk factor in Canada just as it is in the U.S., Booker added.
On hot days, cattle are fine when the trucks are moving but when they have to wait at the plant for any reason, heat quickly builds up on the truck. For that reason, careful co-ordination of shipping times and arrivals is the ideal scenario.
In the U.S., Thomson said fatigued cattle syndrome can be avoided through good stockmanship.
“It is a feedlot by feedlot phenomenon, not a weather or cattle-type phenomenon. The packers know which feedyards have consistently had fatigued cattle syndrome and it goes back to how you move those cattle out of the home pen and how you get them to the load out.”