Calves often arrive at the feedlot unvaccinated, with horns and unaccustomed to using a feed bunk or water tank
Every fall, millions of calves end up in sale barns where they can be exposed to diseases, transportation stresses and other injuries.
Feedlots commonly buy calves that have not been vaccinated, dehorned and are not accustomed to eating from a feed bunk or drinking from a water tank, said Dan Thomson, a veterinarian at Kansas State University.
“It is a good thing we have a short memory in this industry because we are going to line up and buy these high-risk calves again,” he said.
Those calves are vulnerable to bovine respiratory disease and some may die.
“Sick cattle don’t eat and cattle that don’t eat get sick,” he said at the June University of Calgary veterinary summit .
Calves should be eating 1.5 percent of their body weight by 10 to 14 days on feed. There is a decrease in illness among those weighing about 600 pounds or more.
“Ten percent of cattle that are truly sick with BRD will die regardless of how you treat them,” he said.
Huge numbers of calves may arrive at a feedlot at once and it can overwhelm the staff trying to get them processed and settled.
“The more new high-risk cattle you have at a facility, the higher risk your low-risk cattle become because you are spending more time (with the sick ones),” he said.
The cattle may have travelled great distances and when they arrive they need to rest with water and feed and go into dry pens. For every hour a calf is on the truck, it should get an hour of rest before processing.
When these calves arrive in hot or muddy conditions, it increases their vulnerability.
Large facilities tend to manage incoming cattle quite well. Thomson’s greater concern is farmer feeders who buy a few at a time and keep adding them to the same pen.
Research shows if it takes more than five to seven days to fill a pen, more respiratory illness emerges.
Many of these animals have not been vaccinated for many common diseases. Thomson favours treating them all with antibiotics upon arrival. About 77 percent of feed-yard consulting veterinarians provide feed grade antibiotics for high-risk calves. This practice needs more research.
“The number one control of morbidity and mortality for bovine respiratory disease in high-risk calves is metaphylaxis, mass treatment with antibiotics at the time of arrival,” he said.
Calves can also get sick because of labour shortages at a facility. There are not enough people to identify and nurse the sick ones.
“We still do a poor job of finding cattle that are sick with respiratory disease,” he said.
“Sometimes we underestimate the number of people that are required to get the job done.”
Feedlots with fewer deaths commonly have more staff to monitor and treat cattle.
He also advocates clean equipment, clean places for animals to lie down, weather protection, clean feed and fresh water.
Antibiotics alone are not enough, he said.
Also, cattle will hide sickness because they are prey animals and hardy.
However, after they arrive at a slaughter plant, lung lesions show which animals were sick. One-third of the cattle with damaged lungs presented severe lesions. Those cattle do not gain as much. When cattle with lung lesions were compared to those with no lung lesions, there is a 43-pound advantage for the no-lesion group.