After calves are weaned and being backgrounded, monitor the calves for signs of sickness. Gerald Stokka, former Kansas State Extension beef veterinarian and current senior veterinarian with Pfizer Animal Health, says in most cases the cause of treatment failure is usually due to not treating an animal early enough during the course of the illness.

To that end, Stokka says, "It is important to recognize the behavior of healthy animals." For instance, he says healthy animals should be bright eyed, have a good hair coat, demonstrate curiosity, and be grooming themselves and others.

Appetite can also be a big indicator. "Bunk management is critical. A lot of times with high performing calves the temptation is to feed the daylights out of them. But we can push calves too much and create respiratory disease by the way we feed them. So it is important to monitor historical feed intakes."

Calves with droopy ears, dull haircoats, poor appetites, runny eyes and nose should be pulled, have their temperature taken and be further evaluated and treated if necessary. Stokka points out that 101.5 degrees F is the normal temp for a calf, however in feeding situations, up to 103 degrees can be considered normal for a calf because environmental temperatures can influence rectal temperatures of calves. Thus, on a hot day, calves might have a slightly higher temperature.

To gauge an animal's response, monitoring temperature alone after treatment isn’t enough, according to Stokka because a fever may persist for a few days after treatment. Instead, weight gain is one of the most important things to pay attention to. (Thus it is a good idea to have scales on your chute.)
"If the animal is back on feed and gaining after treatment, that’s the best indicator," Stokka says.

Parasites can also be a factor that suppress appetite and the immune system, so be certain parasite control is part of the health program both at the ranch and in the feedyard.