By Gayle Smith

Weaning calves is similar to sending a child to kindergarten for the first time. “Weaned calves have to cope with social stressors to adjust to a new environment,” according to Clint Krehbiel, who is the head of the animal science department at the University of Nebraska. “These social responses become physical responses and influence how they metabolize.” Krehbiel discussed ways to reduce stress in weaned calves during a Ranching for Profitability meeting in Gordon, Nebraska.
 During weaning, calves are separated from their mothers, exposed to new feed sources, and new ways of getting feed and water. “They also have to establish a new social dominance, similar to what happens when your child goes from elementary school to middle school or from middle school to high school,” he says.
“Ranchers need to do what they can to make sure their weaned calves can mount an adequate immune response during times of stress,” Krehbiel continues. Preweaning factors like prenatal nutrition, colostrum intake, BVDV-PI, health, and preshipping management can all influence immunity and subsequent feedlot health, performance and carcass quality. Postweaning factors like transportation, commingling, receiving management and diet, and metaphylactic treatments can also have an impact, he states.
Krehbiel says in Oklahoma, where he was formerly employed at the University, more than two million stocker calves are shipped from out of state to graze on wheat growth pasture each fall and winter. Order buyers put smaller lots of cattle together at an order buying facility and ship them into the state. “Oklahoma gets a lot of co-mingled calves. Once, we were loading 100 calves and I identified 13 different salebarn tags among those 100 calves. That is the definition of co-mingling. Those calves were exposed to a lot of new pathogens.”
The industry needs to find ways to identify high risk calves, rather than mass treating all of them, Krehbiel says. Finding management practices to reduce death loss and morbidity are crucial. Despite new techniques in handling feedlot cattle, better educating pen riders, and improved nutrition and health, mortality continues to increase in the feedyards, he says. “Most is from respiratory diseases like shipping fever and pneumonia,” Krehbiel says.
Some adjustments that could be made during the weaning phase of production may help calves perform better in the feedyard. “The weaning strategy you use alters behavior, but it has minimal impact on performance over a 28-70 day period,” he explains. “The number one practice I would like to see more producers do is to wean their calves, and hold them on the ranch for 30-45 days. I think the best animal husbandry practices are finding ways to eliminate stress in calves, and I would encourage all of you to set a goal of finding ways to reduce risk for clinical disease and enhance performance and carcass merit in these calves,” he says.
Management practices he encourages producers to evaluate on their own operations are weaning methods, preconditioning, vaccinating, castrating, dehorning, nutrition, cattle handling, and transportation. Preconditioning calves can help alleviate weaning and shipping stress, while reducing health costs, he explains.
From a feedlot perspective, Krehbiel says timely castration and dehorning were listed as the number one factors that could help calves perform better in the feedlot. Other factors were BRD vaccines given two weeks before weaning, BRD vaccines given at weaning, weaning and holding the calves for four weeks before shipping them to a feedlot, and bunk breaking calves. When calves get sick in the feedlot, the days they are on feed will go up, and other factors like daily gain, feed efficiency, and dry matter intake go down. “In high death loss pens, it reduces performance,” he explains.
Krehbiel sees advantages to bunk breaking calves. “Calves that are bunk broke before they are shipped have advantages in gain, feed intake, and feed efficiency. Feed intake is the single most important factor affecting the production of feedlot cattle,” he explains. “Low feed intake makes the correction of nutritional deficiencies difficult, which could further compromise immune function and potentially increase the susceptibility to infection,” he says.
When dry matter intake in sick calves is significantly reduced, it impacts performance in the feedlot. “What we would like to see is a weaned calf consuming at least 2 ½ percent of its body weight in dry matter intake as soon as possible after its arrival,” he says. In one study, Krehbiel says dry matter intake in a healthy calf, on days zero through seven after receiving, was 1.55 percent, compared to 0.90 percent in a sick calf.
“Unstressed cattle typically consume feed in quantities sufficient to maintain adequate energy intake,” he explains. “In stressed cattle, voluntary intake of low energy diets is less than that of high energy concentrate diets. Given a choice, stressed calves selected diets with 72 percent concentrate during the first week of arrival. Performance by newly received stocker calves is typically optimized with higher concentrate diets,” he adds.
The animal scientist tells producers there are economic benefits to weaning and holding calves. “It decreases cattle stress and shrink, improves immune function, and gives us less reliance on metaphylaxis and ancillary therapies. It also increases body weight and subsequent performance, which increase marketing opportunities and keep our operations sustainable.”