Poor sanitation and ventilation jeopardize the health and performance of calves on accelerated-growth programs.  “Under highly challenging conditions, young animals on high protein diets are at higher risk of dying,” says Howard Tyler, associate professor of animal science at IowaStateUniversity. As evidence, Tyler points to a Journal of Dairy Science study published earlier this year.

During the study, researchers exposed 120 bull calves to bedding contaminated with coronavirus. They fed half of the calves a conventional milk replacer. The other half participated in an accelerated growth program. Morbidity, measured as the number of days that calves had diarrhea, increased 53 percent for the accelerated calves. Death loss also was higher among the accelerated calves. By two weeks of age, 14 calves on the accelerated program died. In contrast, only three calves on the conventional milk replacer program died during the first two weeks of age.

Poor ventilation also compromises the success of calves on accelerated programs. Tyler’s research group at IowaState reported higher death loss in “compromised” calves on an accelerated program.

During the study, the researchers housed calves in an older, poorly ventilated barn. The conditions were not as bad as those of the coronavirus-challenged calves, Tyler says. Still, seven of the 29 calves on an accelerated program died during the second week of life. Only one out of 14 calves on a conventional milk replacer died at 54 days of age.

Growth rates in both treatments groups were hurt by the marginal facilities, also. “Average daily gains were 1.45 pounds per day for the accelerated program calves and 1.15 pounds per day for conventionally fed early-weaned calves,” says Tyler. These rates of gain were far less than what these calves were genetically capable of gaining.

“Well-managed calves in good facilities should be capable of growing more than 2 pounds per day,” Tyler says. To achieve this growth rate, these calves actually need the higher level of protein provided by accelerated programs. However, some facilities or other management factors can restrict the calf from growing rapidly. In these situations, the “extra” protein fed to calves in an accelerated-feeding program may actually increase the risk of health problems, Tyler adds. 

Bottom line: If you use an accelerated program, maintain excellent sanitation and ventilation.

“It does appear that calves raised under marginal sanitation conditions or in facilities with marginal ventilation have a greater risk of dying, especially during the second week of life when intake levels of milk replacer are dramatically increased in some programs,” Tyler says.

Source: “Practical Economics of Pre-weaning Feeding Programs for Calves,” Howard Tyler, Iowa  State  University; and January 2006 Journal of Dairy Science.