Growing Beef Newsletter
October 2025, Volume 16, Issue 4
Dust
Grant Dewell, ISU extension beef veterinarian
The relatively wet summer has ended, and precipitation so far this fall has been sparse. The dry weather has allowed harvesting of crops to get underway, uninterrupted by muddy fields. Although it is easier for us to work cattle and calves when it is dry it is not necessarily great for cattle. When conditions are dry and cattle are milling there is a lot of dust stirred up, which can be harmful to cattle health.
Dust can irritate a calf’s respiratory system, initiating an introduction of viruses and bacteria into the lungs. Typically, dust particles are filtered out in the nasal passages, but if dust particulate matter is small enough, it can reach the lungs. Additionally, excessive dust concentrations can overwhelm the nasal passages and allow larger particles to reach the lungs. In some cases, if calves are open-mouth breathing due to either heat stress or physical exertion, they will be bypassing the nasal tract and more apt to allow dust into the lower respiratory tract. Besides the respiratory system, dust can also cause eye irritation, leading to increased cases of pinkeye in calves.
Typically, we worry about dust in open feedlots where manure rapidly dries out and becomes dust particles. Increasing pen density by fencing off the back portion of the pen can increase moisture on the pen surface from manure and urine. Pens should be well-maintained to prevent manure from building up on the surface before dusty conditions begin. In some cases, sprinklers can be used to keep the pen surface damp.
For cow-calf producers trying to wean calves in a dry lot, dust can be more of a challenge. Newly weaned calves stir up a lot of dust, and reducing pen space can concentrate calves, leading to more transmission of respiratory pathogens. Weaning on pasture can reduce some of the dust, but generally, calves will congregate in certain areas, trampling out the grass and creating a dusty area. Pen maintenance is critical and one of the factors related to the success of a weaning program.
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