With rising temperatures, moisture is declining and dust is rapidly increasing. Dust in a feedlot can be harmful to the cattle. There are many methods of transmission for feedlot diseases, but a major method is through horizontal transfer in dust particles. These particles can be in the form of expiratory droplets, which are expelled from coughing and sneezing and cause common colds, or these particles can be in the form of droplet nuclei. Droplet nuclei are very small infected droplets that can be spread despite physical separation between animals, often spread through ventilation systems or by wind.
A major disease caused by the spread of droplet nuclei in a feedlot is bacterial pneumonia. Pneumonia is caused by pathogens that are present in the normal flora of cattle. However, a trigger is needed for thee pathogens to cause a disease. Feedlot pneumonia (BRD) risk factors include stress from weaning, shipping, or other external factors, ration changes or transitions, weather, dehydration, stress from processing, and many other factors. Common symptoms of pneumonia in a feedlot animal are depression, poor gut fill, isolation, fever, low head, lethargic, rapid breathing (can often hear the heavy breathing clearly), and nasal discharge. Having qualified employees are key to detect and respond to these signs early on. If animals with pneumonia are not treated rapidly, there is a risk in decreased ADG, increased feed to gain conversion, poorer carcass quality, and mortality. Take the time to familiar yourself and your employees with the common symptoms and establish proper protocols for animal treatment and disease prevention.