Deaths from Pneumonia in Feedlot Cattle Increase
Livestock Update, November 2001
W. Dee Whittier, Ext. Veterinarian, Beef Cattle, VA-MD Regional College of Vet. Medicine, VA Tech
Cattle that were placed in feedlots in the major feedlot areas of the US were more likely to die of respiratory disease (pneumonia or shipping fever) in 1999 than they were in 1994, with a continual upward trend in death risk each year. From 1994 to 1999, the death loss percentage rose from 1.03% to 1.42% according to a study published in the Journal of the American Veterinary Medical Association (JAVMA 219:1122-1127, Oct. 15, 2001). This is a 38% increase in death loss risk over the period.
This new information is probably the best information that has ever been available to study death risk in feedlot cattle. It is based on data collected on 21.8 million cattle entering 121 large feedlots over the six years of the study. Data collection for the study was prompted by a USDA study done by directly calling feedlots in 1993. Because feedlots were somewhat protective of their data, a system for submitting records anonymously through veterinarians was developed. This study summarizes the death-loss information from these records submitted for years following the initial study.
The study, as expected, substantiated that respiratory disease was the single biggest cause of death in the feedlots, followed by digestive tract disorders. There was an increased risk of death for cattle entering feedlots in the fall, reaching a peak in December when 1.73 % of cattle entering lots died of respiratory disease. Cattle entering lots in May experienced only a 0.35% risk of dying of respiratory disease. Heifers were significantly more likely to die of respiratory tract disorders in the later years of the study compared to steers.
It is somewhat frustrating that authors of this report suggest little about the cause for the increase. The study states, "The reason for the increase over time in the risk of dying of respiratory tract disease in the present study was unclear." One theory that immediately comes to mind involves the proportion of lightweight calves entering the lots. Since the years involved were a period of decreasing cattle numbers one idea is that feedlots pulled in ever-smaller cattle that were more susceptible to disease. However, the study collected data on entering weights of cattle and documented that the proportion of cattle weighing less than 600 lb. over the period increased only slightly from 27.0% to 28.2%.
So what are the implications for Virginia feeder calf producers of this study? I suggest the following:
This new study documents that, despite more and better vaccines and antibiotics, respiratory disease or shipping fever in cattle is still and important economic issue for which our industry needs to continue to search for solutions.