Sexten: Respiratory Disease Timing
There are a host of best practices and technologies available to reduce the incidence of bovine respiratory disease (BRD). Covid-19 provides a daily reminder of the management factors influencing respiratory diseases transmission: reduce commingling, decrease stocking density, minimize travel and eat right just to name a few.
Cattle at high-risk for respiratory disease are easy to categorize at arrival even with limited knowledge of their vaccine history due to short weaning, market commingling and shipping stress. Most cattle feeders agree these high-risk cattle provide the greatest management challenge in the first 45 days on the yard.
The alternative to these high-risk calves are “the kind”, you know those with reputation, high growth potential and a well-executed health program. There are few no-risk options in the cattle business but these calves should provide the cattle feeder with relatively fewer health challenges.
A recent article from Applied Animal Science by Miles Theurer and coworkers compared these two cattle types, specifically looking at the timing of BRD relative to arrival. This industry group evaluated the two types of cattle health records from a commercial feedyard.
One may suggest comparing high-risk to high potential cattle as comparing apples and oranges. In reality this is true as the high-risk cattle were categorized as those who received a macrolide antimicrobial on arrival with unknown health history and weaning status and were determined as high-risk by the feedyard and their veterinarian based on shrink, condition, origin and transport distance.
Conversely the high potential cattle were primarily retained ownership calves having been preconditioned and carrying high genetic merit for growth and grade. Specifically the authors indicated the high-potential calves were in the top 25% for growth and 90% choice or better carcass cattle. The minimum health program for high-potential cattle was one modified-live viral vaccine and Mannheimia haemolytica vaccine before arrival to the feedyard. Not to suggest this is a comprehensive preconditioning program but the minimum for inclusion in this comparison.
Clearly two completely different groups of genetics, nutrition and management but a very real and frequent comparison for producers trying to procure and manage feeder cattle inventory at feedyards across the country. Buyers are assigning value to these comparisons in real time with every bid.
The high-potential group experienced less respiratory disease, 12.8% and death loss, 2.5% compared to high-risk cattle at 15.1% BRD and 4.8% death loss. Improved health by high-potential calves with a known health program is not surprising.
The range in health observed across the lots analyzed for each cattle type is worth noting. High-performing calves BRD diagnosis ranged from 2.8% to 36.1% of a lot with mortality ranging from 0 to 7.1%. The range in BRD diagnosis in high-risk calves was wider, 1% to 54.1% with death loss from 0 to 26.8%.
Data like these show it is possible to get lucky with a group of high-risk cattle but the odds are not in your favor. Difficult to know why some high-risk calves remained healthy and some high-potential calves were not. Improvements in communication of previous management from seller to buyer could enhance the odds of correctly assigning health risk and feeder cattle value.
The primary objective of this experiment was to evaluate the timing of BRD onset. Before reading further take a minute to consider the days on feed when you would consider calves past the initial health risk due to their change of address. One step further, would you have different estimates for high-potential compared to high-risk calves?
If we consider 45 days as the point when calf’s risk for respiratory disease begins to decline the findings of this report are surprising. The authors used the data above and looked at the total percent of BRD cases at 45 days to evaluate disease timing. In high-potential calves 33.7% of the BRD cases occurred prior to 45 days of feed. In high-risk groups the cumulative case rate was 67.2% by 45 days on feed.
The high-potential calves performed as expected: faster gaining, more feed efficient and heavier at harvest. Delayed BRD onset in these high-potential calves presents the management challenges associated with increased per head treatment costs due to heavier animals and greater financial risk to death loss later in the feeding period.
Regardless your procurement program managing health should remain a consistent focus throughout the feeding period.
Justin Sexten is vice president of strategy for Performance Livestock Analytics