In limiting losses from Bovine Respiratory Disease (BRD), early diagnosis and appropriate treatment play a major role in success. During the BRD conference taking place in Denver this week, several presentations outlined new diagnostic tools, some involving emerging technologies and others simply making better use of existing diagnostic techniques.
University of Wisconsin veterinarian Sheila McGuirk, DVM, PhD, ACVIM, says beef and dairy producers often do not routinely screen calves for respiratory disease. Eventually, producers and veterinarians will have access to comprehensive, practical and affordable respiratory disease screening tools such as accelerometers, pedometers, appetite monitors, feed consumption detection systems, remote temperature recording devices, radiant heat detectors, electronic stethoscopes, and thoracic ultrasound. But until these systems are validated and available, producers can improve their timely diagnosis of BRD by using a standardized scoring system.
McGuirk and her team have developed a scoring system that attributes severity scores to each of four clinical parameters: rectal temperature, cough, nasal discharge, ocular discharge or ear position. A total respiratory score of five points or higher can be used to distinguish affected from unaffected calves. She recommends using the scoring system twice weekly in pre-weaned dairy calves to facilitate early detection. Coupled with effective treatment protocols she says, this scoring system will reduce post-weaning pneumonia, chronic pneumonia and otitis media.
In this clinical signs-based respiratory scoring system, respiratory disease is determined to be present when two or more examination parameters are moderate or severely abnormal. The examination parameters and graded scale evaluation criteria are available online from the University of Wisconsin’s Vetmed website.
The scoring system's points range from 0 to 3 as clinical signs progress from normal (0), to mildly abnormal (1), to moderately abnormal (2) to severely abnormal (3). Calves with a total respiratory score > 5 or that have 2 or more clinical parameters with score 2 or 3 are considered to have respiratory disease. For calves in group pens, the respiratory screening process can be modified, and a form for group pen screening is available from the University of Wisconsin.
McGuirk says a farm’s calf-health screening program should include daily observations, twice-weekly screening tests and a defined exam process. Respiratory scoring is part of the twice-weekly health screening program but also should be applied when workers doing daily observations note individual calves that need a more detailed examination. She recommends setting up daily observations for high-risk calves and those that have shown early signs of BRD but have scored below 5 in the scoring system. She also notes that BRD prevalence increases with age in preweaned calves so strategic use screening of calves just prior to weaning can positively impact the occurrence of post-weaning pneumonia.
Implementing a routine screening process entails some labor costs, but the benefits can pay for a dairy. A University of Wisconsin Extension study indicated that that, on average, one full time equivalent (FTE) employee is needed to perform the routine daily chores for each 100 calves. McGuirk estimates an additional 0.5 FTE is needed for every 100 calves to perform these daily and weekly health screening procedures.
Initially, farms likely will see an increase in number of calves treated, treatment costs, respiratory morbidity and calls to the veterinarian. Mortality rate from BRD however, likely will decline, and over time, the farm will benefit from decreases in calf treatment rate, number of days of treatment, treatment relapses, treatment costs, morbidity and mortality. Over the long term, producers can achieve better productivity and profitability of replacement heifers, better employee morale and motivation and reduced employee turnover.
Veterinarians can work with clients to enter individual calf scoring results into a record system to track performance and cost, monitor disease incidence, analyze treatment efficacy or create valuable health reports. When these records indicate a change in prevalence of respiratory disease, the veterinarian can focus diagnostic testing on the most recent, untreated diseased calves.