Introduction
Bovine respiratory disease (BRD) treatment failure can be defined in different ways, and individual veterinarians and producers likely have different thresholds for considering something a failure (Apley, Reference Apley2015). However, from a practical perspective, BRD treatment failure occurs when animals undergoing a treatment regimen for BRD fail to improve after treatment, resulting in chronic illness, requirement for relapse therapy, sale for salvage slaughter, euthanasia or death. When BRD treatment failure occurs, it has direct impacts, which include costs associated with the management of chronically ill animals, such as the medication given for relapse; reduced returns from animals sent for salvage slaughter, loss of the initial investment of the purchase of the feeder animal and feed and other accumulated expenses to death and costs associated with disposal of the carcass. Indirect impacts are also recognized, including infrastructure requirements, and negative effects on animal welfare and employee morale.
Direct impacts
BRD relapse treatment
When animals receiving BRD treatment fail to directly respond and recover, additional treatment for BRD is usually necessary (Apley, Reference Apley2015). Factors that increase the risk of treatment failure have been described (Avra et al., Reference Avra, Abell, Shane, Theurer, Larson and White2017). In the feedlot, care for an animal failing to respond to initial treatment requires identification and separation of the affected animal from pen-mates, movement of the animal through an animal handling facility, diagnosis of BRD relapse, administration of an antimicrobial drug, possibly also with ancillary or supportive therapeutics; recording what was done in the medical record, and returning the animal to the pen of origin directly after treatment, or after the animal has spent one or more days in a hospital or convalescent pen. The direct impact is the sum of the costs associated with each of these steps. The actual cost of a treatment failure varies depending on the price of the various components at the time of the relapse, as has been described for cattle managed with different protocols (Schunicht et al., Reference Schunicht, Booker, Guichon, Jim, Wildman, Pittman and Perrett2007; Abutarbush et al., Reference Abutarbush, Schunicht, Wildman, Hannon, Jim, Ward and Booker2012).
Management of chronically ill animals
While the majority of cattle treated for BRD respond within a few days of the first BRD treatment, or in some cases after one or more additional treatments, some animals develop chronic BRD that is deemed non-responsive to any therapy. In the feedlot, cattle with chronic illness, including chronic BRD, are generally housed in designated pens called ‘chronic’ pens. Ideally, these pens are equipped and managed to provide a comfortable environment with easier access and less competition for feed and water than in a regular production pen. Cattle in chronic pens should be evaluated daily to assess the clinical progression of each animal, so that recovered animals can be returned to a regular production pen, chronically ill animals that are suitable for salvage slaughter and have fulfilled all pharmaceutical withdrawal times can be shipped, moribund or suffering animals can be euthanized, and animals requiring additional time in the chronic pen can be maintained there for a defined time period. This approach generally works well when the number of chronically ill cattle is small and relatively constant, and the personnel assigned to assess the clinical progression of these animals are well trained, and have sufficient time and support to attend to their job duties. However, whenever the occurrence of BRD peaks (generally in the fall of the year in the United States and Canada), it is followed by an increase in chronically ill animals, resulting in overcrowded ‘chronic’ pens and insufficient time and support for personnel to adequately assess the state of each animal. When this situation occurs, it requires direct intervention by a veterinarian and/or supervisor to prioritize the management of the chronically ill cattle. The direct impact is the sum of the costs associated with the management of chronically ill animals. The indirect impact of managing chronically ill animals is the effect on the morale of employees and animal welfare.
Sale for salvage slaughter
Animals with chronic BRD that do not recover and have fulfilled all pharmaceutical withdrawal times may be suitable for salvage slaughter. Compared to euthanasia or death, sale for salvage slaughter may appear to be a substantially better economic outcome. However, in many cases, especially when the non-responsive animal is of relatively light weight, the proceeds received from salvage slaughter of animals with chronic BRD is only 25–50% (or less) of the original purchase cost of the feeder animal. Moreover, the proceeds from salvage slaughter of a lightweight animal generally do not recover the accumulated expenses for feed and other costs that the feedlot has invested since the animal was received. As a result, the direct impact of sale for salvage slaughter is a substantial loss on each affected animal.
Euthanasia/death
The most definitive form of BRD treatment failure is death. This can occur ‘naturally’ as a result of the pathologic and physiologic processes resulting from BRD, or it can result from euthanasia of cattle with chronic disease, or animals that are moribund or suffering. When death occurs, the direct impacts include the loss of money spent to purchase the feeder animal; accumulated feed and production costs to the point of death, including processing, treatment, bedding, and yardage; and the cost of carcass disposal. In addition, there is an ‘opportunity’ cost to the cattle owner when an animal is not marketed when cattle ownership is profitable, and the loss of daily margin for the feedlot until a replacement animal is able to fill the same pen space. The magnitude of these costs varies depending on the underlying value of feeder cattle and feed and production expenses, as has been described for certain management protocols (Schunicht et al., Reference Schunicht, Booker, Guichon, Jim, Wildman, Pittman and Perrett2007; Abutarbush et al., Reference Abutarbush, Schunicht, Wildman, Hannon, Jim, Ward and Booker2012).
Indirect impacts
Infrastructure
In terms of BRD treatment failure, the biggest infrastructure impacts are the requirement for pens to house animals with chronic BRD. In most cases, these are designated pens associated with facilities established for treating cattle (hospital facilities). However, in instances where there are large numbers of animals with chronic BRD, it can be necessary to temporarily use a regular production pen as a ‘chronic’ pen. In addition to pens for chronically ill animals, it is necessary to have access to appropriate infrastructure to ship animals for salvage slaughter and carcass disposal.
Morale of employees
Managing sick animals, including animals with BRD, is a serious responsibility. Trained animal personnel diagnose and treat animals in the feedlot on a daily basis. From the perspective of the employee, successful treatment of a sick or injured animal is a very rewarding experience. However, when treatment failure occurs, it often has a negative effect on employee morale, and the magnitude of this impact is usually greater the more ‘severe’ the treatment failure. For example, the negative impact on employee morale of treatment failure that results in chronic BRD or death is more severe than treatment failure requiring one or two additional treatments for BRD. Management of cattle with chronic BRD seems to have a greater negative impact on employee morale than coping or dealing with animals that die acutely from BRD. This may not be a surprising revelation, but it bears consideration when working with animal health personnel that have to deal with large numbers of chronically ill animals on an ongoing basis. Veterinarians or managers should make sure that employees responsible for the care of sick cattle have adequate protocols, systems, management support, and other resources in place to help them maintain animal welfare. Such support can promote and maintain positive worker morale.
Animal welfare
Animal welfare is a priority throughout the feedlot production system, from the time an animal is received, and at the point when illness is identified and treated. When treatment failure occurs for BRD or any other disease, the probability of an adverse outcome, such as relapse, chronic disease, or death, goes up. Generally speaking, animals with a higher probability of an adverse outcome require closer monitoring to maintain appropriate animal welfare. As noted above, this is particularly relevant and important in animals with chronic disease to make sure that adequate protocols, systems, management support, and other resources are in place to ensure animal welfare.
Antimicrobial exposure
While all impacts of each antimicrobial exposure in cattle treated for BRD on the development of antimicrobial resistance, or the spread of resistance elements in bacteria of importance to animal or human health, are incompletely understood, it is generally believed that lower antimicrobial exposure is a good thing from an antimicrobial stewardship perspective (Teale and Moulin, Reference Teale and Moulin2012). From a veterinary perspective, this approach makes sense as long as efforts to reduce antimicrobial exposure do not lead to significant negative impacts on animal health and welfare. In terms of BRD treatment failure, the impacts on animal health and welfare have been outlined above. However, when BRD treatment failure occurs, it may be necessary to provide additional treatment for BRD, and this usually includes administration of multiple doses of antimicrobials of different classes. As a result, an indirect impact of BRD treatment failure is increased exposure of the animal, and its pen-mates and environment, to antimicrobials, as a result of the effort to support the health and welfare of the animal. While the impact of these exposures is incompletely understood, the potential for harmful exacerbation of antimicrobial resistance is another indirect negative impact of treatment failure. This is yet another reason for the veterinary profession to develop and validate more effective prevention, control, and treatment strategies for BRD.
Conclusion
BRD treatment failure occurs when animals receiving one or more treatments for BRD fail to directly return to health. Treatment failure has several direct and indirect impacts that negatively affect animal welfare, employee morale, and the financial returns to the cattle producer. An understanding of these impacts is necessary to minimize their effects. Continued efforts to develop improved protocols to minimize treatment failure are warranted.
Acknowledgements
The author acknowledges Dr Amelia Woolums, Mississippi State University, College of Veterinary Medicine, for reviewing and providing constructive input on this manuscript.
