Bovine Respiratory Disease Considerations in Young Dairy Calves.

Raising young dairy calves presents many challenges for producers and veterinarians including losses attributable to BRD. This article will discuss several key concepts for practitioners to consider when applying evidence-based medicine for the control and treatment of BRD in young dairy calves. The authors review BRD complex, provide considerations for diagnostic approaches, and discuss research associated with the control and treatment of BRD.

Highly complex respiratory changes in calf / Alterações respiratórias de alta complexidade em bezerro

The bronchopneumonia of calves represents a risk to national supply chain because it is an ecopathy and weakens the more intensive production systems. It is characterized by inflammatory changes in the bronchi, bronchioles, lung parenchyma, and pleura. It is a disease of multifactorial traits called Bovine Respiratory Disease (BRD). The association of infectious agents with host defense and management to which the animal is subjected leads to the emergence of major clinical manifestations of the disease. The clinical evolution of BRD can also have serious secondary changes such as pulmonary edema, sepsis, and pulmonary hypertension, or even be consequent to the involvement of other structures, such as in cases of myocarditis leading to congestive heart failure. Although this report refers to a non-experimental framework, the circumstances that caused the calf to be subjected to a protocol-specific respiratory assessment involving non-routine reviews has made it possible to associate circulatory and respiratory conditions, rarely considered in ruminant clinic. The focus of this report was pulmonary edema. Modern clinical vision requires of the veterinarian work with cost-benefit relation, so that the more accurate and the earlier the clinical diagnosis the less expensive the treatment.(AU)

A broncopneumonia dos bezerros representa um risco à cadeia produtiva nacional por ser uma ecopatia e fragilizar os sistemas mais intensivos de produção. É caracterizada por alterações inflamatórias de brônquios, bronquíolos, parênquima pulmonar e pleura. Por ser uma doença de características multifatoriais é denominada Complexo Doença Respiratória de Bovinos (CDRB). A interação dos agentes infecciosos, a defesa do hospedeiro e o manejo ao qual o animal é submetido determinam as principais manifestações clínicas da doença. A evolução clínica do CDRB também pode apresentar alterações secundárias graves como o edema pulmonar, septicemia e a hipertensão pulmonar, ou mesmo ser consequente ao acometimento de outras estruturas, como nos casos de miocardite que levam à insuficiência cardíaca congestiva. Apesar deste relato referir-se a um quadro não experimental, as circunstâncias de submissão a um protocolo de avaliação respiratória específico, envolvendo avaliações não rotineiras, permitiu a o estabelecimento da associação entre as interações circulatórias e o quadro respiratório, pouco consideradas na clínica de ruminantes. A referência do presente relato foi o edema pulmonar. A visão clínica moderna obriga o médico veterinário a trabalhar a relação custo-benefício e, quanto mais acurado e precoce é o diagnóstico clínico, menos dispendioso é o tratamento.(AU)

Evolving views on bovine respiratory disease: An appraisal of selected control measures - Part 2.

Bovine respiratory disease (BRD) control poses significant challenges to the cattle industry worldwide. The sometimes complex interactions of factors associated with the animal, the pathogen and the environment complicate the implementation of effective control measures. Blanket vaccination or mass medication provides inconsistent control and the effective tackling of BRD will require innovative, evidence-based and targeted interventions which, if employed sensibly, offer useful alternatives for addressing this disease. This review appraises the role of the specific interventions employed in BRD control to assess how our understanding of their role and efficacy has evolved in recent years.

Beef cattle welfare in the USA: identification of priorities for future research.

This review identifies priorities for beef cattle welfare research in the USA. Based on our professional expertise and synthesis of existing literature, we identify two themes in intensive aspects of beef production: areas where policy-based actions are needed and those where additional research is required. For some topics, considerable research informs best practice, yet gaps remain between scientific knowledge and implementation. For example, many of the risk factors and management strategies to prevent respiratory disease are understood, but only used by a relatively small portion of the industry. This is an animal health issue that will require leadership and discussion to gain widespread adoption of practices that benefit cattle welfare. There is evidence of success when such actions are taken, as illustrated by the recent improvements in handling at US slaughter facilities. Our highest priorities for additional empirical evidence are: the effect of technologies used to either promote growth or manage cattle in feedlots, identification of management risk factors for disease in feedlots, and management decisions about transport (rest stops, feed/water deprivation, climatic conditions, stocking density). Additional research is needed to inform science-based recommendations about environmental features such as dry lying areas (mounds), shade, water and feed, as well as trailer design.

The clinical syndrome of BRD: what it is and what it is not.

The clinical syndrome of bovine respiratory disease (BRD) continues to be a major challenge in bovine production systems. We are challenged by our ability to predict morbidity in groups of cattle, our ability to accurately diagnose and provide a prognosis for individual cases, and our ability to evaluate the results of preventive and therapeutic interventions in the field when production system data are the sole basis for analysis. However, we are fortunate to have perhaps the highest quantity and quality of negative-controlled, prospective, randomized, and masked clinical trial data for any disease in veterinary medicine. It is nevertheless important to recognize that case definitions in these studies may not be consistent or necessarily externally relevant, and that production data in these studies are often missing.

Control, management, and prevention of bovine respiratory disease in dairy calves and cows.

Incidence rates for bovine respiratory disease (BRD) in dairy cattle have remained essentially unchanged over the last 20 years. Dairy calves are more commonly affected than adult animals, with BRD being the principal cause of death in weaned dairy calves. The lack of progress in controlling respiratory disease demonstrates that there continues to be significant room for improvement in controlling this multifactorial syndrome, and that dairy producers need assistance in applying evolving husbandry practices to improve the health of dairy cattle. Therefore, it seems prudent to focus the management strategies on preventing disease through sound management of the transition period, along with sound vaccination and biosecurity programs.

Challenges and opportunities for managing respiratory disease in dairy calves.

Bovine respiratory disease (BRD) is important for the Ontario dairy industry due to the large economic and welfare costs of this disease. Practical science-based management techniques are needed to control and reduce the risk of this disease. Currently, the emphasis on BRD is focused on early detection of disease and prevention. These areas are important but it is not practical to assume this disease will be eliminated in the near future. It is necessary to determine the best practices for caring for sick animals, monitoring their recovery and making changes to their management to facilitate health and recovery. If management changes can be made for animals that are failing to thrive in a current situation, a more complete recovery may be possible and the welfare and economic costs of BRD may be minimized.

Future of BRD research: an animal health industry perspective.

Industry has made large investments into bovine respiratory disease (BRD) research historically, and will continue to do so, despite the apparent lack of progress, an uncertain regulatory environment, and increased competition for internal resources. Factors such as the growing demand for protein, and the ongoing consolidation and 'technification' of the beef sector globally suggest that the industry will continue to demand interventions that prevent disease, are more efficacious, can be easily administered, and positively affect meat quality. New products must also meet the regulatory requirements of safety and efficacy and anticipate the future needs of the numerous stakeholders in the global food chain. Two obstacles in meeting this challenge are the declining interest in food animal medicine, and BRD specifically, and the reluctance to accept new technology at the consumer level.

BRD research needs in the next 10-20 years.

Despite numerous advances in bovine infectious disease research, bovine respiratory disease (BRD) remains a significant disease threat and a cause of tremendous loss. Renewed efforts and innovative strategies are required to build on the successes of the past to achieve the successes of tomorrow. Continued and improved support of BRD research will prove to be a worthwhile investment. To achieve better coordination and more efficient use of resources, the following supportive actions should be considered. There should be coordination of integrative teams through an over-arching agency (United States Department of Agriculture (USDA)) to provide peer review and priority review for available public research funds. This would include use of development grants (as seed and matching funding) available to public/private partnerships. Testing and validation of new procedures in production settings (providing more than cost analyses) should be strengthened. Publication of studies should be promoted and old links between clinicians, diagnosticians and basic researchers should be re-established. Sets of 'best practices' should be published. Programs to support both basic and applied research through graduate fellowships, residencies, workshops and start-up funding for young research scientists should be strengthened. Sustained funding to train the next generation of research investigators should be addressed as a critical need.

An evaluation of bovine respiratory disease complex in feedlot cattle: Impact on performance and carcass traits using treatment records and lung lesion scores.

The objective of this study was to investigate the effects of bovine respiratory disease (BRD) complex on economically important production traits with the use of health records in combination with lung lesion scores obtained at slaughter. Records from 5,976 animals were used in this study from cattle that were managed in Midwestern feedlots. Average daily gain for 3 different feeding periods (acclimation, on-test, and overall test) along with final BW were evaluated as performance measures. Hot carcass weight, LM area, subcutaneous fat cover, and marbling score were collected at slaughter. All calves were monitored by experienced feedlot personnel and treated according to the specific health protocol of each feedlot. Incidence of BRD was observed at a rate of 8.17%, and lung lesions at slaughter were present in 61.9% of cattle from a subpopulation (n = 1,665). From this group of cattle, the overall incidence of BRD, which was defined as cattle that had lung lesions, that were treated for BRD in the feedlot, or both, was 64.4%. Incidence of BRD in the feedlot decreased ADG during both the acclimation period (0.37 +/- 0.03 kg) and the overall test period (0.07 +/- 0.01 kg). Incidence of BRD also had significant effects on HCW and marbling score with reduction of 8.16 +/- 1.38 kg and 0.13 +/- 0.04, respectively, in treated cattle. The adverse effects on production traits tended to increase as the number of treatments increased. Potential decrease in performance and carcass merit observed in this study were associated with a decline of $23.23, $30.15, and $54.01 in carcass value when comparing cattle never treated with cattle treated once, twice, or 3 or more times, respectively. The presence of lung lesions did not have a significant effect on any of the traits; however, there was an association between the presence of active bronchial lymph nodes and less productivity of feedlot cattle.

Javelin diagrams: applications in veterinary medical decision analysis.

This paper introduces javelin diagrams as an innovative way for depicting the results of medical decision analyses. The methods were used to determine whether, and at which values, blood lactate in Belgian White and Blue or maximum tidal volumes in Holstein calves should be measured before deciding to treat or not a calf suffering from the bovine respiratory disease complex. The different alternatives depended upon the probabilities of survival with and without treatment and upon the costs associated with a possible death, the test and the treatment. The chosen alternative was the one with the lowest expected costs. From data collected on the treated calves, the expected costs of measuring lactate (198.01 euro) and tidal volumes (27.38 euro) before deciding to treat or not were lower than the expected costs of directly treating sick Belgian Blue (215.39 euro) and Holstein (51.55 euro) calves, respectively. The treatment should be applied to sick Belgian Blue calves with blood lactate < or = 7.8 mmol/L and to Holstein calves with a maximum tidal volume > or = 1.81 L. At such test values, the treatment expected costs were lower than the expected costs associated with no treatment of calves with other test values. Probabilistic sensitivity analyses showing benefits in treating animals with a positive test (over not treating the animals with a negative test) were mostly invariant to changes in any cost value but were sensitive to uncertainties in probabilities of survival with or without treatment. The javelin diagrams provided a clear visual indication of such results. They depicted how and by how much the benefits were affected by uncertainties in probabilities, they proposed different information values associated with the chosen alternative, and identified directions for further research.