The monster we don't see: subclinical BRD in beef cattle

Griffin, Dee

doi:10.1017/s1466252314000255

Cited by 36 publications

(28 citation statements)

References 15 publications

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“…The economic impact of subclinical histophilosis is largely unexplored, in spite of its likely importance (Kennedy et al 1960). An experienced food animal veterinarian remarked recently, in the context of BRD complex, that subclinical disease is the monster we don't see (Griffin 2014). This is due to the practical difficulties of attempting to follow specific cohorts of cattle through slaughter for sampling and testing, and matching those findings to those in individual animals, treated and untreated at the feed yard.…”

Section: Cattlementioning

confidence: 99%

Histophilosis as a Natural Disease

O’Toole

Sondgeroth

2015

Current Topics in Microbiology and Immunology

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Histophilus somni is responsible for sporadic disease worldwide in cattle and, to a lesser extent, in small ruminants, bighorn sheep (Ovis canadensis), and North American bison (Bison bison). The importance of H. somni diseases can be attributed to improved clinical and laboratory recognition, combined with the growth in intensive management practices for cattle. Although outbreaks of bovine histophilosis can occur year-round, in northern and southern hemispheres, it is most frequent in late fall and early winter. Weather, stress, dietary changes, and comingling of cattle are likely to be major triggers for outbreaks. The most frequent clinical expressions of histophilosis include undifferentiated fever, fibrinosuppurative pneumonia, encephalitis-leptomeningitis, necrotizing myocarditis, and diffuse pleuritis. Neurological disease occurs either as thrombotic meningoencephalitis (TME) or as suppurative meningitis with ventriculitis. Acute myocarditis is characteristically necrotizing and generally involves one or both papillary muscles in the left ventricular myocardium. Biofilm-like aggregates of bacteria occur in capillaries and veins in myocardium, in the central nervous system, and on endocardial surfaces. H. somni is a component of bovine respiratory disease (BRD) complex. In our experience, it is most commonly diagnosed in subacute-to-chronic polymicrobial pulmonary infections in combination with Mannheimia haemolytica, Trueperella pyogenes, Pasteurella multocida, or Mycoplasma bovis. Other, less common forms of H. somni disease present as polyarthritis/tenosynovitis, abortion with placentitis and fetal septicemia, epididymitis-orchitis, and ocular infections. It is likely that H. somni is under-recognized clinically and diagnostically. Most state and provincial laboratories in North America rely on bacterial isolation to confirm infection. The use of more sensitive detection methods on field cases of histophilosis will help resolve the pathogenesis of H. somni in natural outbreaks, and whether the disease is as common elsewhere as it is in Canada.

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Section: Cattlementioning

confidence: 99%

Histophilosis as a Natural Disease

O’Toole

Sondgeroth

2015

Current Topics in Microbiology and Immunology

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“…Bovine respiratory disease (BRD) is considered to be one of the most economically important diseases affecting feedlot cattle (Griffin, 2014). Despite attempts to reduce the morbidity and mortality of the disease through management practices and vaccination programs, little progress has been made to lower the in- ABSTRACT: Bovine respiratory disease (BRD) is an economically important disease of feedlot cattle that is caused by viral and bacterial pathogen members of the BRD complex.…”

Section: Introductionmentioning

confidence: 99%

“…Unlike clinical BRD, the prevalence of subclinical BRD has not been well documented. However, it has been suggested that subclinical BRD infection is common, primarily because the correlation of lung lesions in harvested cattle with cattle diagnosed with BRD is low (Griffin, 2014). Common findings at harvest include lung consolidation, in which the lung alveoli are filled with fluid or tissue, and the presence of interstitial fibrinous connective tissue that can lead to fibrosis.…”

Section: Introductionmentioning

confidence: 99%

Rapid Communication: Subclinical bovine respiratory disease – loci and pathogens associated with lung lesions in feedlot cattle1

Kiser

Lawrence

Neupane

et al. 2017

Journal of Animal Science

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Bovine respiratory disease (BRD) is an economically important disease of feedlot cattle that is caused by viral and bacterial pathogen members of the BRD complex. Many cases of subclinical BRD go untreated and are not detected until slaughter, when lung lesions are identified. The objectives of this study were to identify which BRD pathogens were associated with the presence of lung lesions at harvest and to identify genomic loci that were associated with susceptibility to lung lesions as defined by consolidation of the lung and/or the presence of fibrin tissue. Steers from a Colorado feedlot ( = 920) were tested for the presence of viral and bacterial pathogens using deep pharyngeal and mid-nasal swabs collected on entry into the study. Pathogen profiles were compared between cattle with or without lung consolidation (LC), fibrin tissue in the lung (FT), a combination of LC and FT in the same lung (lung lesions [LL]), and hyperinflated lungs (HIF) at harvest. Genotyping was conducted using the Illumina BovineHD BeadChip. Genomewide association analyses (GWAA) were conducted using EMMAX (efficient mixed-model association eXpedited), and pseudoheritabilities were estimated. The pathogen profile comparisons revealed that LC ( = 0.01, odds ratio [OR] = 3.37) and LL cattle ( = 0.04, OR = 4.58) were more likely to be infected with bovine herpes virus-1 and that HIF cattle were more likely to be infected with spp. ( = 0.04, OR = 4.33). Pseudoheritability estimates were 0.25 for LC, 0.00 for FT, 0.28 for LL, and 0.13 for HIF. Because pseudoheritability for FT was estimated to be 0, GWAA results for FT were not reported. There were 4 QTL that were moderately associated ( < 1 × 10) with only LC, 2 that were associated with only LL, and 1 that was associated with LC and LL. Loci associated with HIF included 12 that were moderately associated and 3 that were strongly associated (uncorrected P < 5 × 10-7). A 24-kb region surrounding significant lead SNP was investigated to identify positional candidate genes. Many positional candidate genes underlying or flanking the detected QTL have been associated with signal transduction, cell adhesion, or gap junctions, which have functional relevance to the maintenance of lung health. The identification of pathogens and QTL associated with the presence of lung abnormalities in cattle exhibiting subclinical BRD allows the identification of loci that may not be detected through manifestation of clinical disease alone.

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“…12 Although widely used, treatment records using DART signs are poorly correlated with post-therapeutic prognosis. 13 Accurate prognosis of BRD at the time of treatment is crucial for effective management (drug selection, sorting). To improve accuracy of diagnosis, early detection, and prognosis of BRD, new methods and technologies have been developed recently .…”

mentioning

confidence: 99%