Bovine Respiratory Disease Overview

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Questions and Answers

What is a consequence of a viral infection of the upper respiratory tract, that precedes bacterial colonization of the lung, in bovine respiratory disease?

Decreased bacterial numbers

Increased bacterial numbers (correct)

Decreased disease severity

Shorter duration of shedding

Which of the following is NOT a characteristic of bronchopneumonia (BP)?

Characterized by fever and depression

Invasion of pathogenic organisms into the lung

Increased mucocilliary apparatus function (correct)

Signs of sepsis

What is the primary distinction between bronchopneumonia (BP) and bronchointerstitial pneumonia (BIP)?

BIP is treated with antibiotics only

BIP is characterized by interstitial lung disease (correct)

BIP is caused by viral infection of the upper respiratory tract

BIP is a sequelae to rumen acidosis and liver abscessation

Which of the following is considered a risk factor for metastatic pneumonia?

Rumen acidosis and liver abscessation (A) Signup and view all the answers

How does viral infection affect the respiratory tract in bovine respiratory disease?

Viral infection increases the susceptibility to opportunistic bacterial infections (A) Signup and view all the answers

What is the primary clinical sign of bronchopneumonia associated with Bovine Respiratory Disease Complex?

Cough (B) Signup and view all the answers

Which bacterium is identified as having the essential virulence factor leukotoxin that targets bovine leukocytes?

Mannheimia haemolytica (B) Signup and view all the answers

What is a significant risk factor for morbidity in stocker/feedlot cattle?

Gender, specifically bulls (B) Signup and view all the answers

Which viral pathogen is NOT listed as a contributor to bovine respiratory disease complex?

Bovine Encephalitis Virus (B) Signup and view all the answers

What is identified as the gold standard treatment for bronchopneumonia in cattle?

Antimicrobials (A) Signup and view all the answers

Which of the following factors increases the mortality risk associated with lower arrival weight in stocker cattle?

20-35% for each hundred weight decrease (D) Signup and view all the answers

Which respiratory clinical sign is characterized by an increase in breathing effort in affected cattle?

Tachypnea (B) Signup and view all the answers

What should be done at least 45 days before shipping in preconditioning feedlot cattle?

Wean (D) Signup and view all the answers

Which pathogen is most commonly isolated from cases of bovine respiratory disease?

Mannheimia haemolytica (C) Signup and view all the answers

What is a common feature shared by the various pathogens involved in bovine respiratory disease complex?

Little variation between pathogens (A) Signup and view all the answers

What is a common clinical sign of necrotic laryngitis in calves?

Moist, painful cough (D) Signup and view all the answers

What is the primary causative agent of necrotic laryngitis?

Fusobacterium necrophorum (D) Signup and view all the answers

Which of the following is NOT a known cause of interstitial pneumonia?

Acute trauma (B) Signup and view all the answers

What is the prognosis for patients with metastatic pneumonia?

Poor with therapeutics generally unrewarding (D) Signup and view all the answers

Which treatment is recommended for necrotic laryngitis?

Antimicrobials and corticosteroids (B) Signup and view all the answers

What occurs during acute respiratory distress syndrome (ARDS)?

Progressive dyspnea and hypoxemia (A) Signup and view all the answers

When does fog fever typically manifest in adult cattle?

Within 2 weeks of a pasture change (A) Signup and view all the answers

Which of the following is a common feature of interstitial pneumonia's pathologic definition?

Bilateral lung infiltrates (D) Signup and view all the answers

What is a significant consequence of removing cattle from pastures due to fog fever?

Handling can precipitate deaths (B) Signup and view all the answers

Which diagnostic method is often sufficient for diagnosing necrotic laryngitis?

Clinical signs observation (C) Signup and view all the answers

Which of the following is NOT a consequence of viral infection of the upper respiratory tract preceding bacterial colonization of the lung in bovine respiratory disease?

Reduced duration of shedding (D) Signup and view all the answers

Which of the following viral infections is NOT listed as a contributor to bovine respiratory disease complex?

Bovine Coronavirus (BCoV) (A) Signup and view all the answers

Which of the following is NOT a characteristic of the viral effect on the upper respiratory tract in bovine respiratory disease?

Increased antibody production (D) Signup and view all the answers

Which of the following is a potential consequence of rumen acidosis in cattle?

Metastatic Pneumonia (B) Signup and view all the answers

What is the primary distinction between bronchopneumonia and bronchointerstitial pneumonia?

Bronchopneumonia is characterized by inflammation of the bronchi, while bronchointerstitial pneumonia involves inflammation of the bronchi and interstitial lung tissue (B) Signup and view all the answers

What is a key characteristic of Mannheimia haemolytica that contributes to its pathogenicity in bovine respiratory disease?

It produces a leukotoxin that targets bovine leukocytes. (D) Signup and view all the answers

Which of the following is NOT typically a risk factor for morbidity in stocker/feedlot cattle?

Prior vaccination history of the cattle. (A) Signup and view all the answers

Why is preconditioning important in feedlot cattle?

It helps cattle adapt to a new environment and reduce stress, thereby decreasing their susceptibility to disease. (D) Signup and view all the answers

Which of the following is a clinical sign commonly observed in cattle suffering from bovine respiratory disease complex?

Increased respiratory rate and effort. (D) Signup and view all the answers

Which of the following Mannheimia haemolytica serotypes is most commonly isolated from BRD cases?

Serotype A1 and A6. (C) Signup and view all the answers

What is the gold standard treatment for bronchopneumonia in cattle?

Administration of parenteral antimicrobials. (A) Signup and view all the answers

Which of the following is a consequence of metastatic pneumonia in cattle?

Development of severe liver abscesses. (C) Signup and view all the answers

Which of the following is a key component of preconditioning in feedlot cattle?

Training cattle to eat from a feed bunk and drink from a water trough. (D) Signup and view all the answers

What is a potential consequence of rumen acidosis in cattle?

Development of liver abscesses. (B) Signup and view all the answers

What is the primary function of leukotoxin produced by Mannheimia haemolytica?

To kill bovine leukocytes, including neutrophils. (C) Signup and view all the answers

What clinical signs are associated with metastatic pneumonia in cattle?

Hemoptysis, epistaxis, tachycardia, tachypnea, and coughing (D) Signup and view all the answers

Which of the following conditions is known to be a precipitating factor for metastatic pneumonia in cattle?

Overcrowded conditions (B) Signup and view all the answers

Which of the following is a characteristic feature of the pathologic definition of interstitial pneumonia?

Bilateral lung infiltrates and diffuse alveolar damage (D) Signup and view all the answers

Which of the following is a known causative agent of necrotic laryngitis in cattle?

Fusobacterium necrophorum (C) Signup and view all the answers

Which of the following treatments is recommended for interstitial pneumonia in cattle?

There is no specific treatment (A) Signup and view all the answers

What is the typical age range for calves affected by necrotic laryngitis?

3-18 months (C) Signup and view all the answers

What clinical sign is commonly observed in cattle affected by necrotic laryngitis due to the inflammation and obstruction in the larynx?

Head and neck extended (C) Signup and view all the answers

What is the common pathway involved in the development of acute respiratory distress syndrome (ARDS) in cattle?

Release of inflammatory mediators and neutrophil accumulation (B) Signup and view all the answers

Which of the following is a factor that can potentially lead to the conversion of L-tryptophan to 3-methylindole (3MI) in the rumen, contributing to the development of fog fever?

Lush green pastures in spring (A) Signup and view all the answers

Which of the following diagnostic methods can be used to confirm a diagnosis of necrotic laryngitis?

Endoscopy or radiographs (A) Signup and view all the answers

Study Notes

Bovine Respiratory Disease (BRD)

BRD is a significant disease complex affecting cattle, with varied presentations.
Learning objectives include describing classifications, identifying infectious agents (viral and bacterial), and discussing risk factors, clinical signs, and treatments for various forms of BRD in different cattle groups (nursing dairy calves, stockers, feedlots).

Bronchopneumonia (BP)

BP is characterized by the invasion of pathogenic organisms into the lungs through the bronchial tree.
Clinical signs of BP typically involve fever, depression, and indications of sepsis.

Bronchointerstitial Pneumonia (BIP)

BIP is a complication of bronchopneumonia, characterized by interstitial lung disease.

Metastatic Pneumonia

This form of pneumonia results from septic embolisms originating from other body locations.
Rumen acidosis and liver abscessation are associated sequelae.
Cattle rations high in rapidly fermentable carbohydrates trigger rumen acidosis and rumenitis. This leads to liver abscessation, and thrombosis of the vena cava.
Septic thrombi form and spread, potentially impacting the caudal vena cava.

Interstitial Pneumonia (AIP)

AIP results from an interstitial reaction, potentially caused by ingestion or inhalation of toxins or allergens, or viral respiratory tract infections.
It is characterized by bilateral lung infiltrates and diffuse alveolar damage.
Viral infection (BRSV, naïve or immunocompromised animals) and feedborne pneumotoxins (3-Methyl Indole, "Fog fever", Perilla Mint ketone, 4-ipomeanol (moldy sweet potato)) are known causes.

Bovine Respiratory Disease: Bronchopneumonia

Viral infection of the upper respiratory tract (URT) often precedes bacterial colonization of the lungs in bronchopneumonia.
This leads to increased bacterial numbers, prolonged shedding periods, and more severe disease outcomes.

Viral-Bacterial Synergy

Viral infections affect the mucocilliary apparatus and immune cell function (macrophages) in cattle.
This results in altered mucus, decreased mucociliary velocity, impaired immune responses, and tissue damage.
Bacterial colonization further impacts the immune response in compromised animals via the altered TLR pathways—increasing neutrophil death and dysfunction.

Bovine Respiratory Disease Complex: Bronchopneumonia

Viruses associated with BRD include Bovine Herpes Virus-1 (BHV-1), Bovine Respiratory Syncytial Virus (BRSV), Bovine Viral Diarrhea Virus (BVDV), Parainfluenza 3 Virus (P13), Coronavirus, and Influenza D.
Bacterial pathogens include Mannheimia haemolytica, Pasturella multocida, Histophilus somni, and Mycoplasma bovis.

BRDC Bronchopneumonia - Clinical Signs

Clinical signs of BRD bronchopneumonia show little variation between pathogens.
Typical signs include fever, cough, anorexia, depression, increased respiratory rate, and reduced milk production

BRDC - Primarily in Calves

Dairy calves are affected mostly before the age of 3 months.
Beef calves are affected during the preweaning and post-weaning phases (under five months and 5 to 8 months respectively).

Nursing Dairy Calves

Incidence data (1991–2007) illustrate that respiratory diseases are a significant source of calf mortality in both pre-weaned and weaned calves, encompassing percentages of 8.4–10.8% and 2.2–2.8% respectively.

Pathogens Associated With Nursing Dairy Calf Disease

Data shows Mycoplasma bovis is a significant pathogen in nursing dairy calves, comprising 50% of total isolates.

Measures to Reduce BRD Risk in Nursing Dairy Calves

Feeding only waste or saleable milk (transition milk) while providing more than 4 liters of milk per day to calves less than 21 days old.
Vaccinating dry cows prior to calving.

Stocker/Feedlot Cattle

Factors triggering BRD in this group include weaning, comingling, transportation, new environments, compromised host immune function, and nutrition.

Common Causes of Morbidity in Stockers/Feedlots

This section compiles data on morbidity and mortality rates associated with various cattle conditions and feedlot capacities.

Stocker/Feedlot Multifactorial Disease Syndrome

Preweaning factors, including prenatal nutrition, colostrum intake and BVD persistence also influence immune function.
Postweaning factors, including receiving period management, stress, and nutrition also affect cattle susceptibility.

Stocker/Feedlot Risk Factors

Arrival weight of the cohort is a risk factor. Lower weight correlates to a higher risk of morbidity and mortality.
Gender (bulls) shows a greater risk of morbidity and mortality compared to heifers.
Arrival month (September-November) is a factor linked to increased risks

Feedlot Cattle Prep Conditioning

Procedures include castration and deworming; weaning at least 45 days before shipping; training to eat from a feed bunk and drink from a water trough.

Stocker/Feedlot Importance of Preconditioning

Preconditioning positively affects average daily gain (ADG), morbidity rates, treatment requirements, chronic disease frequency, and medical costs.

Mannheimia haemolytica Highlight

Mannheimia haemolytica is a Gram-negative, facultative anaerobic rod.
Various serotypes exist, with some being pathogenic and others nonpathogenic commensals.
Serotype A1 and A6 are commonly implicated in BRD cases, while serotype A2 is more frequently found in healthy cattle.

Mannheimia haemolytica: Lipopolysaccharide

A systemic inflammatory response syndrome (SIRS) response is noted upon infection.
Clinical signs include tachycardia, tachypnea, cool extremities, and dark mucous membranes.

Mannheimia haemolytica: Leukotoxin

Leukotoxin is an essential virulence factor.
It binds to cells via CD18, causing the death of bovine leukocytes.
This factor leads to neutrophil lysis and the release of digestive enzymes.

Metastatic Pneumonia: Two Presentations

Chronic weight loss and intermittent fever, coupled with coughing are common symptoms.
Second presentation involves hemoptysis, epistaxis, tachycardia, tachypnea, and coughing accompanied by heart murmurs.

Metastatic Pneumonia: Clinical Findings

Clinical signs of pneumonia can include bloody discharges or abnormal heart sounds.

Metastatic Pneumonia: Ultrasound

Findings could include dilated caudal vena cava.

Metastatic Pneumonia Treatment

Prognosis is typically poor; treatment mostly focuses on supportive care.
Antimicrobials target specific bacteria (e.g., T. pyogenes, F. necrophorum, E. coli)
Nutritional and management changes address acidosis as the condition's root cause.

Necrotic Laryngitis

This is an infection of laryngeal mucosa and cartilage.
Acute or chronic laryngeal contact ulcers are essential for illness progression.
Invasive respiratory commensals often cause the condition, with Fusobacterium necrophorum being a major contributor.

Necrotic Laryngitis: Clinical Signs

Calves between 3 – 18 months of age are affected by overcrowded or feedlot conditions.
Clinical signs involve increased respiratory distress, moist, painful cough, inspiratory dyspnea with stertor and an extended head/neck posture and ptyalism (drooling).

Necrotic Laryngitis: Diagnosis

Usually, diagnosis relies on clinical signs.
Endoscopy and radiographic methods also aid in the diagnosis.
Ultrasound can support diagnosis.

Necrotic Laryngitis: Treatment

Antimicrobials—Florfenicol (20 mg/kg IM q48 hr or 40 mg/kg SQ once).
Corticosteroids —Dexamethasone (0.1 mg/kg IV/IM for 2-3 days).

Interstitial Pneumonias

Interstitial pneumonia is an idiopathic form of acute lung injury characterized by bilateral lung infiltrates and diffuse alveolar damage.

Interstitial Pneumonia (ARDS):

Acute Respiratory Distress Syndrome (ARDS) is noted as acute progressive dyspnea and tachypnea with hypoxemia.

Interstitial Pneumonias: Known Causes

Viral Infection (BRSV naïve or immunocompromised animals).
Feedborne pneumotoxins (e.g., 3-Methyl Indole, "Fog fever", Perilla Mint ketone, 4-ipomeanol (moldy sweet potato)).

Interstitial Pneumonia: Fog Fever

Primarily affecting adult cattle over 2 years of age, the condition is linked to the change in grazing patterns from sparse winter forage to lush spring pastures triggering the conversion and production of 3-methylindole.

Interstitial Pneumonia: Fog Fever: Clinical Signs

The onset is typically noticed within two weeks of changing pastures.
Clinical signs consist of sudden dyspnea with a loud expiratory grunt, frothing/accumulation of secretions in the mouth, open-mouthed breathing and rapid breathing rate.

Interstitial Pneumonia: Treatment

Specific treatment for interstitial pneumonia is lacking.
Prognosis for treatment varies according to the condition extent.
Affected animals may be moved to calmer pastures, supportive care, and if possible, diuretics and corticosteroids may be considered.

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Description

This quiz covers key concepts related to Bovine Respiratory Disease (BRD) and associated forms of pneumonia in cattle. Participants will explore classifications, infectious agents, risk factors, clinical signs, and treatments specific to conditions like Bronchopneumonia, Bronchointerstitial Pneumonia, and Interstitial Pneumonia. Enhance your understanding of these significant cattle diseases.