BRD Clinical Diagnosis Flashcards
What is the prevalence of BRD in Pre-weaning (Cow-Calf)?
- ~20% of herds impacted
- Within herd prevalence 5-15%
What is the prevalence of BRD in Post-Weaning (Stocker/Feedyard)?
- Almost all operations impacted
- 16.2% feedyard cattle treated for BRD
- Avg Cost / case = $23.60
What are the factors that contribute to the development of BRD?
What are the Viral Pathogens that cause BRD?
- Bovine Herpesvirus-1 (BHV-1; IBR)
- Bovine Viral Diarrhea (BVD)
- Bovine Parainfluenza virus type 3 (PI-3)
- Bovine respiratory syncytial virus (BRSV)
- Gen characteristics:
- infectious, contagious
- influence host response to additional pathogens
What is BHV-1; IBR? Reservoir? Transmission? Clinical syndrome?
- Reservoir - Cattle
- new introductions / shedding latent virus
- Transmission - highly contagious
- oro-nasal secretions
- aerosol
- Clinical Syndrome:
- Mild to severe
- Tracheitis
- +/- ocular involvement
- Potential for reproductive impact in breeding stock
What is Bovine Viral Diarrhea virus (BVD)? Reservoir? Transmission?
- Highly mutable RNA virus (pestivirus)
- Multiple genotypes and phenotypes
- Reservoir - Cattle
- Transient infections
- Persistent infection (PI)
- Transmission - Highly contagious
- oro-nasal secretions
- vertical transmission
How are persistently infected BVD cattle made? What are they?
- Calf (fetus) exposed through the dam at day 40-130 of gestation
- May appear normal
- Shed virus constantly
What is the Clinical syndrome of BVD?
- Mild to severe
- Immunosuppression
- Syndromes related to age / cattle class:
- Scours (young calves)
- BRD
- Reproductive
- Mucosal Disease
What pathology is develops from exposure to BVD and/or Mannheimia hemolytica
What is Bovine Respiratory Syncytial Virus? Reservoir? Transmission? Clinical Syndrome?
- Pneumovirus - multiple strains
- Reservoir- Cattle
- young cattle more susceptible
- Transmission - contagious
- oro-nasal secretions
- aerosol transmission
- Clinical Syndrome
- Pyrexia
- Acute Respiratory Distress
- Bronchiole constriction
- Emphysema
- Wet, heavy lungs
- Nasal Discharge
What are the bacterial pathogens that cause BRD? general characteristics?
- Mannheimia haemolytica
- Pasteurella multocida
- Histophils somni
- Mycoplasma bovis
- Gen Characteristics:
- Augment pulmonary damage
- Reservoir - cattle
What is Mannheimia haemolytia? Reservoir? Transmission?
- Agent:
- Gram (-) bacteria
- Formally known as Pasteurella haemolytica
- Serotypes 1 & 2 +/- leukotoxin
- Reservoir - Cattle
- Commensal
- Normal inhabitants of nasal pharyngeal mucosa (tonsillar crypts)
- Transmission - Questionable contagious nature
What is the clinical syndrome of Mannheimia haemolytica?
- Leukotoxin causes pulmonary damage and systemic signs
- Acute and chronic illness
What is Pasteurella multocida? Reservoir? Transmission? clinical syndrome?
- Gram negative bacteria
- Reservoir: cattle (commensal)
- Transmission: Questionable contagious nature
- Clinical syndrome:
- May cause fibrinous pneumonia in chronic cases
- Acute and chronic illness
What is Mycoplasma bovis? Reservoir? Transmission? Clinical syndrom?
- Agent:
- Mollicutes class
- >102 species of mycoplasma
- Reservoir: Cattle (nasal passages)
- Tranmission:
- Oro-nasal
- Aerosol
- Clinical Syndrome:
- Opportunistic organism
- Slow growth ⇢ chronic disease (abscesses)
- Multiple presentations:
- Respiratory
- Arthritis / tenosynovitis
- Ear infections
- Mastitis
What is the epidemiology of Acute Interstitial Pneumonia (AIP)
- 72% feedlots have AIP
- affects 2.8% cattle
- Sporadic occurrence
- More common in heifers
- Later in feeding period (>60d)
- avg days at death 114-136
- Higher rates in summer
- High case fatality (near 100%)
What is the Etiology of Acute Interstitial Pneumonia (AIP)
- Questionable association with common microbial pathogens
- Unknown: dust, allergies, toxicity
- Pneumotoxic effects of 3 methlindole
- Multiple factors
What are the clinical signs of AIP
- Rapid disease onset - often fatal
- Respiratory signs, but no fever
- Open mouth breathing
- May be found dead in pen
- Nasal, oral discharge
What is the pathology of AIP
- Bronchiole constriction - lungs fail to collapse
- Marked interlobular emphysema
- Marked interlobular edema
- Heavy, wet lungs
How long does it take calves to get sick post infectious agent challenge
What biophysical profile changes occur early in BRD?
- Minimal changes in respiratory/heart rates
- Complete blood count (CBC)/Chemistry panel
- few meaningful changes
- Inflammatory profile
What are the common clinical signs of BRD? additional signs?
-
DART:
- Depression
- Anorexia
- Respiration Increased
- Temperature
- Coughing
- nasal discharge
- Isolation from group
What is the accuracy of Visual observation at diagnosing BRD?
- Low
- Sensitivity - 27-63%
- Specificity - 63-92%
When should be recommend ranchers observe their cattle?
- At feed time (convenience) AND
- At times of decreased social pressure (i.e. everyone else is eating so I should eat, everyone is moving to the other side of the pen so I need to move)
