Diagnosis of Resp Disease

List the differentials for individuals with resp disease

• Vena - caval thrombo-embolism

• Secondary infections to viral challenge

• Shipping fever

• Fog fever

• Bovine farmer’s lung

• CBPP…notifiable

• Calf diphtheria

• Laryngeal chondritis (beef predilection)

• Chronic suppurative pneumonia

• Diffuse Fibrosing Alveolitis…chronic pathology of unknown/multiple causes; resp. symptoms

What are your top differentials for a group of fattening cattle?

Mannheimiosis/Pasteurellosis

Histophilus somni

What is your top differential for a group of housed calves?

Enzootic pneumonia

What is your top differential for a group of first grazing season heifers?

Lungworm

What is Stertorous upper respiratory noise a pathognomic sign for?

Laryngeal pathology- commonly laryngeal chondritis

What is a profuse nosebleed a pathognomic sign for?

• Vena caval thrombosis…hopeless

• Foreign body (blackthorn prickles)

What are the principles of lab diagnosis of a resp case?

• Only sample if useful/going to affect decision/treatment

• Sample acute cases (before 2° have invaded)

• Be aware of commensals

• URT organisms may not reflect path of LRT

What are some commensals that you should be aware of?

• Pasteurella and Mannhaemia

• URT Mycoplasma

Can all be commensal

What samples can you take for a suspected resp disease and what agents are they useful for?

• Conjunctival swab/scrap

  • IBR (Mycoplasma if eyes affected)

• NP swab

  • IBR, RSV, Pi3

• BAL

  • M. bovis, IBR, RSV, Pi3, BVD, Haemophilus, Lungworm

• Faecal sampling

  • D. viviparus (Baermann)

• Serology (single/paired) 2-3 weeks aparts or rising titre 4- fold

What agents should you use a transport medium for?

• Viral transport medium if requesting virus isolation or at least a plain swab

• Mycoplasma also requires transport medium

Explain how a BAL is performed

• Clean nares

• Insert outer tube then inner

• Inject 60ml of PBS

• Wait 20 secs and withdraw, put in bottle

• Send to lab

What groups samples can be used to diagnose and monitor for resp diseases?

• Bulk milk antibodies

  • Particularly IBR

What is lung scanning used for?

• Prognostic indicator and for monitoring

• Presence of lesions may indicate poor detection

In what location do you perform a lung scan?

• Clip/shave vertically from below caudal scapula to elbow

• Between the rib spaces 5-7

What do you look for to identify pathology on lung scans?

• Normal: Reflection of white pleura and artefacts

• Pneumonic: Hyperechogenic areas (white, looks like scar tissue

What can you examine in the environment which can indicate some risks for resp disease?

• Building (subjective exam)

  • Urea, warm air, underfoot squelch test, are you too hot/cold, dust in air, dusty bedding, temp of bedding feel it

• Objective

  • Stack effect

  • Environmental data loggers for temp and humidity

  • AHDB website calculations

What can be some indicators of whether the stack effect is working?

• Can see both outlet and inlet

• Indications of inadequate

  • Tiger stripes

  • Cobwebs

• Smoke tests (dry straw in metal container, covered with damp)- animals have to be in building

What are some common reasons for lack of stack effect?

• No outlet or building too high

• Insufficient biomass

How can you objectively record respiratory health of calves?

• Respiratory scoring group