Small Ruminants: Disease of Adult Sheep- GI and Respiratory

Question 1

What dental disease can be in adult sheep?

Answer 1

Incisors- broken mouth
Molar teeth- uneven wear, sharp edges (painful and difficult to eat)

Question 2

How can sheep be aged using incisors?

Answer 2

Permanent incisors erupt in the order from central to peripheral from 1-4 years

Question 3

What does this image show?

Answer 3

A ewe with broken mouth

Question 4

How should a ewes mouth be examined for dental disease?

Answer 4

Palpation externally- jaw, lymph nodes, face, halitosis, external palpation for pain
Gag and torch internally
Radiography

Question 5

What is quidding a sign of?

Answer 5

Molar teeth disease

Question 6

What causes dental disease in sheep?
What is the solution?

Answer 6

Ageing, Peridontal disease
(bacteria, maloccluson, diet)

Cull
Sedation-rasp (pet sheep)

Question 7

What are the agents for the followind diseases?
* Wooden tongue
* Lumpy jaw
* Calf diptheria (necrotic stomatitis)

Answer 7

Wooden tongue- Actinobacillosis lignerisei
Lumpy jaw- Actinomycosis bovis
Calf diptheria- Fusoforum necrophorum

Question 8

What can cause pharyngeal trauma?
What is the normal history and clinical signs?
Prognosis?

Answer 8

Dosing guns- common
History- few days, weeks after drenching
Clinical signs- dull depressed, inappetant, halitosis, pain
Prognosis- poor

Question 9

1. What is the agent of Johne’s disease?
2. How is it spread
3. When is the key risk period?
4. Where does the disease replicate?
5. When does clinical disease affect sheep?

Answer 9

1. Mycobacterium avium paratuberculosis
2. Spread faecal oral- faeces, colostrum, in utero
3. First 3-4 months of life
4. Replicates in GI lymph nodes and gut- long incubation
5. Typically 3-4 years old

Question 10

What is the pathology of Johne’s disease?

Answer 10

• Cellular infiltration, thickening of intestines
• Malabsorption and protein losing enteropathy
• Hypoalbuminaemia

Question 11

What are the clinical signs of Johne’s Disease?

Answer 11

• Weight loss
• Anaemia
• Bottle jaw
• Sheep over 1 yo
• High parasite burdens
• Non-specific- suspicious high culling rate of thin sheep

Question 12

How is Johne’s disease diagnosed?

Answer 12

• Complex- tests have low sensitivity
• Post mortem- gold standard (enlarged distal mesenteric lymph nodes)
• Serology ELISA antibody- low sensitivity, good specificity
• PCR faeces- intermittent shedding
• Faecal culture- specific, time consuming

Question 13

What does high/low sensitivity mean?
What does high/low specifcity mean?

Answer 13

High sensitivity- few fale negatives
Low sensitivity- high false negatives

High specificity- few false positives
Low specicifity- high false positives

Question 14

How would Johne’s be diagnosed with one clinical case or flock testing?

Answer 14

Clinical case with clinical signs- Faecal PCR, ELISA, PM

Flock tests- select older thinner ewes >3 yo, PCR faecal antigen or with PCR

Question 15

Can Johne’s be successfully be vaccinated against?

Answer 15

Vaccine available Gudair (Virbac)
Does not prevent infection but reduces clinical cases and excretion of bacteria
All lambs 4 and 16w
Repeated anually

Question 16

How can Johne’s disease be managed?

Answer 16

• Lamb older and thinner ewes away from younger, keep seperate until lambs 6 months old ideally
• Lambing hygiene- low stocking, clean bedding, dag
• Test and cull suspect/confirmed

Question 17

What is the SRUC- how can it assist in Johne’s?

Answer 17

Scotlands Rural College
Johne’s disease risk level accreditation programme

Question 18

What is redgut?
What are the clinical signs?

Answer 18

Torsion of intestines
After sudden introduction of lush pasture- legum diet
Sudden death/ recumbent and depressed

Question 19

What are the clinical signs of respiratory disease in sheep?

Answer 19

Weight loss
Coughing
Nasal discharge
Dyspnoea
Sudden death

Question 20

What agents commonly cause respiratory diseases in sheep?

Answer 20

• Chronic supprative pneumonia
• Maedi visna
• Ovine pulmonary adenomatosis
• Laryngeal chrondritis
• Manhaemia haemolytica

Question 21

1. What causes ovine pulmonary adenomatosis?
2. Describe the route of infections
3. What is the incubation period?
4. What are the clinical signs?

Answer 21

1. Jaagsiekte sheep retrovirus- progressive pulmonary carcinoma
2. Virus spreads through lung fluids, aerosol
3. Long- 2-4 years
4. Clinical signs- sudden death, weight loss, increased respiratory effort, excercise intolerance

Question 22

How is ovine pulmonary adenomatosis diagnosed?

Answer 22

• Clinical signs- abnormal lung sounds (crackles, wheezes)
• Ultrasound lung consolidation lesions
• Wheel barrow test- fluid in lungs
• PM for definitive
• No treatment

Question 23

How can ovine pulmonary adenomatosis be controlled for clean and infected flocks?

Answer 23

Clean
* Biosecurity
* Source from farms known history
* Double fencing
* Closed flocks

Infected
* Cull thin or resp signs
* Dont keep offspring for breeding
* Disinfection of housing
* Reduce close contact
* Consider outdoor lambing
* Avoid trough feeding

Question 24

1. What type of disease in maedi visna?
2. Whar are the 2 forms recognised?

What does it cause?

Answer 24

1. Lenti-virus
2. Maedi- chronic resp disease, Visna- neurological

Causes sub-optimal performance/thin ewes and mortality

Question 25

When are sheep infected by maedi visna? How long is the incubation period?

Answer 25

Infected when young- mothers milk/colostrum, lung discharges Long incubation period- several years

Question 26

What are the clinical signs of maedi visna

Answer 26

Clinical signs >2 years usually 4-5 Resp form- weight loss, increased resp effort Neurological- less common, weight loss, abnormal gait, ataxia, paralysis Mastitis- chronic mastitis

Question 27

What is the pathology found of maedi visna? How is it diagnosed?

Answer 27

Pathology Chronic inflammatory lesions in target organ, secondary infection (mannhaemia haemolytica) Diagnosis- Lab tests, Serology (ELISA AGIDT) PM Monitor and cull

Question 28

How can maedi visna be controlled?

Answer 28

Difficult * Test and cull- * Seperate flocks- long term commitment * Conservative- reduce stocking, not housing Prevention- biosecurity, buy accredited sheep

Question 29

1. What is chronic supprative pneumonia? 2. What can cause it? 3. What are the clinical signs? 4. How is it diagnosed? 5. What is the Tx?

Answer 29

1. Lung abscesses 2. T pyogenes- or mixed, Inhalation pneumonia, secondary to pasturellosis infection, spread from elsewhere 3. Often vague- weight loss, cough, nasal discharge 4. Ultrasound, PM 5. Cull

Question 30

1. What is the correct name for 'texel throat' 2. What species and signalment is commonly affected? 3. What is the presentation and what does it lead to?

Answer 30

1. Laryngeal chondritis 2. Mostly beltex and texel- Rams> Ewes> Lambs 3. Loud inspiratory dyspnoea, larynx swollen and obstructed- die of suffocation

Question 31

What is the pathology and treatment of laryngeal chrondritis? How is it controlled? | 'Texel throat'

Answer 31

Texel larynx shorter in length and height, vocal cords closer and narrows to a funnel shape Tx- early, corticosteroids, broad spectrum long term ABs, temporary tracheostomy possible May not recover, may recur Control- don't breed from affected rams

Question 32

1. What is the correct name for pink eye in sheep? 2. What is the common pathogen? 3. When does spreading occur? 4. What is the treatment?

Answer 32

1. Ovine infectious keratoconjunctivitis 2. Mycoplasma conjunctivae 3. Mixing of sheep, tupping time or feeding- some animals carriers, repeat infections common 4. Tx- Isolate affected, look at risk factors for close contact, LA oxytet IM, plus topical eye antibiotics

Question 33

1. What causes and is associated with silage eye? 2. How does the sheep present? 3. How is it treated?

Answer 33

1. Listeria monocytogenes- associated with feeding baled silage in ring feeders 2. Blephrospasm, cloudiness cornea, swollen, folde iris, material front of eye chamber 3. Sub-conjunctival oxytet and dexamethasone, systemic penicillin- remove source

Question 34

Why are thin ewes a welfare and economic concern?

Answer 34

Poor welfare- undernutrition, disease, old age Economics- fertility, low lamb birth weights, twin lamb disease, poor colostrum quality, deaths

Question 35

What are thin ewes DDxs?

Answer 35

* Poor nutrtition- hills ewes over winter, late pregnant, inadequate grazing, poor forage * Teeth/oral lesions * Chronic disease resp- OPA, Maedi-visna, chronic supprative pneumonia, caseous lymphadenitis GI- Johne's, PGE, fluke, phargngeal lesions Lameness

Question 36

How should thin ewes be investigated?

Answer 36

* History- how long, no of animals, stage of production, managment, disease control * Clinical exam- BCS, teeth, lameness, LN * Ultrasound- lungs * Assess nutrtion * Collect samples- faeces, serology, haematology * PM

Question 36

How should thin ewes be investigated?

Answer 36

* History- how long, no of animals, stage of production, managment, disease control * Clinical exam- BCS, teeth, lameness, LN * Ultrasound- lungs * Assess nutrtion * Collect samples- faeces, serology, haematology * PM