Small Ruminants: Disease of Adult Sheep- GI and Respiratory Flashcards
What dental disease can be in adult sheep?
Incisors- broken mouth
Molar teeth- uneven wear, sharp edges (painful and difficult to eat)
How can sheep be aged using incisors?
Permanent incisors erupt in the order from central to peripheral from 1-4 years
What does this image show?
A ewe with broken mouth
How should a ewes mouth be examined for dental disease?
Palpation externally- jaw, lymph nodes, face, halitosis, external palpation for pain
Gag and torch internally
Radiography
What is quidding a sign of?
Molar teeth disease
What causes dental disease in sheep?
What is the solution?
Ageing, Peridontal disease
(bacteria, maloccluson, diet)
Cull
Sedation-rasp (pet sheep)
What are the agents for the followind diseases?
* Wooden tongue
* Lumpy jaw
* Calf diptheria (necrotic stomatitis)
Wooden tongue- Actinobacillosis lignerisei
Lumpy jaw- Actinomycosis bovis
Calf diptheria- Fusoforum necrophorum
What can cause pharyngeal trauma?
What is the normal history and clinical signs?
Prognosis?
Dosing guns- common
History- few days, weeks after drenching
Clinical signs- dull depressed, inappetant, halitosis, pain
Prognosis- poor
- What is the agent of Johne’s disease?
- How is it spread
- When is the key risk period?
- Where does the disease replicate?
- When does clinical disease affect sheep?
- Mycobacterium avium paratuberculosis
- Spread faecal oral- faeces, colostrum, in utero
- First 3-4 months of life
- Replicates in GI lymph nodes and gut- long incubation
- Typically 3-4 years old
What is the pathology of Johne’s disease?
- Cellular infiltration, thickening of intestines
- Malabsorption and protein losing enteropathy
- Hypoalbuminaemia
What are the clinical signs of Johne’s Disease?
- Weight loss
- Anaemia
- Bottle jaw
- Sheep over 1 yo
- High parasite burdens
- Non-specific- suspicious high culling rate of thin sheep
How is Johne’s disease diagnosed?
- 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
What does high/low sensitivity mean?
What does high/low specifcity mean?
High sensitivity- few fale negatives
Low sensitivity- high false negatives
High specificity- few false positives
Low specicifity- high false positives
How would Johne’s be diagnosed with one clinical case or flock testing?
Clinical case with clinical signs- Faecal PCR, ELISA, PM
Flock tests- select older thinner ewes >3 yo, PCR faecal antigen or with PCR
Can Johne’s be successfully be vaccinated against?
Vaccine available Gudair (Virbac)
Does not prevent infection but reduces clinical cases and excretion of bacteria
All lambs 4 and 16w
Repeated anually
How can Johne’s disease be managed?
- 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
What is the SRUC- how can it assist in Johne’s?
Scotlands Rural College
Johne’s disease risk level accreditation programme
What is redgut?
What are the clinical signs?
Torsion of intestines
After sudden introduction of lush pasture- legum diet
Sudden death/ recumbent and depressed
What are the clinical signs of respiratory disease in sheep?
Weight loss
Coughing
Nasal discharge
Dyspnoea
Sudden death
What agents commonly cause respiratory diseases in sheep?
- Chronic supprative pneumonia
- Maedi visna
- Ovine pulmonary adenomatosis
- Laryngeal chrondritis
- Manhaemia haemolytica
- What causes ovine pulmonary adenomatosis?
- Describe the route of infections
- What is the incubation period?
- What are the clinical signs?
- Jaagsiekte sheep retrovirus- progressive pulmonary carcinoma
- Virus spreads through lung fluids, aerosol
- Long- 2-4 years
- Clinical signs- sudden death, weight loss, increased respiratory effort, excercise intolerance
How is ovine pulmonary adenomatosis diagnosed?
- Clinical signs- abnormal lung sounds (crackles, wheezes)
- Ultrasound lung consolidation lesions
- Wheel barrow test- fluid in lungs
- PM for definitive
- No treatment
How can ovine pulmonary adenomatosis be controlled for clean and infected flocks?
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
- What type of disease in maedi visna?
- Whar are the 2 forms recognised?
What does it cause?
- Lenti-virus
- Maedi- chronic resp disease, Visna- neurological
Causes sub-optimal performance/thin ewes and mortality
When are sheep infected by maedi visna?
How long is the incubation period?
Infected when young- mothers milk/colostrum, lung discharges
Long incubation period- several years
What are the clinical signs of maedi visna
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
What is the pathology found of maedi visna?
How is it diagnosed?
Pathology
Chronic inflammatory lesions in target organ, secondary infection (mannhaemia haemolytica)
Diagnosis-
Lab tests, Serology (ELISA AGIDT)
PM
Monitor and cull
How can maedi visna be controlled?
Difficult
* Test and cull-
* Seperate flocks- long term commitment
* Conservative- reduce stocking, not housing
Prevention- biosecurity, buy accredited sheep
- What is chronic supprative pneumonia?
- What can cause it?
- What are the clinical signs?
- How is it diagnosed?
- What is the Tx?
- Lung abscesses
- T pyogenes- or mixed, Inhalation pneumonia, secondary to pasturellosis infection, spread from elsewhere
- Often vague- weight loss, cough, nasal discharge
- Ultrasound, PM
- Cull
- What is the correct name for ‘texel throat’
- What species and signalment is commonly affected?
- What is the presentation and what does it lead to?
- Laryngeal chondritis
- Mostly beltex and texel- Rams> Ewes> Lambs
- Loud inspiratory dyspnoea, larynx swollen and obstructed- die of suffocation
What is the pathology and treatment of laryngeal chrondritis?
How is it controlled?
‘Texel throat’
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
- What is the correct name for pink eye in sheep?
- What is the common pathogen?
- When does spreading occur?
- What is the treatment?
- Ovine infectious keratoconjunctivitis
- Mycoplasma conjunctivae
- Mixing of sheep, tupping time or feeding- some animals carriers, repeat infections common
- Tx- Isolate affected, look at risk factors for close contact, LA oxytet IM, plus topical eye antibiotics
- What causes and is associated with silage eye?
- How does the sheep present?
- How is it treated?
- Listeria monocytogenes- associated with feeding baled silage in ring feeders
- Blephrospasm, cloudiness cornea, swollen, folde iris, material front of eye chamber
- Sub-conjunctival oxytet and dexamethasone, systemic penicillin- remove source
Why are thin ewes a welfare and economic concern?
Poor welfare- undernutrition, disease, old age
Economics- fertility, low lamb birth weights, twin lamb disease, poor colostrum quality, deaths
What are thin ewes DDxs?
- 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
How should thin ewes be investigated?
- 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
How should thin ewes be investigated?
- 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
