PA Sheep

Minimum inhibitory concentrations

Minimum Ab conc. required to controll/kill 99% of bacteria

Minimum statutory withdrawal periods

Milk/eggs \= 7d
Meat \= 28d
Fish \= 500C days

Ideal I/M injection site in livestock

Neck

Common causes of ill thrift in sheep

Poor nutrition
PArasitism
Chronic respiratory disease
Dental disease
GI disease
LAmeness
Skin disease (e.g. scab)

Main ddx for severe respiratory disease in sheep

Chronic suppurative pneumonia (abscesses)
Jaagsiekte/OPA
Maedi visna
Laryngeal chondritis
Pneumonic pasteurellosis
CLA (caseous lymphadenitis)
Atypical/non-progressive pneumonia

Treatment of atypical/chronic non-progressive pneumonia in sheep

None - usually self-limiting
Can give antibiotics for secondary infection

Prevention of atypical/chronic non-progressive pneumonia in sheep

Decreased stocking density and stress
Increased ventilation

Causes of chronic suppurative pneumonia in sheep

Inhaled bacteria
Secondary bacterial infection of compromised lung
Haematogenous spread of bacteria
Secondary to M. haemolytica

treatment for Jaggsiekte/OPA

None
Euthanise along with recent offspring

Cause of ovine progressive pneumonia

maedi visna

Diagnosis of MV in sheep

ELISA

Control of MV in a flock

Test and cull
Can artificially rear lambs
Purchase from MVV-free flocks

Treatment of laryngeal chondritis in sheep

Large dose corticosteroid
Broad spectrum antibioticss

Pre-lambing metabolic profiles

2-3 weeks pre-lambing
5 representative ewes per group
Look at albumin, globulin, urea and BHB (ketones)

4 methods for monitoring flock nutritional status

BCS
Weight
Birth weights
Metabolic profiles

Energy requirement of a ewe

8-11MJ
x2 in late preg
x3 in peak lactation

Physiological factors contributing to the development of pregnancy toxaemia

Decreased appetitie, increased energy requirement, altered insulin sensitivity, decreased ability to metabolise ketones

Signs of pregnancy toxaemia

Inappetance
Dull/lethargic
Recumbency
Neurological signs (blindness, star gazing, head tilt)

Blood results in a case of pregnancy toxaemia

Decreased glucose
Increased ketones/BHB
Increased urea, growth hormone and liver enzymes
Decreased calcium and insulin

Treatment for pregnancy toxaemia

s/c (or i/v) glucose or propylene glycol
Oral fluids
Encourage eating
Remove lambs

Prevention of pregnancy toxaemia

Scan and feed accordingly
Good quality roughage for all ewes
Adequate feed face space
Regular BCS
Metabolic profile

When does hypocalcaemia usually occur with ewes

1-3 weeks pre-partum

Signs of hypocalcaemia in ewes

Staggering/weakness
Tremors
Sluggish PLR
Tachycardia
Recumbency
Death

Treatment for hypocalcaemia

Calcium borogluconate
Support to prevent pregnancy toxaemia

Prevention of hypocalcaemia in ewes

Avoid stress
Adequate calcium in diet

Risk factors for hypomagnesaemia in ewes

Use of K+ fertilisers
Rapid grass growth
Cold/wet weather
Ewes with multiple lambs

Signs of hypomagnesaemia in ewes

Sudden death
Hyperaesthesia
Tachycardia
Staggering
Apparent blindness, nystagmus
Recumbency
Paddling
Hypersalivation

Treatment for hypomagnesaemia in ewes

MgSO4 injection

Prevention of hypomagnesaemia in ewes

Concentrates/licks
Boluses
Avoid potash fertilisers in spring

5 stages of flock/herd health planning

Understand the farm
Investigate the problem
Relate findings to farmer
Facilitate decision making
Establish monitoring

In what ways are farm assurance schemes different from flock/herd health plans

Not tailored to individual farm
Strict rules which are checked during annual inspections
No input from farmer

Main ddx for sudden death in adult sheep

Clostridial diseases
Parasitic disease (H. contortus, Fluke)
Respiratory disease (Pasteurellosis)
Poisoning (plants, minerals)

Clostridial diseases

Black leg
Black disease
Braxy
Malignant oedema/Bighead
Abomasitis
Pulpy kidney
Struck
Acute toxic metritis
Bacillary haemoglobinuria
Botulism
Tetanus

Causative agent of black leg

Clostridium chauvoei

Signs of black leg/clostridium chauvoei

Sudden death
Stiffness
Oedema
Crepitus

Treatment of black leg/clostridium chauvoei

Penicillin

PM findings of black leg/clostridium chauvoei

Oedema, emphysema and necrosis of deep muscle masses

Causative agent of black disease

Clostridium novyi type B

How do sheep become infected with clostridium chauvoei/black leg

Injury
Assisted lambing

How do sheep become infected with clostridium novyi type B/black disease

Migration of immature liver fluke

PM findings associated with black disease/clostridium novyi type B

Pale areas of the liver (hepatocellular necrosis) surrounded by darker areas (hyperaemia)

Causative agent of Braxy

Clostridium septicum

How do sheep become infected with clostridium septicum/braxy

Eating frosted food

Signs of braxy/clostridium septicum

Sudden death
Pyrexia
Abdominal pain
Generalised toxaemia

PM findings associated with braxy/clostridium septicum

Severe abomasitis

Causative agents of malignant oedema/bighead

Clostridium septicum/chauvoei/sordelli/novyi type A

Signs of malignant oedema/bighead

Cellulitis \= facial swelling, oedema and emphysema

Treatment of malignant oedema

Penicillin

Causative agent of pulpy kidney

Clostridium perfringens type D

Signs of pulpy kidney/clostridium perfringens type D

Sudden death (esp. good lambs)
Depression
Abdominal pain
Bruxism
Neuro. signs

PM findings associated with pulpy kidney/clostridium perfringens type D

May have no or non-specific lesions - clear fluid in body cavity, petechiae on lungs/epicardium
Typical lesions \= gelatinous clot in pericardial sac, autolytic kidney, cerebellar coning and haemorrhage, glycosuria

Diagnosis of pulpy kidney

PM - toxin in terminal ileum

PM findings associated with death due to severe liver fluke

Haemorrhagic tracts, necrotic liver parenchyma
Haemorrhagic fluid in body cavity

PM findings associated with death due to H. contortus

Pale carcas (anaemia)
Worms in abomasum

Pneumonic form of pasteurellosis in sheep

M. haemolytica (and P. multocida)

Systemic form of pasteurellosis in sheep

Bibersthernia trehalosi

Treatment of pasteurellosis in sheep

Antibiotics (oxytet)
NSAIDs

Signs of pasteurellosis in sheep

Depression, anorexia, pyrexia
Hyperpnoea, dyspnoea
Mucopurulent nasal discharge
Ocular discharge
Congested mm.s

PM findings associated with pasteurellosis in sheep

Ecchymotic haemorrhage of throat/ribs
Subpleural/subpericardial petechiation
Clear, yellow pleural/pericardial exudate
Swollen, heavy lungs

Signs of rhododendron poisoning in sheep

Hypersalivation
Green froth from mouth/nose
Vomiting
Severe abdominal pain

Signs of yew poisoning in sheep

Sudden death (it only takes a few leaves to kill)

Signs of Cu toxicity in sheep

Depression, anorexia
Abdominal pain
Mucoid diarrhoea
Dehydration

PM findings associated with Cu toxicity in sheep

Abomasal inflammation/ulceration
Jaundice
Red/black kidneys
Haemoglobinuria

Diagnosis of Cu toxicity in sheep

Cu content of liver

DDx for sudden death in sheep

Clostridial diseases
Parasites (H. contortus, liver fluke)
Pasteurellosis
Poisoning (plants, minerals)
Anthrax
Accidents (e.g. dosing gun injuries)
Trauma
Stuck/cast on back
Grain overload/ruminal acidosis
Hypocalcaemia/hypomagnesaemia
Intestinal catastrophe (e.g. torsion)
Laryngeal chondritis
Acute gangrenous mastitis

Ddx for ill thrift in ewes

Inadequate nutrition
Supply
Dentition
Lameness
Parasites
Chronic fluke
PGE
Infectious diseases
OPA
Ovine Johne's disease (OJD)
Scab
CLA
MV

Signs of ovine johne's disease

Weight loss (but normal appetite)
Oedema

Causative agent of OPA

Jaagsiekte sheep retrovirus

Signs of OPAq

Weight loss
Exercise intolerance
Tachypnoea
Nasal discharge
Lung crackles

Diagnosis of OPA

Wheelbarrow test

Cause of sheep scab

Allergic dermatitis due to Psoroptes ovis

Signs of sheep scab

Puritis
Alopecia
Weight loss

Diagnosis of sheep scab

Skin scrape
ELISA

Causative agent of caseous lymphadenitis

Cornybacterium pseudotuberculosis

2 forms of CLA in sheep

Superficial form \= abscessation of superficial LNs
Visceral form \= Abscessation of deeper LNs \= ill thrift

Diagnosis of CLA

Isolation of cornybacterium pseudotuberculosis from an affected LN
ELISA

Signs of MV

weight loss
Respiratory signs
Mastitis
Arthritis

Diagnosis of MV

ELISA
PM - rubbery lungs

Ddx for Lameness in sheep

Contagious
Interdigital dermatitis/scald
Footrot
Contagious Ovine Digital Dermatitis (COD)
Strawberry footrot/proliferative dermiatitis
Maedi visna
Foot and mouth
Non-contagious
Shelly hoof
White line disease
Abscesses
Interdigital fibroma
Trauma
Septic arthritis
White muscle disease
(OA, degenerative joint disease, OCD)
(mastitis)
(horn cracks)

Causative agents of Scald/interdigital dermatitis in sheep

Dichelobacter nodosus (severe cases)
Fusobacterium necrophorum (mild cases)

Signs of scald/interdigital dermatitis in sheep

Lameness
Moist, hairless skin

Treatment of scald/interdigital dermatitis

Mild cases (lambs) \= topical antibiotics or 3% formalin footbath
Severe cases (adults) \= Antibiotic injection (oxytet), topical antibiotics/footbath, clean pasture

Causative agent of footrot in sheep

Dichelobacter nodosus

Signs of footrot in sheep

Severe lameness
Black/crumbly debris in the interdigital space
Pungent smell

Why is footrot difficult to get rid of on a farm

Survives for 2w in the environment (6w in foot trimmings)
Some animals can be chronic carriers (recurrent lameness and deformed hooves)

Treatment for footrot in sheep

Long lasting antibiotic injection
Topical antibiotics
Isolate
Do not trim feet

Prevention of footrot on farm

30d quarantine, footbath and examine new arrivals
Do not mix separate groups of animals
Isolate lame animals
Cull recurrent/chronic lameness cases
Vaccination

Signs of contagious ovine digital dermatitis (COD)

Inflammation of coronary band (early infection)
Loose horn (mid-infection)
Deformed horn - club digit

Treatment of COD in sheep

Long acting amoxycillin (2nd line is macrolides)
Anti-inflammatories

Prevention of COD

Quarantine
Isolate cases
Footbath
Footrot vaccine can help

Causative agents of strawberry footrot/proliferative dermatitis in sheep

Dermatophilus congolensis and orf

Shelly hoof signs

Lameness (due to impaction)
Gap between laminae and hoof wall

Treatment of shelly hoof

Careful trimming

Causes of toe granulomas in sheep

Trauma to hoof capsule
Overtrimming
Fb
Secondary to infectious damage

Treatment of toe granulomas in sheep

Dry conditions
Anti-inflammatories
Removal of excess granulomatous tissue
Cautery/copper sulphate/formalin to prevent recurrence
Recurrence common

Treatment of white line abscesses in sheep

Trim to allow drainage
Antibiotics
NSAIDs
If late stage - toe amputation

Treatment of interdigital fibromas in sheep

Surgical removal/cautery
(?increase exercise?)

Signs of septic arthritis

Lameness
Hot, swollen, painful joints
Can see sporadic cases or outbreaks
Associated with navel ill in lambs

Common causative agents of septic arthritis in sheep

Strep. dysgalactiae
Erysipelothrix
E. coli
Trueperella pyogenes
Mannheimia haemolytica
Staph. aureus
Fusobacterium necrophorum

Treatment of joint ill/septic arthritis in sheep

NSAIDs/steroids
Long course of antibiotics (Penicillin, Amoxicillin, fluorfenicol)