Adult Sheep: Sudden Death & Ill Thrift Flashcards
what are key performance indicators in a flock concerning ill thrift/sudden death
How many sheep have died/are ill-thriven?
What system are we talking about?
Is the farmer concern/going to do something about it?
Can we do something about it?
How much is going to cost if we do/don’t do anything?
what are diagnostic tools used
Post-mortem:
- Gross pathology
Examine in contact animals
Sampling
Cost
A percentage of animals
what are preventative measures for il thrift/sudden death
Biosecurity (quarantine)
Isolation
Move from incriminated pastures/shed
Reduce stress
- Avoid sudden changes in nutrition/diet
- Mix different age groups
- Overcrowding
- Lack of feeding
Vaccination
- Clostridial diseases
- Pasteurellosis
what is the definition of sudden death and how do you determine if they were just found dead
How often are they checked?
Found dead is better
There may have been clinical signs but they were not seen
BCS
Position of carcass
history (feeding, routine treatments, recent stressful events)
what are the main ddx for sudden death in adult sheep
- Clostridial diseases
- Parasitic disease
- Acute fluke
- Haemonchus contortus
- Respiratory disease
* Pasteurellosis - Poisonings
* Plants and minerals
what are the common clostridial diseases in adult sheep
Blackleg
Black disease
Braxy
malignant edema
Abomasitis
Pulpy kidney (more common dx of sudden death in lambs)
Struck
Acute toxic metritis
Bacillary hemoglobinuria
Botulism
Tetanus
what is the cause of blackleg
C. chauvoei
what are the clinical signs of blackleg if found alive
Stiffness, unwillingness to move, edema and crepitus of hind legs muscle with myositis
how can blackleg be treated if found alive
parenteral penicillin in early cases
what is found on PM with blackleg
Usually greater deep muscle masses (hind and forelimbs)
Edematous and emphysematous
Crepitant, dry, necrotic muscle fibres (dark red/black)
what is the likely cause to these PM changes
black leg
c chauvoei
what is the agent that causes black disease
c. novyi type B
what is black disease associated with
migration of immature liver fluke in the liver
what are the PM changes seen with black disease
Pale areas (hepatocellular necrosis) of variable size and surrounding darker areas (hyperemia)
what is the PM changes seen here and the cause
c. novyi type B
black disease
liver fluke migration in liver
what is the agent that causes braxy
c septicum
what is braxy associated with
frosted food
if the sheep are alive what are the clinical signs of braxy
High fever, abdominal pain, generalized toxemia
what are the PM changes seen with braxy
Severe abomasitis
what is the agent that causes malignant edema (‘big head’)
C. septicum, C. chauvoei, C. sordellii, C. novyi type A
what is the most common etiology of malignant edema
can affect all ages but mostly associated with rams from fighting wounds
what does malignant edema cause
Cellulitis causing massive facial swelling with edema and gas production
what can you treat malignant edema
parenteral penicillin in early cases
what is the agent that causes pulpy kidney
c. perfringens type D
what are the clinical signs of pulpy kidney
sudden death in non immune lambs
what age does pulpy kidney usually affect
4 weeks to 8 month old lambs
often the bigger, better ambs
what are the clinical signs of pulpy kidney if found alive
Severe depression
Abdominal pain
Grinding teeth
Neurological signs (seizures, opisthotonus)
what are the PM findings of pulpy kidney
No gross lesions to very unspecific (clear fluid in body cavities, small petechial hemorrhages on lungs and epicardium) to typical ones (gelatinous clot in the pericardial sac, autolytic kidney, cerebellar coning with hemorrhage, glycosuria)
how is pulpy kidney infection confirmed
Toxin in small intestinal contents (terminal ileum)
Histology of brain
what are the PM changes seeen
pulpy kidney
when is acute liver fluke commonly seen
late summer/autumn
depends on area
how does acute liver fluke cause sudden death
Immature fluke migrating within the liver parenchyma taking up residence within the bile ducts
death as consequence of acute, widespread hepatic necorsis
what are the PM changes seen in acute liver fluke
Hemorrhagic tracts of necrotic liver parenchyma (dark red) and often with fibrosis
what PM changes are seen here
acute liver fluke
when does haemonchosis occur
late summer
what are the PM changes seen with haemonchosis
Examine/collect abomasal content and abomasal mucosa
what are the agents that cause pastuerellosis
- Mannheimia hemolytica (and Pasteurella multocida)*
- Pneumonic form
- Bibersteinia trehalosi:*
- Systemic form
how can pastuerellosis be treated
can attempt antibiotic treatment
long acting oxytetracylcine and NSAIDs
what are the clinical signs of pasteurellosis if found alive
Dullness
Anorexia
Pyrexia
Hyper and dyspnea
Bilateral serous to mucopurulent nasal discharge and ocular discharges, congested mucosa
what are the PM signs seen with pasteurellosis
Ecchymotic hemorrhage of the throat and ribs
Sub pleural and sub-pericardial petechiation
Clear, yellow pleural and pericardial exudate
Lungs are swollen, heavy and cyanotic with frothy hemorrhagic fluid when incised
what are the PM changes seen here
pasteurellosis
what plants can cause sudden death
rhododendron
yew
what are the clinical signs of rhododendron poisoning
Excessive salivation
Greenish froth around mouth and nose
Vomiting
Severe abdominal pain
what is the treatment of rhododendron
Purgatives
Supportive therapy
PM
what does yew poisoning cause
sudden death within 24 hours frmo ingestion
potent cardiotoxic alkaloid
what are the most common breeds affected by copper poisoning
north ronaldsay
charollais
texel
suffolk
least affected are scottish black faced
what are the causes of Cu poisoning
Overdosage with preparations for treatment of Cu deficiency
Feeds with high Cu content:
- Crops grown with use of pig or poultry manure as fertilizer
- Distillery by-products (ex dark grains)
- Cattle and pig feedstuff
what are the clinical signs of Cu poisoning
Depression
Anorexia
Abdominal pain
Mucoid diarrhea
Dehydration and death within 24 hours
what are the PM changes seen with Cu poisoning
From acute inflammation of the abomasal mucosa with ulcerations and hemorrhagic areas to jaundiced, yellow/orange liver, dark red/black kidneys, hemoglobinuria
Tissues with Cu concentrations might not be elevated
Kidney Cu concentration
what are other less common causes of sudden death in adult sheep
Anthrax
- Notifiable
Accidents
- Dosing gun injuries
Trauma
- Dog
Stuck
- Cast on back
Grain overload/ruminal acidosis
Hypocalcemia
Hypomagnesemia
Intestinal catastrophe
Laryngeal chondritis
Acute gangrenous mastitis
what are the main ddx of ill thrift in adult sheep
Inadequate nutrition
- Low BCS across the whole flock
- Poor dentition
- Lameness
Parasites
- Chronic liver fluke
- PGE
Infectious disease
- Ovine Johne’s disease (OJD)
- Ovine pulmonary adenocarcinoma (OPA)
- Sheep scab
- Caseous lymphadenitis (CLA)
- Maedi-Visna (MV)
what is the cause of ovine pulmonary adenocarcinoma
jaagsiekte sheep retrovirus (JSRV)
what is the incubation period of OVA
3-4 years
what are the signs of OVA
Initial weight loss and exercise intolerance
Tachypnea, nasal discharge, harsh lung sounds
how is OVA diagnosed
wheelbarrow test
ultrasound
PM
what could be the causative agent for the pathology seen here
OVA
What causes sheep scab
psoroptes ovis
how is sheep scab transmitted
direct
what are the clinical signs of sheep scab
Pruritus
Severe alopecia
Considerable weight loss
how is sheep scab diagnosed
Skin scraping and ELISA
what is the causative agent of caseous lymphadenitis
Corynebacterium pseudotuberculosis
what does the superficial form of caseous lymphadenitis cause
Abscessation of superficial lymph nodes
what does the visceral form of caseous lymphadenitis cause
ill thrift
how is caseous lymphadenitis diagnosed
isolation of organism from abscesses or ELISA
what causes maedi-visna
maedi visna virus (MVV)
what does maedi visna cause
Chronic, progressive lymphoproliferative disease
what is the incubation period of MVV
clinical disease rare in animals <3 years old
what are the clinical signs of MVV
Weight loss
Exercise intolerance
Progressive tachypnea/dyspnea
how is MVV diagnosed
ELISA
what are the PM signs of MVV
Firm, rubbery, heavy lungs
what could be the causative agent of these pm changes
MVV
