Ovine & Caprine Flashcards
Topic: Lupine toxicity
1. What toxic chemical does the lupine plant contain?
2. What c/s are exhibited by acutely affected sheep? Cattle?
3. How can you confirm diagnosis in sheep?
- Quiolizidine alkaloids
- Sheep display neurological signs including ataxia, tremors, lethargy, salivation, respiratory distress, etc. Cattle experience teratogenic signs such as arthrogryposis (crooked calf) or cleft palate.
- Collect urine or serum
A sheep presents to you for nasal discharge and face rubbing. You perform cytology on the copious discharge and note numerous eosinophils and mast cells. What is the most likely diagnosis?
Ostrus ovis infestation. Adult flies deposit larvae around the animals’ nostrils; the larvae then migrate up the nasal passages into the turbinates and sinuses. With time and multiplication of the larvae, hypersensitivity develops with the marked clinical signs of nasal discharge and face rubbing and shaking. Secondary bacterial infection can occur. The discharge usually contains numerous eosinophils and mast cells, which confirms the diagnosis in this case.
Further confirmation could be achieved with radiographs showing mineralized bots or with endoscopy, but this is not usually necessary. Enzootic nasal tumor could have similar clinical signs but tends to cause more dyspnea and would not have the eosinophils and mast cells seen in the discharge.
Tx: Ivermectin
What are the two main clinical syndromes of caprine arthritis encephalitis virus? What age goats are affected?
What happens to does that are affected?
How is this virus primarily transmitted?
How is this diagnosed? Treated? Prevented?
Kids 2-6 months old: Leukoencephalomyelitis; placing deficits in pelvic limbs, progress to tetraparesis
Goats 6 months and older: Polysynovitis-arthritis
Does affected may have some mammary gland involvement and develop a hard fibrous udder, which results in decreased milk production. Less commonly, goats may have an interstitial viral pneumonia.
CAEV is primarily transmitted to kids via milk or colostrum.
A. Ultrasonography of lungs
B. Agar gel immunodiffusion or ELISA - more specific
C. Necropsy (lungs heavy and don’t collapse)
D. PCR, virus isolation
NO tx
Serology 2x yearly; cull positive animals
Isolate kids, feed heat-treated colostrum, pasteurized milk
What is the cause of grass tetany in sheep?
Magnesium deficiency
Topic: Mycoplasma spp infection in goats
- What are the major clinical signs?
- What is seen on necropsy?
- How is it transmitted?
- pyrexia, swollen and painful joints, tachypnea, dyspnea, CNS signs
- Fibrinopurulen polyarthritis and interstitial penumonia
- Transitted to kids through milk or colostrum
Mycoplasma pneumonia, also referred to as enzootic pneumonia or atypical pneumonia, is caused primarily by Mycoplasma ovipneumoniae in sheep. It is usually spread from older animals to younger animals by the respiratory route (aerosol). Note that this route is in direct contrast to transmission in goats which have a different species of Mycoplasma (M. mycoides ssp mycoides) that is primarily spread in milk.
Changes in feed, lack of space, mixing of social groups, and elevated ammonia are all significant concerns with shipping sheep and goats by boat, which is frequently done in Australia. The mortality rates with boat transportation are higher than with other shipping methods.
What are the two most common causes of infectious keratoconjunctivitis in sheep? How is this treated?
Mycoplasma and Chlamydia
Treated with topical oxytetracycline ointment or powder. Those with bilateral corneal ulcers can get a long acting oxytet injection.
Enterotoxemia (overeating disease; pulpy kidney disease) is associated with high energy feeding of lambs on pasture or in a feedlot. The best preventive is ?
vaccination two times at 2 to 4 week intervals
What is the MOST significant cause of abortion in sheep in North America? Name some other common causes of abortion in sheep.
Campylobacter infection (or vibriosis) is the most significant cause of abortion in sheep in North America. C. jejuni is the most common and C. fetus is the other main cause of abortion.
Other common causes are Toxoplasma and Chlamydia psittaci. Bluetongue is much less common.
Brucella ovis rarely causes abortion in sheep although it does cause epididymitis. Sheep are not very susceptible to abortion from leptospirosis. Q fever, or Coxiella burnetii, is an uncommon cause of abortion and is more of concern due to zoonotic potential.
A farmer complains to you that many of his sheep have been doing poorly. You visit his flock and find many listless, emaciated adult sheep that are dyspneic and tachypneic. The sheep have normal temperatures, appetites, and no adventitious lung sounds. What is your top differential?
- List the category this organism falls under.
- Describe the clinical signs typically seen.
Ovine Progressive Pneumonia is caused by a lentivirus, also known as Maedi-Visna virus. This generally causes a chronic, progressive condition, and affected sheep tend to be afebrile and maintain their appetites as long as they do not develop secondary bacterial pneumonia.
This is in contrast to Pasteurella pneumonia, which tends to be much more acute. Clinical signs of Oestrus ovis tend to be more confined to the nares. Chlamydial pneumonia is rare in sheep.
You examine a sheep with thick brown-black crusts around the commissures of the mouth, in the oral cavity, and the feet, eyelids and teats. The sheep handler also has lesions on his fingers. What is the most likely cause of their lesions?
- List the category this organism falls under.
The correct answer is contagious ecthyma. These are the classic lesions for this condition, also known as orf or soremouth. It is caused by a parapoxvirus and is zoonotic.
Scrapie causes pruritus and secondary skin lesions, not the type of lesions and distribution described.
Vesicular stomatitis and FMD both primarily cause vesicular lesions.
Topic: Contagious echthyma (orf)
- What is the etiologic agent? This agent is related to?
- What are the clinical signs?
- How is it diagnosed?
- How is it treated?
- How is this disease prevented? What is important to remember about this prevention method?
- Is this disease zoonotic?
- This disease is more severe in what species?
- Parapoxvirus
- related to pseudocowpox and bovine papillary stomatitis virus - Usually young or newly introduced animals Lesions:
Painful papules
Vesicles/pustules
Crusts at mucocutaneous junction of lips - PCR or electron microscopy
- Typical course is 1-4 wks; Usually heals without scars
- Antibiotics - topical or parenteral for secondary infections - Isolate or cull affected animals, vaccinate the rest.
- Vaccination is effective during outbreak, but don’t vaccinate on orf-free farms because vaccine can cause disease - Zoonotic! Very contagious by direct contact with affected animals OR live vaccine - wear gloves
- More severe in goats than sheep, but less common in goats
Topic: Caseous Lymphadenitis
- Name the etiologic agent responsible for this disease.
- Gram + or -? - What are the clinical signs seen?
- How is this disease diagnosed?
- How is this condition treated?
- How can this be prevented?
- What is an important thing to remember about this disease?
- Corynebacterium pseudotuberculosis, a gram + facultative intracellular bacterium
- A. LN abscesses: submandibular, parotid, prescapular, prefemoral
B. Odorless, creamy - goats, caseous - sheep, purulent discharge
C. Weight loss, “poor doer” aka thin ewe syndrome - A. Culture abscess material
B. US, radiographs - aspirate any internal lesions - A. Culling is most practical
B. If valuable animal:
a. Isolate, drain + lavage with iodine
b. surgical excision
c. inject formalin into lesion (only if not going for human consumption)
d. AB in extra-label manner - either systemic or intralesional : penicillin, rifampin, tulathromycin - Recurrence is common even if treated!
A. Strict biosecurity
B. Don’t contaminate environment: collect purulent abscess material & lavage uid
C. Careful use of fomites (clippers & dipping tank solutions)
D. Vaccinate if endemic: reduces incidence, does NOT prevent
E. Fly control - This disease is zoonotic, highly contagious, and causes significant economic impact. It is also very environmentally resistant and can reside in organic debris for a long time.
Topic: Ketosis
1. The central process in ketosis revolves around?
2. Signalment
3. What is ketosis also known as in ewes and does? Explain why.
4. What other primary diseases may result in secondary ketosis?
5. Ketosis is characterized by an elevation in?
- Negative energy balance and inadequate feed intake.
Fats are consequently mobilized to support energy production but, in some instances, the body is unable to utilize all these fats (and/or their metabolites) thus resulting in excess production of ketone bodies.
- During times of negative energy balance the body is unable to produce enough OXALOACETATE to feed into the citric acid cycle. This results in mobilization of fat and subsequent production of ketones. - Ketosis occurs most commonly in lactating cows because the energy (glucose) necessary to support heavy milk production exceeds caloric and nutrient intake.
- Type 1 Ketosis - cow lactating 4-6 weeks with high production but not enough energy.
- Type 2 Ketosis - cow freshens and is overly conditioned (too fat)
3. Ketosis is also known as pregnancy toxemia in ewes and does; it occurs during the last 2-4 weeks of gestation when there is increased energy demands from rapidly growing fetuses (i.e. twins) combined with insufficient feed intake.
4. Displaced abomasum, metritis, peritonitis and mastitis, among others.
5. Acetoacetic acid, Acetone, B-hydroxybutyric acid
Topic: Ketosis Cont.
- What are the clinical signs of ketosis?
- How is ketosis diagnosed?
- Treatment?
- Frequent non-specific:
a. Depression.
b. Decreased appetite.
c. Weight loss.
d. Decreased rumen motility.
e. Decreased milk production.
f. The odor of ketones may also be detected on the breath of affected animals.
Pregnancy toxemia is characterized by non-specific signs of anorexia, weakness and depression - Based on history (recent parturition and heavy lactation).
● Elevated ketones in the blood, urine and/or milk.
● Decreased blood glucose.
● Liver enzymes may be elevated due to the central role that the liver plays in energy metabolism and gluconeogenesis - Correction of any primary disease that may be contributing to anorexia or inappetance should be initiated. Additionally:
- IV glucose
- Oral propylene glycol
- Corticosteroids (Dexamethasone. - used to prolong hyperglycemia because of their gluceoneogenic and appetite
stimulating effects)
- Tube feeding
- +/- insulin
Note: If treating pregnancy toxemia, induced parturition or cesarean section should be instituted along with IV and oral glucose supplementation.
● Clinical signs may spontaneously resolve without treatment if an equilibrium between milk production and dietary intake can be reached.
Topic: Ketosis
1. Prevention and control of ketosis
- Prevention and control of ketosis includes feeding and husbandry strategies during late lactation and the
dry period that aid in good body condition at calving.
Topic: Footrot
How does footrot in sheep differ from that in cattle?
The only difference is the etiology. In sheep, Dichelobacter nodosus is the main etiologic agent. Fusobacterium necrophorum can play a synergistic role. The treatment is the same!
Topic: Listeriosis
- List the risk factors of this disease.
- Describe the pathogenesis of this disease.
- What are the clinical signs?
- How is it diagnosed?
- How is it treated?
- What is the prognosis?
- Spoiled or wet feed, especially improperly fermented silage, rotten
vegetation/clippings, spoiled round bales, etc. More common in winter due to indoor feeding and wet conditions. - Ingestion of L. monocytogenes which can cross mucosal surfaces or invade
microabrasions. Travels up axons of cranial nerves into CNS causing micro-abscesses and focal encephalitis. - Unilateral cranial nerve signs such as facial nerve paralysis, pyrexia.
- no specific antemortem tests; look for unilateral cranial nerve signs
- NSAIDs, antimicrobials (oxytetracycline, penicillin), fluid support.
- fair if initiated early, otherwise poor.
Topic: Bluetongue
- What is the etiology of this disease?
- What are the clinical signs?
- How is this disease diagnosed?
- How is this disease treated?
- How is this prevented?
- There are at least 24 serotypes of the bluetongue virus (genus Orbivirus in the family Reoviridae)
- A. Cyanotic tongue
B. Serous to mucopurulent nasal discharge
C. Edema of lips, nose, face, submandibular area, eyelids, +/- ears
D. Infection of pregnant dams produces fetuses with hydrancephaly or
porencephaly causing ataxic and blind lamb - Viral isolation from blood of febrile animal, PCR to id specific isolate
- Encourage eating, NSAIDs, deep bedding
- Vaccinate in endemic regions, control vectors (culicoides)
Topic: Scrapie
- What is the signalment, etiology? Pathogenesis? Transmission?
- What are the c/s?
- How is it diagnosed?
- How is this treated?
- How is this prevented? Prognosis?
- Black faced sheep are genetically predisposed. Transmissible spongiform encephalopathy (TSE) caused by an abnormal prion protein,
related to bovine spongiform encephalopathy and chronic wasting disease of deer and elk. The protein is transmitted during lambing, not in utero, and incubates for 2-5 years. - Pruritus, progressive weight loss with good appetite, bunny hopping gait in pelvic limbs—> high stepping gait in thoracic limbs, death
- IHC = brain, 3rd eyelid or rectal mucosa
- rectal biopsy is easier and more sensitive - NONE
- USDA lab does IHC test on samples, traces back to herd, quarantines herd. Disease is fatal so prognosis is poor.
Topic: Coxiellosis
- Etiology & transmission
- C/S
- Treatment?
- Coxiella burnetti, an intracellular bacterium. Sheep, goat, and cattle are the most common reservoirs.
- C. burnetti is more heat resistant than Mycobacterium bovis (bovine TB) and can be found in unpasteurized milk.
- Set the standards for pasteurization temperatures.
- Spreads via inhalation, direct contact, or ingestion. - A. Ruminants: later term abortion, anorexia
B. Humans: Q fever (flu-like illness; abortion in pregnant woman) - NONE; an OIE notifiable disease.
