Small Ruminant Respiratory Conditions Flashcards
What predisposes small ruminants to respiratory disease?
- poor ventilation (ammonia)
- dusty environments
- new animals in herd, comingling
- travel
What is the normal small ruminant adult respiratory rate? When does this typically increase?
10-30 bpm
- fever
- endotoxemia
- metabolic acidosis
- hypocalcemia
- pain
When are extended heads and necks most commonly seen in cases of respiratory disease?
- upper airway obstruction
- severe pulmonary disease
- pleuritis
What bot fly commonly infects small ruminants? How does it develop?
Oestrus ovis - inhabits the nasal passages of sheep > goat
- gravid females deposit larvae in and around the nostrils without landing
- clear-white larvae migrate into the nasal cavity
- when mature, the larvae leave the nasal passages, drop to the ground, burrow down, and pupate
- pupal period lasts 3-9 weeks, after which the fly emerges from the pupal case and pushes its way to the surface
What clinical signs are associated with nose bot myasis? What treatment is indicated?
- clear and mucoid discharge, can become mucopurulent and tinged with blood due to the hooks and spines of the larvae
- paroxysmal sneezing with migration of the larger larvae
- septic sinusitis if larvae are unable to get out and die within the sinus
Ivermectin
What causes caseous lymphadenitis?
Corynebacterium pseudotuberculosis - chronic. debilitating disease characterized by suppurative, necrotizing inflammation of 1 or more LNs
What are 4 predisposing factors associated with caseous lymphadenitis? What animals are most commonly affected?
- dirty conditions while shearing
- faulty shearing
- abrasions
- wounds from fighting or grass seeds
adult sheep and goats
What serves as a source of infection of caseous lymphadenitis?
discharges from ruptured abscessed superficial LNs + nasal/oral secretions from animals with pulmonary abscesses draining into the bronchial tree
- transmitted by direct contact with infective d/c or contaminated shearing equipment
What are the 2 forms of caseous lymphadenitis?
- SUPERFICIAL - palpable enlargement of one or more superficial LNs (submaxillary, prescapular, prefemoral, supramammary) –> commonly rupture with thick green to caseated pus with no odor as an onion-like structure
- VISCERAL - internal abscessation on organs –> chronic pneumonia, pyelonephritis, ataxia, fall in milk yields leading to poor growth and death of neonates
What are common postmortem lesions associated with caseous lymphadenitis?
- emaciation
- caseous abscesses filled with greenish-yellow pus in LNs
- characteristic laminated or onion-ring-like appearance with layers of caseous materials separated by fibrous bands
What history is indicative of caseous lymphadenitis?
suppurative lymphadenitis of superficial LNs, especially after shearing, docking, or castration
What samples are used for diagnosing caseous lymphadenitis? What 5 diagnostics are done?
pus, biopsy of LNs, blood, serum
- examination of pus smears with a Gram stain –> G+ polymorphic rods
- culture on blood agar for 1-2 days - pinpoint, off-white, faintly hemolytic
- detection of toxins by insulation of suspected materials
- detection of antitoxins by IHT, ELISA, CFT, or agglutination tests
- hematological and serum biochemical analysis
What treatments are recommended for suppurative lymphadenitis?
- antibiotics - Penicillin, OTC, PPG –> typically not enough by itself due to suppuration and cell wall lipids
- surgical evacuation of pus and washing with antiseptic
- surgical extraction of infected LNs
What are 4 ways that caseous lymphadenitis can be controlled?
- isolation and culling of infected sheep
- sanitary care during shearing, castration, or docking
- dip lambs and then adults to decrease chance of lamb infection
- vaccination - killed whole organism or toxoid - limits infection
What causes contagious caprine pleuropneumonia (CCPP)? How is it transmitted? What are the primary hosts?
Mycoplasma pneumonias
aerosol droplets
goats > sheep, wild ruminants
What clinical signs are associated with CCPP? What is seen postmortem?
- weakness, anorexia
- cough, tachypnea
- nasal discharge
- fever (104.5-106 F)
- KIDS = polyarthritis, respiratory disease, agalactia = typical triad in Mycoplasma outbreaks in goat herds
straw-colored pleural effusion and acute fibrinous pneumonia
What is necessary for proper control of CCPP? What treatment is indicated?
quarantine of affected flocks and strict biosecurity for introduction of new animals
Tylosin or long-acting OTC
What causes enzootic nasal adenocarcinoma? What clinical signs are seen?
retrovirus infects mucosal nasal glands in sheep and goats induces the development of tumors that obstruct nasal passages
- exophthalmos or skull deformation
- weight loss - airflow obstruction interferes with feeding
- most commonly seen in young animals with a hereditary predisposition
How is enzootic nasal adenocarcinoma diagnosed? What treatment is indicated?
- dorsoventral radiographs
- confirmed with histology and INH
- serologic tests are not available
euthanasia - protects the remainder of the flock, surgery not indicated due to virally-induced tumor expected to return
What are 4 common causes of aspiration pneumonia in small ruminants? How do these animals present?
- improper drenching - deposition of medications in lungs
- white muscle disease - deficient vit E/Se impair function of muscles of deglutition
- poor dipping technique with repeated immersion of patient’s head
- FB aspiration
separate from the group, pyrexic (104-105 F), arched back, reluctance to move, fetid smell to breath, mentally dull, dark red MM
How is aspiration pneumonia prevented? Treated?
- careful attention to use of appropriate techniques for naso/orogastric administrations of fluids/medications
- management of conditions that lead to prolonged weakness and recumbency
antibiotics + hydration + nutritional support + anti-inflammatories
What are 3 species of lungworms that affect sheep and goats?
- Dictyocaulus filaria
- Muellerius capillaris
- Protostrongylus rufescens
Lungworms:
Lungworm lifecycle:
How do lungworms cause disease? What signs are associated?
adults live in bronchi and cause alveolar/bronchial damage, resulting in blockage by exudates and collapsed lungs
- dyspnea
- cough
- intestinal irritation
- hypersensitivity
- loss of condition
- fever, toxemia
What postmortem lesions are seen in cases of lungworm infection in small ruminants?
- exudate in bronchioles and scattered patches of consolidation
- enlarged lungs due to edema and emphysema
- widespread areas of collapsed tissue with dark pink, hemorrhagic bronchitis
- fluid-filled air passages
- enlarged LNs
How are lunworm infections diagnosed? Treted?
Baermann + ELISA to detect antibodies
- broad-spectrum anthelmintics
- antimicrobials for secondary bacterial infections
- anti-inflammatories
How is lungworm infection controlled?
- vaccination with irradiated larvae
- reduce exposure
- regular deworming
- hygiene
What 2 disease processes does Pasteurellosis cause in ruminants?
- pneumonic pasteurellosis (shipping fever - cattle (6 months to 2 years) within 10 days of shipping, bronchopneumonia and pleuritis (Pasteurella multocida/hemolytica)
- summer pneumonia - Mannheimia hemolytica
(Pasteurella species are normal commensal organisms in the nasopharynx of cattle, sheep, and goats)
What are some predisposing factors to Pasteurellosis?
- viral infection - PI3, IBR
- Mycoplasmia infection
- Chlamydia infection
- transportation
- exposure to cold or hot weather, wet conditions
- overcrowding
- malnutrition, hunger, dehydration
- dipping
- trauma
What clinical signs are indicative of Pasteurella pneumonia?
- sudden onset of depression, lethargy, and inappetence
- separation from flock
- increased RR with abdominal effort
- fever (>105)
How is Pasteurella pneumonia diagnosed? What treatment is recommended?
transtracheal wash, bronchoalveolar lavage, gross necropsy
- antimicrobials
- ancillary anti-inflammatories, antihistamine, and bronchodilators
- mucolytics and expectorants
- vitamin E and selenium
- fluids
- metaphylaxis of high-risk populations
Pasteurellosis:
Pasteurellosis, postmortem:
How can Pasteurellosis be controlled?
- good husbandry and hygiene
- avoid overcrowding, draughty or unventilated housing, exposure to inclement weather
- avoid sudden changes in environmental conditions
- easily digestible and palatable food
- injections of vitamin C and A to increase immunity
- glucose + fluids
