Thursday, July 21, 2016

 

Zuku

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Bovine questions make up 15% of the NAVLE® so it’s well worth spending some quality time learning the major diseases.


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This 4-part series on the top 20 bovine conditions will set you up for NAVLE® success.


 

5 of Zuku’s top 20 bovine conditions to know for NAVLE® success:

  1. Bovine lymphosarcoma

                    Submandibular lymphadenopathy

    • Classic case:
      • Central nervous system - paraplegia, tetraplegia, paraparesis, tetraparesis; head tilt, facial paralysis, dysphagia
      • Gastrointestinal system - free gas bloat, vagal indigestion, palpably enlarged abdominal lymph nodes, melena, thickened rectum
      • Lymph nodes - lymphadenopathy, exophthalmos, weight loss
      • Heart - unexpected and sudden collapse, death, congestive heart failure, jugular pulse, distended jugular or mammary veins, arrhythmia, tachycardia, weak pulse, subcutaneous edema
    • Dx:
      • Etiology: Bovine leukemia virus (BLV), an oncogenic retrovirus
      • Lymph node biopsy
      • Positive antibodies (AGID or ELISA) to BLV
      • PCR or antigen-capture ELISA for BLV
    • Rx: NO effective or legal treatment; D-penicillamine has been given to affected pregnant cattle to save a valuable calf but questionable
    • Pearls:
      • Grave prognosis
      • Affected cows will not pass slaughter inspection
      • Cows with BLV – most are asymptomatic, 5-10% get lymphosarcoma, and 30% have persistent lymphocytosis

  2. Ketosis
    • Classic case:
      • 3 types – thin cow up to 45 days post-partum (type I), obese cow peri-partum (type II), too much silage at any stage of lactation (silage type)
      • Dairy cow 1-4 weeks post-partum with mild anorexia, low milk production, malodorous breath
      • Pica or paresthesia, aggressive behavior
      • Mild proprioceptive deficits with hepatic failure
    • Dx:
      • Measure betahydroxybutyric acid in blood (best), milk, or urine; diagnostic is greater than 14.4 mg/dL in whole blood
      • Look for acetoacetic acid in urine with dipstick
      • Thorough dental examination
    • Rx: Depends on type:
      • Type I – simple and short term Rx: oral propylene glycol, IV dextrose, corticosteroids, oral potassium and calcium salts
      • Type II – difficult and longer-term Rx: transfaunate and force-feed, IV dextrose, oral potassium and calcium salts, insulin
      • Silage type – don’t feed silage with high concentrations of butyric acid to pre- and post-fresh cows!
    • Pearls:
      • Type I – excellent prognosis; prevent with low protein diet, maximize energy in early lactation, and monensin
      • Type II – poor prognosis; cull obese cows
      • Economically important because higher culling rates, more retained placentas & decreased pregnancy rates and milk production in obese cows

  3. Bovine viral diarrhea (BVD)
    • Classic case:
      • Unvaccinated younger cow with acute diarrhea, nasal discharge, ptyalism, ocular discharge, oral ulcers, fever, anorexia, coronitis
      • In-utero infection: early embryonic death, cerebellar hypoplasia, developmental defects, abortion
      • Persistent infection (PI): If a cow becomes infected by a NON-cytopathic strain of virus between 40-120 days gestation, or calf is from a PI dam, the calf will be PI and act as a reservoir; if infected by cytopathic strain later in life, cow gets mucosal disease
      • Mucosal disease: acute signs and fatal with 2-4 weeks
    • Dx:
      • Etiology: Bovine viral diarrhea virus, a Pestivirus
      • PCR on milk
      • Antigen-capture ELISA on blood or tissue
      • Virus isolation or histopath at necropsy
      • Ear notching for PI cattle: use PCR or ELISA
    • Rx:
      • None
      • Prevention: Test and remove PI calves; vaccinate
    • Pearls:
      • Grave prognosis except for subclinical disease in adult vaccinated cow
      • Worldwide, economically important pestivirus
      • Not zoonotic but very contagious

  4. Omphalitis, septicemia, joint ill, meningitis

                    Joint ill - septic metatarsophalangeal joint

    • Classic case:
      • Omphalitis – fever with swollen, painful umbilicus and patent urachus +/- GI pain with 2º peritonitis
      • Septicemia – calf less than 2 weeks old with fever, diarrhea, depression, systemic compromise
      • Joint ill – lameness with painful, swollen joint
      • Meningitis – opisthotonus, hyperesthesia
    • Dx:
      • Omphalitis – palpate and ultrasound umbilical structures
      • Joint ill – ultrasound/radiograph affected joint, aspirate and culture joint fluid
      • Meningitis – CSF aspirate shows increased WBC count and protein
    • Rx: Antibiotics and…
      • Omphalitis: Surgical removal for advanced cases
      • Joint ill: Lavage joint then instill antibiotics; analgesics/NSAIDs
      • Meningitis and septicemia: Systemic supportive care, NSAIDs, diazepam if seizures
      • Prevention: Make sure calves get a minimum 500 grams IgG on first feeding and 4 L colostrum by 2 hours of age; clean calving environment
    • Pearls:
      • Prognosis variable – good for omphalitis, poor for others (though some joints better than others)
      • Measure total protein at 24 hours’ age – adequate colostral transfer if greater than 5.5 g/dL

  5. Traumatic reticuloperitonitis
    • Classic case: Cow over 2 months of age with:
      • Acute anorexia and agalactia, unwillingness to move or lie down, arched back, fever, positive grunt test
      • +/- Papple shape (pear on right and apple on left) and scant feces if secondary vagal indigestion
    • Dx:
      • Positive withers grunt test – pinch withers while listening for a vocalization with stethoscope
      • Positive abdominal rebound test – percuss abdomen while looking for splinting and violent responses
      • Abdominocentesis – purulent or serosanguineous fluid
      • Cranial abdominal ultrasound or radiography
    • Rx: Similar outcomes with medical and surgical, better prognosis if treated early
      • Medical – magnet, laxatives, antibiotics, analgesics
      • Surgical – rumenotomy, antibiotics, magnet
      • Prevention: ONE magnet per cow given at 400-600 pounds weight prevents almost all cases!
    • Pearls:
      • 75% survival; bad outcome with secondary vagal indigestion, diffuse peritonitis, and pericardial involvement

owl    Zuku-certified bodacious websites:



Beef and dairy extension articles and links

Expansive compilation of informative articles and links.

Courtesy of Iowa State College of Veterinary Medicine.

Merck Vet Manual online

Can’t get enough of bovine NAVLE topics? Check out these key conditions:

Abdominal and urinary system problems: Hernias, (common!) patent urachus and hypospadias (NOT common).

Vagal indigestion, ruminal drinking (see images) and grain overload.

Neonatal diarrheas, especially colibacillosis and salmonellosis.


  The Cattle Site

Info on almost every cow condition.

Bovine Viral Diarrheal Virus fact sheet

An excellent overview.

Courtesy of the United States Animal and Plant Health Inspection Service.


Herd-level ketosis: diagnosis and risk factors

This website has lots of similar short overviews on bovine diseases.

Courtesy of the University of Wisconsin School of Vet Med.

Can’t get enough of bovine diseases?

1. Read more about calf scours here, courtesy of Colorado State University.

2. See a video of a DA surgery on a cow here.

 

bovine

Example of NAVLE®-format bovine question:

Which one of the following choices is the most common risk factor for bovine ketosis?

   A. History of abomasal displacement

   B. Thin body condition

   C. Early lactation

   D. Primiparous heifer

   E. High concentrate diet

Click here for the answer and explanatory text…

 

zukureview

 

Images courtesy of Dr. Lisle George and The Yorck Project (3000-year old image of a farmer plowing with cattle, Egypt)

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