Top 20 Bovine Conditions Pt. 1

Bovine lymphosarcoma

Only approx. 5% of BLV-infected animals get lymphosarcoma

• 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: 25% of cases have peripheral lymphadenopathy; can also see exophthalmos, weight loss
  • Cardiac: 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
  • Gold standard: lymph node biopsy and histopathology confirms lymphosarcoma
  • BLV infection: Positive antibodies ( ELISA most common) to BLV or PCR or antigen-capture ELISA
  • Note: Serologic or virologic positive for BLV does not definitely diagnose lymphosarcoma because prevalence of BLV is high and so few seropositive cases develop lymphosarcoma
• Tx: NO effective or legal treatment
  • Control: test and cull positive animals greater than 6 months of age in herds with a low BLV prevalence
  • Prevent horizontal spread in herds with high prevalence by changing needles, using rectal sleeves, and good fly prevention
• Pearls:
  • Grave prognosis for lymphosarcoma
  • Cows w/ lymphosarcoma will not pass slaughter inspection
  • Prevalence of BLV in most U.S dairy herds is high, but most are asymptomatic and their prognosis for life is good
  • Upwards of 30% of infected animals will have persistent lymphocytosis serving as a reservoir for further spread

Ketosis

• Classic case:
  • 3 types – thin cow up to 45 days post-partum (type I), obese cow peri-partum (type II), or 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
  • Subclinical
    • Can be common in dairy herds
    • High blood ketone levels without obvious clinical signs
    • Decreased milk production and reproductive fertility possible
    • Increased risk of metritis, displaced abomasum, early culling from the herd
• Dx:
  • Measure betahydroxybutyric acid in blood (best), milk, or urine; w/ clinical ketosis is greater than 14.4 mg/dL in whole blood
  • Look for acetoacetic acid in urine with dipstick
• Tx: Depends on type:
  • Type I – simple and short term Tx: oral propylene glycol, IV dextrose
    • Corticosteroid use is controversial
    • Drives glucose into cells but also quells the immune response
    • Risky in a post-partum animal
  • Type II – difficult and longer-term Tx: transfaunate and pump with liquid nutrition via ororuminal tube, IV dextrose
  • 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; manage dry periods and dry cow nutrition to prevent obese cows, cull
  • Economically important because higher culling rates, more retained placentas, decreased pregnancy rates, and decreased milk production in obese cows

Bovine viral diarrhea (BVD)

• Classic case:
  • Unvaccinated younger cow with acute diarrhea, nasal discharge, ptyalism, ocular discharge, oral ulcers, fever, anorexia, coronitis (not all will occur)
  • 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
  • Gold standard: virus isolation however PCR on milk, serum, whole blood, tissues or semen is the rapid test of choice
  • Antigen-capture ELISA on blood or tissue
  • Often requires paired serology to definitively diagnose recent infection vs. exposure or vaccination
  • Virus isolation or histopath at necropsy
  • Ear notching for PI cattle (PCR or ELISA): most commonly done on calves
• Tx:
  • Supportive care for simple adult, unvaccinated cows showing signs of diarrhea, fever and anorexia; prognosis for these animals is good
  • None for calves born with developmental defects or animals with mucosal disease
  • Prevention: Test and remove PI calves; vaccinate
• Pearls:
  • Grave prognosis except for adult with mild, non-mucosal disease
  • Worldwide, economically important pestivirus
  • Not zoonotic but very contagious

Omphalitis, septicemia, joint ill, meningitis

• Classic case:
  • Omphalitis: fever with swollen, painful umbilicus and patent urachus +/- GI pain with secondary peritonitis
  • Septicemia: calf less than 2 weeks old with fever, diarrhea, depression, systemic compromise
  • Joint ill: lameness with painful, swollen, hot 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
• Tx: antimicrobials 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 and 4 L colostrum by 4 hours of age; clean calving environment
• Pearls:
  • Prognosis variable: good for omphalitis, poor for others
  • Measure total protein at 24 hours’ age: adequate colostral transfer if greater than 5.5 g/dL

Traumatic reticuloperitonitis

• Classic case:
  • 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
  • Sloshing fluid sound left thoracic cavity in severe cases with pericarditis
  • Rare in pre-ruminating heifers
• Dx:
  • Positive withers grunt test: pinch withers while listening for a vocalization with stethoscope
  • Look for pain response while balloting left ventral abdomen
  • Abdominocentesis: purulent or serosanguineous fluid
  • Cranial abdominal ultrasound or radiography
• Tx: Similar outcomes with medical and surgical, better prognosis if treated early
  • Medical: magnet, laxatives, antimicrobials, analgesics
  • Surgical: rumenotomy, antimicrobials, magnet
  • Prevention: ONE magnet per cow given at 400-600 pounds weight can prevent
• Pearls:
  • 75% survival; bad outcome with secondary vagal indigestion, diffuse peritonitis, and pericardial involvement