Sudden Death

Why is it important to investigate causes of sudden death in cattle?

• May be start of disease outbreak

• May be preventable in other animals

• Possible zoonotic disease

• May be reportable disease

Potential causes of sudden death

• Lightening

• Bacterial infections

  • Cardiac histophilosis

  • Anthrax

• Toxicoses

  • Nitrate poisoning

  • Cyanide poisoning

  • Blue-green algae poisoning

Cause of cardiac histophilosis

Small gram-negative rod bacteria- Histophilus somni

Risk factors of Histophilus somni

Fall and winter

Pathogenesis of Histophilus somni

• Normal pharyngeal flora in some cattle

• Spreads via blood stream to different sites

• Damages heart through lesions

Histophilus somni transmission

• Aerosols

• Direct contact

Prevention and control of H. somni

• Highly prevalent bacteria, so eradication is not feasible

• Vaccine- usually part of multivalent

• Metaphylaxis

• Minimize stress

• Pre-conditioning

• Isolation and treatment of sick animals

Cause of anthrax

• Gram postitive boxcar-shaped rod- Anthracis bacillus

• Form endospores

• Produce exotoxins

• Zoonotic

Anthrax risk factors

• Dry locations

• Usually summers, wet springs then dry summers

Anthrax prevention

• Avoid grazing high-risk pastures (especially during dry summer/fall months)

• Vaccine- effective

• Minimize spore contamination

  • Deep burial of carcasses

  • Incineration of carcasses

  • Have vet investigate

Cause of blue-green algae poisoning

Cyanobacteria producing toxins (microcystins and anatoxins) and deplete oxygen in water

Cyanobacteria risk factors

• Warm temperatures

• Nutrient rich waters

• Agricultural run-of

• Human sewage run-off

• Climate warming

Cyanobacteria poisoning prevention

• Prevent access to waters with algal blooms

• Move water inlet pipes into deeper water

• Keep track of local BGA advisories via state agencies

• Submit water samples for testing

• Avoid nutrient run off into lakes

• Algicides (may kill BGA but promote release of toxins into water)

• Copper (could contribute to copper poisoning in sheep

Cause of nitrate poisoning

Sources of high nitrate (oats [hay])

Cause of cyanide poisoning

Many plants contain cyanogenetic glycosides- breakdown to release cyanide in rumen (arrow grass)