Downer Cows: Causes and Factors

Downer Cows

• Cows that cannot rise are considered "downer" cows.
• Reasons for Downer cows include:
  • Foot lesions
  • Septic arthritis
  • Recent calving (obturator nerve paralysis)
  • Septic mastitis
  • Broken back/injury
  • Spinal abscess
• Downer cows are never slaughtered for human consumption due to the potential for disease.

Systemic and Non-systemic Factors contributing to Downer Cows

• Systemic Factors
  • Hypocalcemia
  • Hypophosphatemia
  • Hypokalemia
  • Hypomagnesemia
  • Toxic mastitis or metritis
  • Stress of parturition
• Non-systemic Factors
  • Calving paralysis
  • Fractures due to falls
  • Aortic thrombosis
  • Vertebral abscess
  • Vertebral fracture
  • Renal failure
  • DIC
  • Muscle ischemia & Tearing
  • Sciatic nerve damage
  • Hip luxation
  • Fracture of a femoral head

Other Important Points

• Cows cannot be slaughtered for meat during parturition.
• Signs of pain in cattle include:
  • Grunting
  • Grinding teeth
  • Dysphagia
• If a cow is missing an eye, suspect epithelioma (cancer eye).

Epithelioma (Cancer Eye)

• A malignant neoplastic growth affecting the eye and orbital region
• Most common cattle neoplasm found at slaughter
• Can result in condemnation of the carcass or reduced salvage value
• Seldom occurs before 4 years of age, peak incidence at 8 years old
• Has a hereditary basis, most common in Herefords.

Ante Mortem Inspection

• All species are inspected individually on the day of slaughter.
• Inspection includes:
  • At-Rest
  • In-motion
  • Poultry are exempt due to impracticality.

Important to Consider

• It's always recommended to take rectal temperature of animals pre-slaughter.
• This assists in determining wholesomeness, especially if abnormalities are found post-mortem.
• A higher than normal rectal temperature requires differentiation from true fever (disease).

Moribund Animals

• Livestock with a rectal temperature of 96°F or less are considered moribund (dying).
• Such animals should never be slaughtered for human food.

Epithelioma (Cancer Eye)

• Under federal meat inspection regulations, carcasses of animals affected with epithelioma of the eye or orbital region are condemned if:
  • It involves osseous structures of the head with extensive infection, suppuration, and necrosis.
  • There is metastasis from the eye or orbital region to lymph nodes, internal organs, muscles, skeleton, or other structures, regardless of the extent of the primary tumor.

Examination for Abnormalities

• Inspect for:
  • Injuries and fractures
  • Abnormal growths or swellings (actinomycosis, actinobacillosis)
  • Abnormal enlargements (hernias)
  • Abnormalities of skin, mucous membranes (signs of FMD, orf, injection sites)
  • Abnormal bodily discharges (nasal discharge, excessive salivation, diarrhea, pus)

Actinomycosis & Actinobacillosis

• Actinomycosis:
  • Affects bony tissue (lumpy jaw).
  • Causes a hard enlargement of the mandible.
  • Only the head is condemned.
• Actinobacillosis:
  • Affects soft tissue (wooden tongue).
  • Affects mandibular and retropharyngeal lymph nodes, and the soft tissues of the jaw and neck.
  • If the lung is involved, the entire carcass is condemned.

Injection Site Abscess

• An injection site abscess can be identified on ante-mortem inspection.

Bluetongue

• Bluetongue is a disease that can affect cattle.

Tuberculosis (TB)

• All tuberculin reactors are classified as "suspect" and require a special postmortem examination.
• Postmortem examination:
  • Inspect lymph nodes and organs for TB signs.
  • If lesions are found, tissues are sent to the National Veterinary Services Laboratories for confirmation.
  • If TB is confirmed, the carcass is condemned.
• Healthy Reactors:
  • No clinical signs on ante-mortem inspection.
  • No lesions on postmortem inspection.
  • Carcasses of healthy reactors are passed for cooking.

Conditions that Warrant Suspect Inspection (Ante-Mortem)

• TB reactors
• Minor epithelioma of the eye or orbital region.
• Signs of a Foreign Animal Disease

Important Points

• CNS diseases:

  • Examine for signs of rabies, listeriosis, and toxins.

• Lameness

  • Lameness requires further investigation.

• Depression or disinterest:

  • A sign of potential concerns.

• Downer Cows:

  • Never allowed in Federal facilities.
  • 10-15% of cattle affected with SCC that pass ante-mortem inspection are condemned post-mortem.

Scrapie

• Scrapie is a disease that can affect sheep.

Bovine Spongiform Encephalopathy (BSE)

• BSE can affect cattle.