Herd and Flock Health

There are several basic considerations required after a flood to ensure the health of animals. Do not wait to report any signs and symptoms in your animals. Diarrhea, pneumonia, blood in urine, high fever or off-feed all herald the approach of what could be serious diseases. It will be several months before drying and sunlight can render environmental contamination harmless.

Don't forget your own safety. During cleanup, should an injury (even cuts and scrapes) occur, tetanus immunization should be sought.


Beware of mould growth in damp grain and hay. Toxins produced by moulds can harm animals.

Do not use feed contaminated by rodents. All rodents are potential disease carriers.

Disease Potential

Sudden illness or death losses should be reported at once to veterinarians or provincial government authorities.

All cuts and scratches should be treated preventively, because of the danger of tetanus.

  • Floodwaters transport some soil-borne disease-causing organisms including:
    • blackleg
    • erysipelas
    • fungal diseases
    • leptospirosis
  • There is also danger from other diseases such as:
    • tularemia (from rodents)
    • salmonellosis (from flooded sewage lagoons or garbage dumps)
    • tetanus (from soil)
    • anthrax (from soil)
    • foot-rot (Soft pastures and wet drinking areas pose a threat to cattle. The judicious use of copper sulphate in certain areas may be warranted. Treat animals with antibiotics as soon as the disease occurs.)

Drugs and Medications

Discard all pharmaceuticals and medicaments exposed to floodwater or left unrefrigerated for any period of time. If in doubt, check with your veterinarian.

Follow label directions and withdrawal times when using antibiotics.  Use them only where they are really needed. There should be evidence of disease condition that requires treatment.

Animals being returned to previously flooded pastures are at risk to clostridial disease such as blackleg. All cattle (calves and adults) should receive a vaccination for clostridial disease (preferably the 8-way type).

All swine should be vaccinated against erysipelas.

Usually no other medications are required, unless special circumstances occur; a veterinarian should then be consulted for advice.


Rodent control should be carried out if possible, in order to minimize the chance of spread of disease organisms carried by rats and mice.

Stress on Animals

Stress from transportation back to the farm or to pasture cannot be prevented. Acclimatization on new pasture will take several days. Use good common sense when handling animals instead of trying to counteract stress with medications. Feeding animals poor-quality or mouldy feeds may compound the animal stress.

Tranquillizers may be beneficial in a few specialized cases, but the value of widespread use is questionable.

Production may drop in dairy cows and could remain somewhat depressed for the rest of the lactation. Transportation will cause setbacks in gains in beef and swine feeder animals. Little can be done to counteract this.

All animals should be given adequate amounts of vitamins and minerals, which help to counter the effects of stress.

Be careful when moving animals to pastures that have come through the winter in poor condition. Moving animals in poor condition may provide enough stress to allow them to go down.  Move them only if they are in reasonably strong condition.


For further information, or if you suspect any animal health concerns, please contact the Chief Veterinary Office or call 204-945-7663 in Winnipeg