Salmonellosis is an infection of the digestive tract by the bacterium, Salmonella enterica. Salmonella is widespread and can be found on many dairy farms and in many species of animals, including mammals, birds, insects, reptiles and humans. This bacterium usually infects an animal when its immune system is suppressed or when it is exposed to high doses of the organism.
Both clinical outbreaks and subclinical infections of Salmonella can drain profit from the dairy operation. Salmonella infection in a dairy herd can lead to losses from:
milk production decline
death in any age group of livestock
losses from antibiotic contaminated milk
increased cost due to delayed culling while antibiotic residues clear
increased labor for management of sick animals
reduced feed efficiency the inability to sell animals originating from an “infected” herd
Salmonella infection is also a significant public health risk to farm families, employees and visitors. Outbreaks of this disease often occur after episodes of flooding or runoff, when cattle feed or equipment is contaminated with flood waters carrying the organism.
Salmonella is a highly contagious bacteria that spreads primarily when animals consume contaminated feed or water. Cows, birds and rodents shed large numbers of Salmonella during the clinical stage of disease and readily contaminate their surroundings, including feed, water troughs, barnyards, feeding equipment and people who work around them. Most of the bacteria are shed in the feces, but when systemic illness develops, the organism is also shed in saliva, nasal secretions, urine, and milk.
Some animals, upon recovery, become carriers and continue to shed organisms for many months. They may show no more outward signs of the disease but are a continuing source of Salmonella contamination.
Salmonellosis is often seen as an acute disease, usually starting with a high fever (103-106 degrees), that progresses to serious diarrhea, which often contains blood and is foul smelling. The affected animal becomes dehydrated and depressed, and may die. Your veterinarian should become involved as soon as this disease is suspected.
Treatment of salmonellosis with antibiotics is seldom effective by itself, especially if the disease has progressed to the diarrheal stage. The most effective treatment of the sick cow is primarily by supportive therapy, such as oral or IV electrolytes and fluids.