Many livestock owners will hear about a rabies report and think that it only applies to pet owners or that rabies cannot affect large animals, both untrue. Although not a common diagnosis, rabies can affect any mammal and should always be a differential for an animal showing neurologic signs. Since rabies is zoonotic and can be transmitted to people, it is  a serious worldwide public health concern, especially in developing countries where rabies can be extremely common.

The rabies virus is a fatal rhabdovirus that is transmitted in the saliva of an infected animal. It can be passed to other animals by a bite wound or when saliva gets into an open wound or on the animal’s mucus membranes. It can take several weeks for an animal to show signs after they are infected, but once they begin showing symptoms, they tend to die within a week. The rabies virus causes progressive encephalitis (a fatal brain infection). Livestock show signs like increased vocalizations, salivation, and behavior changes such as increased aggression or excitement. Occasionally, they will instead show paralysis signs and not want to get up. Other neurologic diseases in ruminants that may show similar signs and can be confused with rabies include tetanus, listeria, polio, botulism, scrapie, and lead poisoning. The only way to test for the rabies virus is to remove the infected animal’s brain and send it to the state diagnostic laboratory.

In South Dakota, rabies is most often found in wildlife such as skunks, bats, and raccoons. Coyotes and foxes can also carry it. Usually, when livestock or horses are infected with rabies, a single animal from a herd encounters rabid wildlife in a pasture and is bitten. Due to livestock being herbivores, it is typically very unlikely they would bite each other to transmit the virus further. According to the South Dakota Department of Public Health, from 2012-2021 there were 35 cattle, 3 horses, and 2 goats that tested positive for rabies after having brain tissue sent to the state lab. It is likely that a few cases go undiagnosed every year due to an inability or unwillingness to remove the brain of a potentially infected animal and have it tested.

Livestock that is potentially exposed to a rabid animal should be quarantined from other animals for six months and not sent to slaughter until eight months after potential exposure. To reduce the risk of having a rabies case on your farm or ranch, all cats, dogs, and horses should be regularly vaccinated for rabies. Some rabies vaccines are labeled for cattle and small ruminants, and the vaccine must be given yearly to them for continued protection. If you have valuable livestock or livestock that has frequent contact with humans such as a show animal or an animal that travels to petting zoos or other exhibits, it may be to your benefit and peace of mind to vaccinate them.