Why can vampire bats be harmful to livestock?

Vampire bats, which are the only mammals that feed exclusively on blood, can be harmful to livestock primarily because they act as vectors for disease. While the tiny incisions they make with their razor-sharp teeth are typically not serious on their own, they can lead to secondary infections. Most significantly, common vampire bats are considered pests because they frequently transmit rabies to cattle, pigs, and other livestock.1

Additionally, because these bats utilize a strong anticoagulant in their saliva to keep blood flowing while they feed, wounds may take longer to heal, further increasing the risk of infection or complications for the host animal.1