Bovine Saliva can carry bacteria, and conversely, humans can pass pathogens to the calf's sensitive mouth.
Calves are born with a powerful, instinctive drive to suckle. In a natural setting, a calf would spend a significant portion of its day nursing from its mother. On modern farms, where calves are often separated from the cow and fed via buckets or bottles, this biological "itch" often goes un-scratched. calf sucking man on farm updated
While it might seem harmless to let a calf suck on your hand, there are several reasons why veteran farmers discourage the habit: Bovine Saliva can carry bacteria, and conversely, humans
Even after a calf has consumed its full meal of milk or milk replacer, the physiological urge to suck remains for about 20 minutes. If there isn't a teat available, they will seek out the next best thing: a gate, a fellow calf’s ear, or the person feeding them. On modern farms, where calves are often separated