One of the most common concerns I hear regarding working dogs on cattle is 'will it make them complacent & vulnerable when approached by a wild dog/dingo?'
In short, the answer is no. It can actually achieve the opposite, if its done right.
From my experience, there are four scenarios where predators can successfully prey on young cattle. Some we can influence, some are part of the natural cycle of life.
The first is when the calves are freshly born & left planted by the mother while she heads in for a drink until they are old enough to follow. Honestly, I don't really know how to counter this natural mothering technique, except maybe through grazing management so freshly calved mothers have easy & close access to feed & water.
The second is when an animal is weak or injured. Maybe the cow has bottle teats & the calf can't get a drink. Perhaps it was born with a deformity or issue that hasn't allowed it to thrive. Maybe it was mismothered during a muster & has been 'cooking for itself' for too long. Miss mothering can still happen, even when all the best care is taken to try to avoid it. These calves then become easy targets for predators who survive by hunting the weak & vulnerable. Its part of the cycle of life though we try to counter this as much as we can by hand raising what miss mothered calves we can find.
The third & fourth are occurances we can have more influence over with our dogs & help prepare our stock against. The majority of my experience is with brahman cattle who are notoriously curious, especially weaners (teenagers). They love nothing better than sniffing, licking, chewing, playing with everything new & interesting. Potential predators provide the same exciting new discovery, encouraging young stock to leave the sanctity of the herd to investigate further. All it takes is one well placed bite that even if the dog doesn't pull the weaner down immediately, can bleed, fester & weaken the calf with infection for a later meal. This is where educating stock to dogs can really have its advantage against predation. I would rather those weaners explore their curiosity with my working dogs, who won't seriously injure them but will teach them a predator is dangerous & to be respected with distance. Kind of like a kid learning the dangers of electricity by touching a mild electric fence rather than sticking a fork in a power socket.
They also learn at the same time to stay together as a mob, there is protection in numbers, not to spook & rush at any little sound, how to flow through yards & gateways, how to block up & walk when asked. How to handle stress & different situations they havent experienced before & this early education will stay with them through life & will be passed on to future generations who start learning it at their mother's side.
Which leads us to the fourth & I believe the most controversial scenario with working dogs, working cows with calves. This was something I had a hard time really knowing how to explain or even understand myself until I was able to spend some time with Spud Thomas who is an incredible wealth of knowledge when it comes to animal behaviour. We were out checking a mob of cows who were in the middle of a calf drop. As we moved around them, calves who had been out playing headed in to the safely of the main mob. Cows with young at foot slowly stood them up & walked in with their calf tucked in safe at their side. If calves ended up adrift of the herd, he allowed a couple of his working dogs to move up on them & gently shift them in the right direction until they realised where safety lay. He was teaching them how to protect themselves against predators, through the use of working dogs.
We've all seen the over protective cows who work themselves up into a fury, hurtling around in a frantic, well intentioned effort to protect their calf. And we usually praise them for being such good mothers. But these are actually the calves most likely to get taken by wild dogs. The cow knocks her calf over, stands on it as she tries to guard it or leaves it alone while trying to chase off the threat. This is exactly what the predators are hoping will happen, especially if they are working in a pack. The abandoned, bruised or injured calf is easy prey for a well coordinated pack. If that calf was able to stay tucked in next to mum while she stayed calm & close, those dog don't stand the same chance of an easy feed. We don't teach our cows that dogs aren't dangerous, but we take the fear & panic out of the situation by teaching them how to handle it.
The flow on benefits of having well educated stock are far reaching & often unrealised until you find yourself in the pressures of a new situation. And a good team of working dogs at your side is, for me, the best & most rewarding way to do it.