We have had calves die from black leg. Really the only way you can tell is by cutting the skin over the brisket, between the front legs. If the muscle is red,pink and looks healthy then no it wasn't black leg. If the muscle looks purple/black and when you touch the brisket feels and sounds like bubble rap then yes the calf died of black leg. Just because you give the cow a shot does not mean the calf will be vaccinated to the disease. you have to give the individual a shot if you want it to be vaccinated against what ever disease. Black leg, as I was told, is mostly seen in fat cattle cases. It is very rarely seen in cattle two years and older. It can bee seen in cattle less than a year old, as stated by an earlier post. If you do have black leg, you can't get rid of it. Black leg is in the soil. So if the calf gets a cut, scrape, whatever, then lays on the ground in the dirt and gets dirt in the open surface then it could be infected with black leg.