Aside from being a source of milk and cheese as well as all kinds of other dairy products on an indirect basis, the cow is known for contributing much in the way of being a dependable animal.
Dreaming of a dead cow means that you will be barren, financially speaking, for some time. Cows represent prosperity. They may not mean you're going to be a millionaire, but seeing a healthy cow in your dreams means you will do well in life. If you see an unhealthy or dying cow it means that you have a lot to worry about and are in danger. Don't let this happen to you. Make sure that you do all you can to prevent this from happening if you want to prosper in the future.
Since cows can also grow to become great companions to people, to dream of a dead cow may also symbolize the death of a strong friendship. In real life this most likely correlates to a strong human friendship but it can also apply to animals and pets too. This can be a traumatic time and the dream about the cow may make it worse, but just remember how much you cherish your friend.
If you have a dream in which you see a dead calf it means that you do not have good prospects for your future to grow and get better. You do not have a lot of different things that you can rely on anymore. A calf is meant to grow and provide later on in either milk or meat or cheese. If you have a dead calf it means that you cannot depend on it to grow and support you anymore as you were able to before. It is time for you to give up on the calf and it is time for you to let go. Unfortunately for you, you may not be able to recover from this.