Kamma is the Pali word for action. In Sanskrit it is Karma. The full phase you are speaking about is kammavipaka, or the fruition of action. Action = cause⇢effect. Once the killing is done, there is no more cow, no more animal to speak of it is just flesh. Eating it doesn't carry the same consequence, if any. I'm not sure (well, maybe dietary consequences). Monastics may not request meat or eat food they suspect contains flesh of an animal killed for them. They can't see or hear or
suspect an animal was killed for them. They can't dig in the dirt, pick fruit, cut fruit with seeds, uproot a plant, and they must filter their water and return any living being found to the source. Raw meat can't be cooked in monastery kitchens or stored on monastery grounds. While some Buddhist schools are vegetarian or vegan, the Buddha never forbid the eating of meat, except within those guidelines for monastics and with the first precept for laypeople. - this could get a lot longer but I already lost my first draft that I was writing on my phone

. it is very complex and I don't pretend to know more than what is helpful for me at this point.
I also believe that there is a point where one can understand an animal is clearly suffering and has little hope of recovery. I don't think that at that point to take the life of that animal would carry the same negative karmic effect because the intention is to relieve the suffering. Intention is the driver behind action/kamma. I don't let my animals suffer.
We are speaking of worldviews here and it is impossible to explain a worldview in a post, especially before coffee

(if ever). If one can peek outside their own worldview for a while to try to understand the views of others, we would have far less discord in our world. I also appreciate we can exchange very different ideas in the spirit of communication.