cooking kale

That is odd.  How are you cooking it and what colour does it start out as.

Usually cutting veg or immersing in water are the main culprits for colour leaching.  You could try steaming, or cooking whole then putting a knife through it before serving.  Kale is also good if you stir-fry it.  You don't need a wok, just a roomy frying pan will do.  Heat a little oil, add sliced onion, plus garlic and chilli if you like it.  Once the onion is browned a bit, add sliced kale and stir in.  Add a small amount of liquid - water, stock, soy sauce - and slam a lid on to steam through 

steaming the Kale seems a good idea never thought of that one new shoot  going to pick some tomorrow and cook it fresh also stir-fry with onion and soy sauce sounds good my wife has already done stir-fry with red cabbage and red cabbage with apple

as for Kale and cattle I don't know of any farmer feeding kale to cattle or sheep round here mum i think giving my Emerald ice kale mite be a tad to extravagant for a stock feed