Hi Danl! I'm quite envious of your manure find. You will probably want to let the manure sit for awhile- it needs to cure. If you spread it while its fresh the nitrogen content might be too high.
If I was lucky enough to get a tonne of cow poo I would compost it- with shredded leaves, newspaper, sawdust, (try and get some carbon added to the mix) and all the other lovely things that go in compost. This way you may have to wait longer- but you will have amazing compost at the end!
And seeing as it's such a big pile of manure- if you can get a big pile of carbon/dry ingredients to mix in, it may not take so long for it to be ready.
The link I'm giving you is not directly related to cow manure, it is actually my blog about gardening- if you have time to peruse feel free to, if not than I hope my info helped :) Best wishes!

Here is a link that might be useful: Shameless link to my blog