Remember when applying Nitrogen - pasture plants don't care where that Nitrogen comes from.
Recently I caught up with one of our clients. Their cows were producing at 1.3kg/Ms/day with milk ureas sitting around the early 30's. But they looked over the fence at the neighbour's grass and decided to apply chicken manure to boost their grass growth (working on the more grass must be better theory). I suggested they should be very observant and get ready to respond to their cows' reaction once they started to graze the N boosted pastures.
The phone rang "Our cows have crashed". "That's right, they were always going to" was my reply. (These cows were now producing significantly higher Urinary Nitrogen and the milk ureas had shot up to 42). "Feed them as much hay as they want to eat to get them back up to where they were" I suggested.
Several days later the cows had recovered production and the milk ureas were steadily falling.
The economics of the Nitrogen spiral go like this:
First you spend money on Nitrogen (in this case chicken manure). Then you have to spend some more money on energy - hay, maize or silage etc. to fix up the high protein diet, just to get your production levels to where they were before you added extra Nitrogen into your system.
These guys spent all that money to be no better off than they were in the first place. They now understand fully what was going on with their cows and have learnt a valuable lesson through experience (at a price).
There's nothing wrong with growing more grass but it must be of a nutritional value that your animals can convert into production – profitably.
Now my big question is: - What value do you place on soil testing and customized fertiliser programmes and full pasture testing for animal feed evaluation?
Prevention is always cheaper than cure.