Finding out about crude protein

After a completely soggy winter, and a spring where the sun is only just getting around to shining, pasture growth levels got out of sync with calving and the start of the milking season.

Understandably, given what the ‘experts’ keep on telling them, many farmers rushed to put on urea to ‘kick-start’ growth. So, when the ryegrass perked up and started growing madly, those same farmers were unaware of the overdose of nitrates in it, and assured themselves that the enhanced ‘crude protein’ levels were just what their cows needed.

Strangely, or ‘as usual’, the cows not only got ‘squirty bums’ but the dreaded mastitis and frequent lameness problems were also back. Well that’s what happens in spring, isn’t it?

In 1959 a Frenchman, Andre Voison, published a book titled ‘Grass Productivity’ which looked in depth at grazing practices and also at ‘the so-called proteins of grass’. He cited research into the feeding of livestock, which had concluded that ‘the nitrogen in the grass has been analysed and multiplied by a factor close to six’ and that this multiplied figure was now being considered to correspond to the ‘crude protein’.

Organic combinations

In fact, as several respected scientists from the US (Albrecht), Britain (Synge) and New Zealand (Melville – then director of Grassland Research Station, Palmerston North) pointed out at the time, this figure represented an ‘ensemble of diverse organic combinations of nitrogen’. Later research has shown that most of it is in the form of nitrate, which in the rumen converts to ammonia at levels which cannot be handled by the rumen, and then gets into the bloodstream, then the kidneys and then gets excreted in urine.

This process causes problems for the cow and animal health starts to decline. Cows lose weight, get tired, are susceptible to mastitis and sore feet, and are much less likely to be ready to get pregnant again. More high empty rates.

On feedlots overseas they actually feed urea direct to cows, assuming that this will improve their protein intake. Here, we spread it on the pasture where what doesn’t get leached ends up in the grass, which our cows are eating, which already has high ‘crude protein’ (nitrate) levels in spring. And what doesn’t end up in cows goes off into the air as nitrous oxide and doesn’t do much for our somewhat imaginary climate change efforts.

Water quality problems

So, the warnings were out in 1959, long before we set up our own urea plant in the 80s.

Last week I was at a conference where the latest urea usage figures were being quoted at 800,000 tonnes, of which over 500,000 is being imported. And now we have enormous water quality problems from nitrate leaching, because most of it doesn’t get used by plants at all.

For a country claiming to be ‘100 per cent pure’ we seem to be doing an awful lot wrong to our pastures and dairy industry. Before the ‘urea fad’ took hold we grew more grass/ha using white clover to do all the nitrogen work.

As I wade through the knee-high clover on my little place, I know no urea has been seen here in 20 years, but bless the lime, mycorrhizae and bacteria which get added in my annual fertiliser spread. In my early days here I could not possibly have grown enough summer pasture to make hay and had to buy 24 bales and feed it sparingly.

Now I hope, despite climate change, that I can harvest another 53 conventional bales of hay from one acre of it again this year. I dished it out generously all winter and most of the spring. I had no long-lasting puddles and my small tribe of animals flourished.


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