Where has all the protein gone?

In this year of great uncertainty, even more so than previous years, and with the massive increase in costs of fertiliser and feeds (such as urea and nitrate), it is more important than ever for farmers to be furnished with the correct information to make informed choices.

For these reasons I would like to run through some recent on-farm findings comparing rolled barley treated with a urea-based preservative and crimped barley treated with human food preservative salts.

A farm in West Wales frequently combines barley for either crimping or rolling, and in some seasons both. Last year both crimped barley and rolled barley were made from the same field. The crimp was treated with CrimpSafe 300 and the rolled barley with Maxammon. In late January samples of both were taken and analysed for dry matter and crude protein using traditional chemical methods. When taking the samples, the farmer’s first notable comment was the higher yield of grain at crimping stage compared to rolling stage. However, we must not forget that many things change during grain maturation including the dry matter content. Fresh yield could be misleading.

Traditional chemical analyses of forage and feed components are often expressed on an ‘as received’ or ‘as fed’ basis not on a dry matter basis. What this means is that they are on a fresh basis, so for comparison purposes a conversion to dry matter basis is required.

The table below indicates the complete set of results as analysed and after calculation.

Looking at the protein on an ‘as received’ basis would indicate a higher protein content from rolled barley than crimped barley. However, when considering the DM content, the crude protein on a DM basis was 1.5% higher.

So where has all the protein gone?

As the crop matures there comes a point where field losses of dry matter and quality increase, thus a lot of protein is lost prior to harvest. In addition, previous research by myself and Dr Horst Auerbach has found that 40-70% of the urea nitrogen applied to the grain is lost to the environment through conversion to ammonia and then volatilisation from the store before it reaches the animal’s mouth. This last figure is unbelievable at first glance but if you have ever smelled urea-treated grains they do smell like a soaking wet baby’s nappy. That’s the ammonia disappearing up your nose and elsewhere, but not getting into the rumen where it could be useful.

All in all, I would be strongly advising farmers this year to make the most of any cereals they are growing for their stock and crimping them to keep the protein in the feed and reduce losses of both precious fertiliser and feed nitrogen. One of the other un-costed advantages of crimping is the land can be reworked and planted that little bit earlier making the next cropping cycle more efficient too.