Evolution of NIR for forage analysis in Poland

By Prof. Zygmunt Maciej Kowalski, Department of Animal Nutrition and Feed Management , University of Agriculture in Krakow

Professor Zygmunt Maciej Kowalski explains how the use of NIR for forage analysis in Poland has evolved over the past 20 years, including the rise of NIR on-farm and the challenge of calibration development.

The Department of Animal Science and Feed Management has been using NIRS in the lab for feed analysis for many years. Mostly, we have been interested in forages, in their chemical composition and nutritive value. We started about 20 years ago using the old “filter device” but today we work with modern NIR equipment to perform the analysis of concentrates and forages for the field needs. We are also very much interested in creating calibrations for the above mentioned devices, based on our local feed sources. The main goal is to work on fresh material. We are also interested in calibrations used in the analysis of nontraditional feed resources, such as whole plant sorghum silage, wet beet pulp silage, DDGS etc.

With the cooperation of our business partners, our calibrations have been distributed to several labs in Poland.

The NIRS technique has become more and more accepted in Poland. A very important step was taken 4-5 years ago when the first portable NIRS instruments became available in the field. This was especially important for feeding advisers working with dairy herds. About 90% of the milk produced in Poland comes from small holders, from herds with less than 50 cows. These farms are too small to send their feed samples or TMRs to laboratories for chemical analysis. Based on positive experience with the portable NIRS, farmers started to believe in the results obtained by NIRS methods. Thus, a few feeding firms and even milk plants have bought the “stable” NIRS, providing regular service for a growing number of farmers.

Achieving the right dry feed/forage ratio for optimal nutritional value

Since becoming fans of the NIRS technique, we have been promoting this method of feed analysis among the farmers, especially from the dairy farms. The concept of analyzing fresh forages, which is possible now with the new generation of NIR, is very smart and useful in the field diet formulation. The speed at which results are now available is another major advantage. With conventional analysis it takes at least seven days, whereas with the NIRS it only takes 1-2 days. But the precision is similar.
A fast delivery of results helps a lot in correction of the diets, which may be very important for effective milk or meat production. Analysis of the chemical composition of the TMR (total mixed ration) allows fast and easy validation of the diet formulation.
Moreover, due to the lower price of NIRS compared to conventional methods, analysis of the chemical composition of feeds, has become more popular in our practice.

Key improvements in the past 10 years

There have been two main improvements over the last decade. The first one is the precision of the analysis which can be obtained using the newest NIRS instruments, due to new technologies in optics and software. Secondly, as an animal nutritionist working in the field, I greatly appreciate the possibility of analyzing the samples of fresh forages (silages, TMR). It eliminates the effect of drying and strongly reduces the effect of sample handling. Results can be obtained in the field, directly in front of a farmer, making it possible to analyze more forage samples within a given period of time. Moreover, today’s equipment is smaller, more compact and more mobile.

Calibration development

Not every NIRS user needs to be able to create his/her own calibrations. Often, such calibrations are of poor quality. The datasets for both calibration and validation are hard to achieve and the knowledge of the user may be limited.
From our experience, the development of the actual calibration is not the biggest problem. A much bigger challenge is getting a proper dataset, based on reliable wet chemistry analysis. We have been working on calibrations for many years and are proud that several of these have been implemented in practice.

We have experience working on methods already available in the software provided with the instrument. Mostly, using the PLS method, with the connection of the correction and transformation methods used for spectral data. Also, so called “local” methods, allowing integration of all our calibrations developed for fresh forages, look very promising.

As mentioned above there is still a lot of potential development work in feedstuffs analysis, including the determination of amino acids, fatty acids and vitamins, as well as the Maillard reaction products or mycotoxins. In my opinion the improvement in the precision of TMR analysis should also be considered here.

Future uses and potentials of NIR for forage analysis

Since the conditions of feed (forage) production are different in the various countries across Europe, the most important factor is to elaborate a universal system. I don’t think it is necessary to have separate calibrations for each country or region but it will be necessary to combine all the available calibrations and find a good selection system for a given sample.
I would like to see the NIRS instruments maintained in the feeding wagons used for cattle feeding. To do so we would need the calibrations for such conditions.
Since macronutrients are being replaced by micronutrients in animal nutrition (crude protein for amino acids; fat for fatty acids; vitamins etc.), my dream is an instrument that can detect such micronutrients with acceptable precision. The conventional methods of determination of micronutrients are very expensive and thus not realistic for practical use.

NIR has great potential and will be a driving force in the future of feedstuff analysis, at least for practical feeding. It is fast, less hazardous, equally precise as traditional methods, but much cheaper. It is quite possible that in the future it will replace the conventional methods of wet chemistry. In my imagination I see the farmer having his/her own small box which will control the chemical composition of forages or TMRs as it is currently done with the control of grain temperature and humidity.

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