A new mixed-grain calibration for rapid assessment of AME content that can help broiler producers get feed formulations just right, has recently been developed by Australian animal research consultant John L. Black and NIR spectroscopist Peter Flinn and their colleagues. Nirperformance talked to the developers about the calibration.
A mixed-grain versus single-grain calibration
Contrary to normal praxis when working with laboratory measurements, the new calibration combines several grain types in one calibration.
Animal performance and productivity is driven by the intake of metabolisable energy for which there is also a NIR calibration.The estimated digestible, metabolisable or net energy content of each ingredient is used in current feed formulation software to predict the combination of ingredients that will meet a specified energy content of the formulated diet.
|Peter Flinn explains: “It is much more difficult to obtain adequate sample numbers for a robust calibration when based on in vivo animal measurements, due to the time and cost”. Experience has shown that it is frequently more accurate to base an NIR calibration directly on in vivo values than on lab measurements which themselves can be poor predictors of important animal performance indicators. “Combining different cereal grain types in one calibration allows these problems to be at least partly overcome,” says Flinn.||The Calibration method
The calibration work is based on 293 grain samples and developed using modified PLS, as there were insufficient samples for either LOCAL or ANN methods.
For more in depth information about the calibration, read the white paper by R.J. Hughes et al. Separate Cereal Grain Calibrations for prediction of apparent metabolisable energy by Near Infrared Analysis
Flinn, Black and colleagues are also currently working on calibrations for rapid assessment of other feed quality aspects such as enzyme response (NSP/Phytase) and reactive or digestible lysine. With these calibrations, J.C Kim and J.C Spragg have developed NIR calibrations for the prediction of total and animal available lysine (and cysteine) in any sample of soybean or canola meal used in diets for pigs and poultry.