The effect of grinding extent on near infrared spectrometry (NIRS) analysis of some animal feeds

A study was performed aimed at evaluating the method of sample grinding and its effect on the results of the analysis using the method of near infrared spectrometry. The object of the analysis was feed materials commonly used in animal feed manufacturing, such as cereal grain, wheat bran and high-protein materials (soybean meal). We also tested feed mixtures for poultry and pigs. Laboratory samples were ground on three milling devices – with the sieve of 1.0 mm or 0.5 mm, and a disc mill with minimum working aperture. The content of nutrients was analyzed with the help of the InfraXact spectrophotometer scanning within the range of 770–2,500 nm. The analyses revealed that within the range applied the method is resistant to the diversified granulometric composition of the samples. However, excessive grinding of the research material should be avoided (a sieve of 0.5 mm) during analyzing water, due to potential overheating of the sample which could lead to partial evaporation of the component.