Development in Indirect Infra-red Determination of Milk Acetone

Abstract

Milk acetone (AC) is an indicator of energy metabolism of cows and ketosis occurrence. AC result inerpretation is essential for prevention and treatment in dairy cow herds. There is necessary an effective method with reliable results. The goal was to evaluate the mid infrared method MIR–FT in terms of calibration for AC. Microdiffusion photometric (485 nm) method with salicylaldehyde as reference (RE) and MIR–FT (Lactoscope FT–IR, Delta (D); MilkoScan FT 6000 (F); Bentley (Bentley Instruments (B)) as indirect method were used. Selected (from high yielding dairy cows in early lactation) individual milk samples (MSs; n = 89) were used for MIR–FT calibration development and evaluation. Log AC correlation (r) between RE and indirect MIR–FT (D) was low (0.22, P < 0.05). The same parameter between RE and MIR–FT (F) was closer (0.589, P < 0.001; 0.632, P < 0.001 for n = 64. The artificial AC addition to milk samples had no visible effect on AC recovery by MIR–FT instruments. The AC values increased from 4.91 and 5.23 to 45.22 mg.l−1 by RE. There is no possibility to prepare the AC reference samples using artificial addition for MIR–FT calibration. In dependence on possible AC evaporation (a risk of AC result reduction) during storage conditions a knowlege about AC stability in sample is important. The similar AC results were obtained after milk sampling and after 48 hours of storage under cold conditions. This is new information for analytical work.

Keywords

• raw cow milk
• acetone
• ketosis
• photometry
• infrared spectroscopy
• calibration