Fig. 2

Predicted against observed measurements (a) and residual against predicted measurements (b) applying the milk Fourier transform mid-infrared spectrometry partial least square (PLS) regression model M3 predicting heat production (HP) of dairy cattle in respiration chamber. Prediction model M3 was computed by weighted averaging the morning and afternoon milk spectral data, in which each morning or afternoon absorption spectra was multiplied to the respective milk yield and subsequently the average spectrum was computed