Genetic analysis of orotic acid predicted with Fourier transform infrared milk spectra

摘要

Fourier transform infrared spectral analysis is a cheapand fast method to predict milk composition. A notvery well studied milk component is orotic acid. Oroticacid is an intermediate in the biosynthesis pathwayof pyrimidine nucleotides and is an indicator for themetabolic cattle disorder deficiency of uridine monophosphatesynthase. The function of orotic acid in milkand its effect on calf health, health of humans consumingmilk or milk products, manufacturing properties ofmilk, and its potential as an indicator trait are largelyunknown. The aims of this study were to determine ifmilk orotic acid can be predicted from infrared milkspectra and to perform a large-scale phenotypic andgenetic analysis of infrared-predicted milk orotic acid.An infrared prediction model for orotic acid was builtusing a training population of 292 Danish Holstein and299 Danish Jersey cows, and a validation population of381 Danish Holstein cows. Milk orotic acid concentrationwas determined with nuclear magnetic resonancespectroscopy. For genetic analysis of infrared oroticacid, 3 study populations were used: 3,210 Danish Holsteincows, 3,360 Danish Jersey cows, and 1,349 DutchHolstein Friesian cows. Using partial least square regression,a prediction model for orotic acid was builtwith 18 latent variables. The error of the predictionfor the infrared model varied from 1.0 to 3.2 mg/L,and the accuracy varied from 0.68 to 0.86. Heritabilityof infrared orotic acid predicted with the standardizedprediction model was 0.18 for Danish Holstein, 0.09 forDanish Jersey, and 0.37 for Dutch Holstein Friesian.We conclude that milk orotic acid can be predictedwith moderate to good accuracy based on infrared milkspectra and that infrared-predicted orotic acid is heritable.The availability of a cheap and fast method topredict milk orotic acid opens up possibilities to studythe largely unknown functions of milk orotic acid.