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

Abstract

Fourier transform infrared spectral analysis is a cheap and fast method to predict milk composition. A not very well studied milk component is orotic acid. Orotic acid is an intermediate in the biosynthesis pathway of pyrimidine nucleotides and is an indicator for the metabolic cattle disorder deficiency of uridine monophosphate synthase. The function of orotic acid in milk and its effect on calf health, health of humans consuming milk or milk products, manufacturing properties of milk, and its potential as an indicator trait are largely unknown. The aims of this study were to determine if milk orotic acid can be predicted from infrared milk spectra and to perform a large-scale phenotypic and genetic analysis of infrared-predicted milk orotic acid. An infrared prediction model for orotic acid was built using a training population of 292 Danish Holstein and 299 Danish Jersey cows, and a validation population of 381 Danish Holstein cows. Milk orotic acid concentration was determined with nuclear magnetic resonance spectroscopy. For genetic analysis of infrared orotic acid, 3 study populations were used: 3,210 Danish Holstein cows, 3,360 Danish Jersey cows, and 1,349 Dutch Holstein Friesian cows. Using partial least square regression, a prediction model for orotic acid was built with 18 latent variables. The error of the prediction for the infrared model varied from 1.0 to 3.2 mg/L, and the accuracy varied from 0.68 to 0.86. Heritability of infrared orotic acid predicted with the standardized prediction model was 0.18 for Danish Holstein, 0.09 for Danish Jersey, and 0.37 for Dutch Holstein Friesian. We conclude that milk orotic acid can be predicted with moderate to good accuracy based on infrared milk spectra and that infrared-predicted orotic acid is heritable. The availability of a cheap and fast method to predict milk orotic acid opens up possibilities to study the largely unknown functions of milk orotic acid.

Estimation of genetic parameters for predicted nitrogen use efficiency and losses in early lactation of Holstein cows

“…Moreover, we should not forget that we studied here the proxies (PNUE and PNL) and not the underlying direct traits NUE and NL. The same situation (i.e., working on proxies based on imperfect predictions and not the direct traits) has appeared in many other studies (e.g., Zaalberg et al, 2020) that estimated approximate genetic correlation between the MIR predicted trait and other traits.…”

Genetic analysis on infrared-predicted milk minerals for Danish dairy cattle

“…The average RMSEP and R 2 were analyzed to determine the optimal number of latent variables. Once both the RMSEP and R 2 improved by ≤5%, the optimum number of latent variables was selected (Zaalberg et al, 2020). During the second step, we used the optimum number of latent variables from step 1, and performed an external validation to test the performance of the prediction model.…”

“…Increased spectral variability can increase prediction model accuracy (Davies, 2006;Soyeurt et al, 2009;Soyeurt et al, 2011;De Marchi et al, 2014). Spectral variability can be increased using multiple breeds to build the prediction model (Zaalberg et al, 2020;Soyeurt et al, 2011), or by using a method to select milk spectra that maximizes spectral variability (Soyeurt et al, 2009;Visentin et al, 2016).…”

“…These milk components can be predicted from infrared milk spectra with high precision, having prediction accuracies up to 1 (Luinge et al, 1993;Soyeurt et al, 2006). Infrared milk spectra have also been investigated for prediction of phenotypes such as concentration of milk fatty acids (Soyeurt et al, 2006;Eskildsen et al, 2014), concentration of BHB and acetone (Heuer et al, 2001;Van der Drift et al, 2012), energy status (McParland et al, 2011), methane emission (Dehareng et al, 2012), minerals (Soyeurt et al, 2009), milk metabolites (Zaalberg et al, 2020), and even genotypes (Rutten et al, 2011).…”

Importance of Bioactive Substances in Sheep’s Milk in Human Health

“…Accumulation of DNA damage is a well-known factor of aging and, therefore, is believed to be the main cause of Alzheimer’s disease [ 77 ]. Orotic acid is an important precursor in the biosynthetic pathway of pyrimidine nucleotides and, therefore, participates in the synthesis of DNA and RNA [ 78 ]. In mammals, it is released from mitochondrial dihydroorotate dehydrogenase (DHODH) by the enzyme cytoplasmic synthase UMP for conversion to UMP [ 79 ].…”