Can FT-Mid-Infrared Spectroscopy of Milk Samples Discriminate Different Dietary Regimens of Sheep Grazing With Restricted Access Time?

Abstract

Milk obtained from sheep grazing natural pastures and some forage crops may be worth a plus value as compared to milk obtained from stall-fed sheep, due to their apparently higher content of beneficial fatty acids (FAs). Fourier transformed mid-infrared (FT-MIR) analysis of FA can help distinguish milk from different areas and diverse feeding systems. The objective was to discriminate milk from sheep and milk from dairy sheep rotationally grazing Italian ryegrass or berseem clover for 2, 4, or 6 h/day. To test this hypothesis, a data-mining study was undertaken using a database of 1,230 individual milk spectra. Data were elaborated by principal component analysis (PCA) and analyzed by linear discriminant analysis (LDA) with or without the use of genetic algorithm (GA) as a variable selection tool with the primary aim to discriminate grazed forages (grass vs. legume), access time (2, 4, or 6 h/day), grazing day (first vs. last grazing day during the 7-day grazing period), and the milking time (morning vs. afternoon milking). The best-fitting discriminant models of FT-MIR spectra were able to correctly predict 100% of the samples differing for the pasture forage, 91.9% of the samples differing for grazing day, and 97.1% of the samples regarding their milking time. The access time (AT) to pasture was correctly predicted by the model in 60.3% of the samples, and the classification ability was improved to 77.0% when considering only the 2 and 6 h/day classes.

Use of Milk Infrared Spectral Data as Environmental Covariates in Genomic Prediction Models for Production Traits in Canadian Holstein

“…If, supposedly, some wavenumbers are associated with the presence of certain fatty acids in the milk, and it is the herd diet determining the presence of those fatty acids, the FTIR absorbance at those wavenumbers will contain information about the diet. In support of this hypothesis, FTIR spectral data have been used to successfully discriminate milk samples based on feeding or grazing systems [19,20]. The spectral wavelengths have also been shown to be in association with diseases incidence [21] and the cows' metabolic status [22], which suggest the strong relationship between the spectral data and the herd status, in general.…”

Investigation of phenotypic, genetic and genomic background of Milk spectra in Sarda dairy sheep

“…FTIR spectra can be used to identify which species produced the milk, thus avoiding adulteration of milk (Nicolaou et al, 2010;Pappas et al, 2008); moreover, milk spectra can be useful for discriminating the geographical origin of sheep milk (Caredda et al, 2017). Also, sheep milk spectra can be used to recognize dietary regimens or feeding systems (Molle et al, 2021). Hammami et al (2010) reported that sheep FTIR spectra of can be used to monitor milk quality during the lactation period, whereas Ledda et al (2023) predicted dry matter intake from FTIR spectra in lactating Sarda ewes.…”

“…FTIR spectra can be used to identify which species produced the milk, thus avoiding adulteration of milk (Nicolaou et al., 2010; Pappas et al., 2008); moreover, milk spectra can be useful for discriminating the geographical origin of sheep milk (Caredda et al., 2017). Also, sheep milk spectra can be used to recognize dietary regimens or feeding systems (Molle et al., 2021). Hammami et al.…”

Dairy Sheep Grazing Management and Pasture Botanical Composition Affect Milk Macro and Micro Components: A Methodological Approach to Assess the Main Managerial Factors at Farm Level

“…This implies that several concerns exist when implementing the authentication process for pasture-based feed in sheep dairy products [ 16 ]. Recent papers underlined, at the experimental level, that several tools could be implemented to increase the authentication methods of dairy products, such as milk alkanes and fatty acid profile detection [ 17 , 18 ]. In the dairy sheep farming system, data on the influence of permanent pasture on milk quality traits are scanty, in particular regarding carotenoids, colour and phenol contents as reported in a recent review [ 13 ], at both controlled conditions and at farm level.…”