Scientific Reports
Saba Behdad, Reza Massudi, Abbas Pakdel & Sahereh Joezy Shekalgorabi, 2025, Milk NIR spectroscopy and Aquaphotomics novel diagnostic approach to Paratuberculosis in dairy cattle, Scientific Reports, 15:19239, https://doi.org/10.1038/s41598-025-99421-x
Mycobacterium Avium subspecies Paratuberculosis (MAP) causes Johne’s disease or Paratuberculosis,
a chronic, progressive intestinal disease in ruminants. The incidence and prevalence of Johne’s disease
are higher in dairy cattle herds because of intensive breeding and high production. Developing non-
destructive diagnostic methods for early detection of this disease by simple sampling is paramount
for breeding, economic, and health programs. Conventional methods are almost entirely destructive,
have low accuracy, and are time-consuming. Near- infrared spectroscopy (NIRS) and Aquaphotomics
can detect changes in biofluids and thus have the potential to diagnose the disease. This study aimed
to investigate the diagnostic ability of NIRS and Aquaphotomics for Paratuberculosis in dairy cattle
by milk sample. Milk samples from dairy cattle were collected in the NIR range (1300–1600 nm) 60
days before and 100–200 days after calving in two groups, positive and negative, using the three
same consecutive ELISA test results of blood plasma and milk, as a reference test. The NIRS and
Aquaphotomics methods in quadratic discriminant analysis (QDA) and support vector machine (SVM)
models achieved high accuracy in detecting negative and positive groups. In internal validation,
SVM and QDA models in 12 water absorbance bands had 100% accuracy. In external validation,
milk samples with blood plasma ELISA reference test achieved 100% sensitivity, which is more
accurate than milk ELISA as a reference test. The current study found that monitoring milk with NIR
spectra provides an opportunity to analyze antibody levels indirectly via changes in water spectral
patterns caused by complex physiological changes, such as the amount of antibodies related to
Paratuberculosis by aquagram.
