Peripartum Ketone and its Relationship with Milk Quality in Dairy Cattle

Ketosis is a common metabolic disorder in dairy cows and has been associated with alterations in milk composition and a decrease in milk quality, impacting both the economic and nutritional value of dairy products. The purpose of this study was to evaluate ketone levels before and after calving and their effect on milk quality in cattle in the district of El Mantaro, Jauja in the Peruvian highlands. Multivariate analyses, including Principal Component Analysis (PCA) and clustering, were employed to explain the variability in the data better. The study was conducted at the Instituto de Investigaciones Tropicales y de Altura (IVITA) and El Mantaro experimental stations cattle in the district of El Mantaro, Jauja, using a total of 72 Brown Swiss cattle, all of which received similar management. Blood and milk samples were collected from all cows studied and analyzed in the laboratory for ketone levels and milk quality such as density, non-fat solids, protein, freezing point, solids, and lactose. The descriptive analysis revealed significant variations in the evaluated variables, highlighting a reduction in ketone levels after calving and consistency in milk composition, such as non-fat solids and density. The PCA showed that the first two principal components explained 49.8% of the total variability, dominated by compositional variables, while subsequent components contributed smaller proportions, reaching 100% with 11 components. The reduction in ketone levels after calving suggested metabolic stabilization associated with energy recovery during this stage, while differences in compositional variables such as protein and non-fat solids reflected the influence of factors such as diet, genetics, and physiological status. Although ketones showed weak to moderate correlations with the evaluated variables, the negative relationships with body condition and non-fat solids indicated that better nutritional and metabolic status might be associated with lower ketone levels.