doi:10.3390/dairy7010002 Text journal article Dairy 2025 © 2025 by the authors open access MDPI Harald Pothmann (Clinical Centre for Ruminants, Camelids and Herd Health Management, Clinical Department for Farm Animals and Food System Transformation, Departments, University of Veterinary Medicine Vienna) Michael Mitterer Florian Flicker Maryam Sahebi Vitezslav Havlicek (Centre of Biological Sciences, Department of Biological Sciences and Pathobiology, Departments, University of Veterinary Medicine Vienna) Urban Besenfelder (Centre of Biological Sciences, Department of Biological Sciences and Pathobiology, Departments, University of Veterinary Medicine Vienna) Alexander Tichy Marc Drillich (Clinical Centre for Ruminants, Camelids and Herd Health Management, Clinical Department for Farm Animals and Food System Transformation, Departments, University of Veterinary Medicine Vienna) Documento PDF Articolo scientifico http://creativecommons.org/licenses/by/4.0/ application/pdf Transition Period Beta-hydroxybutyrate Non-esterified Fatty Acids Acute Phase Proteins Subclinical Ketosis Immune Activation Evaluation of Hyperketonemia in the Transition Period of Dairy Simmental Cows and Association with Liver Activity, Uterine and Oviductal Health, and Reproductive Performance Hyperketonemia (HYK), defined by blood beta-hydroxybutyrate (BHB) ≥ 1.2 mmol/L, is described as a significant risk factor for cows developing postpartum (pp) diseases and impaired reproductive performance. The goal of the present study was to observe metabolic challenges in transition cows and to identify systemic markers reflecting HYK associated with lessened reproductivity. Fifty-four Simmental cows were monitored, revealing approximately 30% prevalence of HYK at the early pp period on 7, 14, or 28 days in milk (DIM). We assessed the dry matter intake, rumination time (RT), serum liver activity index, non-esterified fatty acids (NEFAs), acute phase proteins, and uterine and oviductal health. Elevated NEFA and reduced RT 14 days antepartum were a good predictor for HYK at 7 DIM. Hyperketonemia at 14 DIM resulted in higher milk yield compared with controls. We could neither detect differences in uterine health nor in reproductive key performance parameters between hyperketonemic and control cows, whereby the proportion of polymorphonuclear neutrophils in oviductal epithelia was significantly lower in hyperketonemic cows 14 DIM. We conclude that elevated concentrations of BHB in HYK 7, 14, or 28 DIM indicated energy supply to support physiological metabolic adaptations and lactation and that, in the absence of excessive inflammation during the transition period, HYK was not a risk factor for impaired fertility. Open Access Text Wissenschaftlicher Artikel eng https://phaidra.vetmeduni.ac.at/o:5401