Breed- and Parity-Associated Incidence and Manifestation of Metabolic Disorders in Holstein and Jersey Cows During the Postpartal Transition Period.

Dairy cows commonly experience negative energy balance during the periparturient period, predisposing them to metabolic disorders such as ketosis (KET), hypophosphatemia (HP), hypocalcemia (HC), and hypomagnesemia (HM). However, comparative data on breed- and parity-related differences remain limited. Therefore, these differences were evaluated in this study during the postpartal transition period. A total of 174 cows (149 Holstein, 25 Jersey) were monitored, and blood samples were collected from calving to 21 days postpartum at 3-day intervals to measure β-hydroxybutyrate, inorganic phosphorus, calcium, and magnesium concentrations. Metabolic disorders were defined using established thresholds. Data were analyzed using Fisher's exact test, the Mann-Whitney U test, and generalized estimating equations. HP was the most prevalent disorder in both breeds. Jerseys had 2.83 times higher odds of KET, whereas Holsteins had 4.98 times higher odds and an earlier onset of HM. Multiparous Holsteins showed higher incidences of HP, HC, and HM compared to primiparous ones, while parity effects were minimal in Jerseys. Breed and parity significantly influenced both the incidence and onset timing of postpartal metabolic disorders. These findings highlight the importance of breed- and parity-specific health management strategies in dairy cattle farms.