During the transition period, dairy cows experience increased energy demands due to calving and the onset of lactation, often resulting in negative energy balance (NEB). This condition promotes body fat mobilization and increases circulating non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHBA), potentially contributing to hepatic metabolic stress, systemic inflammation, and impaired mammary gland function. In addition, reduced hepatic responsiveness to growth hormone may decrease circulating insulin-like growth factor-1 (IGF-1), affecting metabolic regulation. Hepatic dysfunction and inflammatory responses may also alter albumin and globulin concentrations, resulting in changes in the albumin-to-globulin ratio (A/G ratio).This study aims to investigate the relationships among NEFA, BHBA, IGF-1, A/G ratio, hepatic function, mammary gland health, and lactation performance in transition dairy cows. Mammary gland health will be evaluated using the California Mastitis Test (CMT) and milk electrical conductivity, while milk yield and milking activity will be assessed using data from an automatic milking system (AMS). The findings are expected to clarify the potential value of A/G ratio as a supplementary.
- Cattaneo, L., Lopreiato, V., Piccioli-Cappelli, F., Trevisi, E., and Minuti, A. 2021. Plasma albumin-to-globulin ratio before dry-off as a possible index of inflammatory status and performance in the subsequent lactation in dairy cows. Journal of Dairy Science, 104(7), 8228–8242.
- McWilliams, C. J., Pereira, M. N., Duffield, T. F., Wood, K. M., and DeVries, T. J. 2024. Effect of glycerol supplementation in early lactation on metabolic health, milking activity, and production of dairy cows in automated milking system herds. Journal of Dairy Science, 107(11), 9360–9378.
- Meyer, I., Haese, E., Südekum, K.-H., Sauerwein, H., and Müller, U. 2024. The impact of automated, constant incomplete milking on energy balance, udder health, and subsequent performance in early lactation of dairy cows. Journal of Dairy Science, 107(1), 641–654.
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