A Review of Subclinical Ketosis in Dairy Cows: Epidemiology, Pathophysiology, Diagnosis, and Strategies for Prevention and Management

Subclinical ketosis (SCK) is a widespread metabolic disorder in high-producing dairy cows, commonly occurring during the transition period and early lactation. It arises from a negative energy balance and excessive mobilization of body fat, leading to elevated β-hydroxybutyrate (BHB) and non-esterified fatty acids (NEFA). Normally, cows meet their energy needs through gluconeogenesis and efficient metabolic regulation, but in SCK, this balance is disrupted, causing ketone accumulation and potential liver dysfunction. The prevalence of SCK ranges from ۱۰% to ۴۰% in Iran and globally, influenced by nutrition, genetics, and herd management practices (Asl et al., ۲۰۱۱; Sakha et al., ۲۰۰۷; Tehrani-Sharif et al., ۲۰۱۲). This disorder reduces milk yield, impairs fertility, and increases the risk of uterine and metabolic problems (Zhang et al., ۲۰۱۲; Samiei et al., ۲۰۱۰; Karimi et al., ۲۰۱۵). Early detection is possible through blood or milk BHB measurements and behavioral or metabolic sensors to identify at-risk cows before clinical signs emerge (Samiei et al., ۲۰۱۰; Tabrizi et al., ۲۰۰۷; Zakian et al., ۲۰۱۷). Prevention relies on maintaining energy balance via proper nutrition, ensuring adequate energy during the dry period, and supplementation with compounds such as propylene glycol, glycerol, monensin, and protected choline (Piantoni & Allen, ۲۰۱۵; Kupczyński et al., ۲۰۲۰). Propylene glycol is particularly effective in supplying glucose precursors, reducing BHB accumulation, and restoring energy balance. Successfully managing SCK requires an integrated approach combining precise nutrition, continuous metabolic and behavioral monitoring, and advanced diagnostics to safeguard health, improve milk production, and enhance farm profitability.

Keywords:

Subclinical ketosis , dairy cow , negative energy balance , propylene glycol , ketone