Propylene glycol (PG) is the cornerstone of both prevention and treatment of ketosis in fresh dairy cows, with differentiated protocols based on clinical status and timing of intervention.
For prevention, PG is administered at 4–8 fluid ounces (approximately 120–240 mL) per head daily as a drench or feed additive, beginning two weeks before freshening and continuing for six weeks after calving.FDA DailyMed An… Monensin, available as a sustained-release bolus (Kexxtone), reduces the incidence of ketosis by over 50% and increases milk yield in the first weeks after calving, though its antibiotic nature and cost limit universal application.Veterinary Scie… Body condition management during the dry period is fundamental — avoiding excessive subcutaneous fat and abdominal adiposity at parturition reduces the degree of negative energy balance and lipolysis that drives ketone body accumulation.Veterinary Medi…
For treatment of subclinical ketosis (SCK), PG is administered at 400 g/head/day, and treatment initiated within the first 7 days of lactation achieves a cure rate of 76.5% — substantially higher than treatment begun later in lactation.Frontiers in Ve… The SCK prevalence in the first 9 days of lactation reaches 41.5% in some herds, making early screening essential to capture the window of highest treatment efficacy.Frontiers in Ve… PG treatment also improves milk quality parameters and increases milk yield, supporting its economic justification.Frontiers in Ve…
For treatment of clinical ketosis (type I), intravenous glucose combined with oral PG is the recommended protocol; glucocorticoids are avoided in type I ketosis.Veterinary Scie… The treatment course for clinical disease is PG at 4–16 fluid ounces (approximately 120–480 mL) per head per day for 10 days as a drench.FDA DailyMed An… In cows with concurrent fatty liver or abnormal liver function — indicated by serum aspartate aminotransferase (AST) activity above 100 IU/L — standard glucose and PG alone are insufficient, as secondary ketosis with hepatic involvement is difficult to resolve with gluconeogenic precursors alone.Journal of Vete…
Diagnosis thresholds that trigger treatment are blood beta-hydroxybutyrate (BHB) ≥ 1.2 mmol/L for SCK and ≥ 3.0 mmol/L for clinical ketosis, with blood BHB confirmed as the gold standard at sensitivity and specificity above 90%.Veterinary Scie…+4 The fat-to-protein ratio in milk greater than 1.4 and non-esterified fatty acids (NEFA) greater than 0.4 mmol/L serve as useful screening tools, though both carry lower diagnostic value than direct blood BHB and are influenced by lactation stage and diet.Veterinary Scie… Milk BHB by Fourier Transform Infrared Spectroscopy is a validated herd-level screening method.Frontiers in Ve…
Prolonged PG use carries the risk of reduced appetite, which must be monitored during extended preventive protocols.Veterinary Scie… Cows with SCK that are not identified and treated face increased risk of displaced abomasum, metritis, lameness, and reduced reproductive performance, with per-case economic losses estimated at $203 (Canada) and $289 (United States).Journal of Dair…+1
| Intervention | Dose / Protocol | Efficacy | Key Caveat |
|---|---|---|---|
| PG — prevention | 4–8 fl oz/head/day, 2 wk pre-calving through 6 wk post-calving | Reduces ketosis incidence | Prolonged use may reduce appetite Veterinary Scie…+1 |
| PG — SCK treatment | 400 g/head/day | 76.5% cure rate when started within first 7 days of lactation Frontiers in Ve… | Efficacy declines after day 7 Frontiers in Ve… |
| PG — clinical treatment | 4–16 fl oz/head/day × 10 days as drench | Standard of care for type I clinical ketosis Veterinary Scie…+1 | Insufficient alone when fatty liver/AST >100 IU/L present Journal of Vete… |
| IV glucose | Combined with PG for clinical ketosis | First-line for type I clinical ketosis Veterinary Scie… | Glucocorticoids contraindicated in type I Veterinary Scie… |
| Monensin (Kexxtone bolus) | Sustained-release bolus | Reduces ketosis incidence by >50%; increases early-lactation milk yield Veterinary Scie… | Antibiotic; requires veterinary supervision; high cost Veterinary Scie… |
Would you like guidance on herd-level screening protocols — specifically the optimal timing and frequency of postpartum BHB testing to maximize detection within that high-efficacy treatment window?