In early lactation when milk production outpaces nutrient intake, cows go through a period of energy deficit. Approximately 40% of cows don’t adapt to this period appropriately and develop excess ketone bodies, which results in ketosis. Also called hyperketonemia, this disorder carries an estimated total cost of $289 per case.
New research from Cornell University (Capel et al., 2021) investigated the efficacy of 3 different treatment protocols for ketosis commonly used on farms. The trial was conducted on 4 New York dairy farms using 1,249 cows with no previous history of ketosis, retained placenta or metritis. Cows between 3 and 16 days in milk were screened weekly for ketosis, defined by blood β-hydroxybutyrate (BHB) of ≥1.2 mmol/L. Cows identified as positive for ketosis were assigned to 1 of 3 treatment groups: (1) 300 mL of oral 100% propylene glycol daily for 3 days; (2) oral propylene glycol plus 500mL of 50% dextrose delivered intravenously on the first day of treatment; or (3) oral propylene glycol plus 500 mL of 50% dextrose delivered intravenously for 3 days. Each treatment’s effect on the resolution of ketosis, risk of adverse health events during the first 60 days in milk and milk yield in early lactation was evaluated.
The incidence of ketosis in the 4 study herds ranged from 20.3% to 47.6%. Overall ketosis incidence for all cows screened in the study was 30.1%. (As a comparison, research by Duffield, 2000; and McArt et al., 2012a identified an average incidence of ketosis in North American dairy herds of 40%). Of the cows identified as positive for ketosis, 64% were diagnosed between 3 and 9 days in milk and 36% were diagnosed between 10 and 16 days in milk.
Contrary to what was expected, our study found no benefit from using IV dextrose as an additional therapy to oral propylene glycol for the treatment of ketosis. We saw no benefit in terms of faster resolution of ketosis and no reduction in the risk of adverse events in the first 60 DIM. Average daily milk yield through the first 10 weeks of lactation was similar for all treatments, 94 lbs/day, 93.5 lbs/day and 94 lbs/day for propylene glycol only, propylene glycol plus 1 day of IV dextrose and propylene glycol plus 3 days of IV dextrose, respectively. More research is needed, especially with cows that have more severe ketosis (blood BHB concentration ≥3.0 mmol/L). Less than 10% of cows in our study met that criteria, and therefore our results must be interpreted with caution for this subset of cows.
Oral propylene glycol once daily has been well established by research as beneficial for the treatment of ketosis (McArt et al., 2011; McArt et al., 2012b; Gordon et al., 2013). And research by Mann et al., (2017) clearly demonstrated a faster and sustained reduction in BHB concentrations when IV dextrose was used with oral propylene glycol for the treatment of ketosis. However, the study size was small and not designed to evaluate disease and production outcomes. Our trial sought to build on that study to provide producers with solid evidence of an effective, safe and practical treatment protocol for ketosis. However, our results did not identify any benefit from the use of IV dextrose as an additional therapy to oral propylene glycol for the treatment of ketosis in dairy cows.
Based on what we currently know from research, and since administering dextrose intravenously is labor intensive and has some potential risk, we encourage producers to reconsider their use of IV dextrose for the treatment of ketosis.