A comparison between propylene glycol and a multiple component drench on energetic variables in early lactating Holstein cows

Abstract Text: Gluconeogenic precursors are therapeutically administered to treat ketosis in early lactation dairy cows and frequently provided as a standard management practice on all fresh cows.  Study objectives were to compare and contrast a multiple component drench (MCD) containing glycerol, propylene glycol, calcium propionate and water to propylene glycol (PG) on circulating glucose, insulin, NEFA, and β-HBA. Lactating Holstein dairy cows (n=24, 11.6 ±1 DIM; parity 1 to 7) were utilized in a replicated experimental design. Cows were randomly assigned to receive one of four treatments: 1) control (300 ml water), 2) 300 ml of PG (Propylene Glycol USP/EP, Dow Chemical Company, Midland MI), 3) 300 ml (M-MCD; TechMix, Stewart MN), and 4) 360 ml (H-MCD; TechMix, Stewart MN).  The PG and H-MCD treatments were designed to provide a similar amount of gluconeogenic precursors. Cows were fasted for 4 h and then received a rumen drench of their respective treatment at 0800 h. All products were administered using an orogastric tube to assure successful rumen delivery and chased with 100 ml of warm water.  Blood samples were collected via a jugular catheter at -15, 0, 15, 30, 60, 90, 120, and 150 minutes relative to treatment administration. Metabolite and hormone responses were calculated as area under the curve (AUC) by linear trapezoidal summation between time coordinates after subtracting their respective baseline values. Compared to controls, PG, M-MCD and H-MCD all increased (P<0.01) circulating glucose following the drench, but the glucose AUC did not differ between treatments. The insulin response peaked at +30 min in the PG, M-MCD and H-MCD the overall response was similar amongst treatments. Compared to controls, PG, M-MCD and H-MCD all markedly decreased (P< 0.05) NEFA (42% at +120 min) and NEFA nadir occurred 60 min following treatment administration. Compared to controls, all three treatments decreased β-HBA, but PG tended (P<0.09) to decrease ketones more than M-MCD and H-MCD. In summary, although variable, all three gluconeogenic precursor treatments influenced energetic variables and thus the MCD product appears to be a viable strategy to manage energetic deficits in early lactation.

Keywords: Dairy cow, propylene glycol, multiple component drench