Effects of Ruminal Administration of Propylene Glycol or Sucrose on Ruminal, Blood, and Hepatic Parameters in Nonlactating Cows With High Plasma Nonesterified Fatty Acid Concentrations.

Elevated blood nonesterified fatty acids (NEFA) concentration in prepartum increases the risk of postpartum diseases. This study evaluated whether intraruminal propylene glycol (PG) or sucrose (SC) administration could mitigate elevated blood NEFA induced by intravenous lipid infusion. Four nonlactating, nonpregnant Holstein cows fitted with rumen cannulas were used in a 4 × 4 Latin square design: intravenous saline infusion and ruminal administration of water (S + WT), lipid infusion and administration of water (L + WT), lipid infusion and PG administration (L + PG), and lipid infusion and SC administration (L + SC). The intravenous infusion lasted for 11 h, followed by ruminal administration 4 h after the start of the infusion. Blood NEFA concentration was increased by lipid infusion but was lower in L + PG compared to L + WT. In association with this, higher ruminal propionate and butyrate, blood glucose and insulin, and lower β-hydroxybutyrate (BHBA) concentrations were observed in L + PG. Hepatic carnitine palmitoyl transferase 1 mRNA expression was higher in L + PG and L + SC compared to L + WT. SC administration increased insulin concentrations associated with increased ruminal butyrate concentration but had a smaller NEFA-reducing effect than PG. To alleviate NEFA elevation, PG was more effective than SC, which may have involved sustained stimulation of insulin secretion of PG.