# Effects of Preventive Administration of Propylene Glycol or Sucrose in Dairy Cows with Elevated Blood Non-Esterified Fatty Acids During the Close-Up Period

## TL;DR

Administering propylene glycol or sucrose to dairy cows with high fatty acids before calving improves their health and reduces culling after birth.

## Contribution

This study demonstrates that prophylactic administration of propylene glycol or sucrose improves energy metabolism and reduces postpartum culling in high-risk dairy cows.

## Key findings

- Propylene glycol and sucrose reduced non-esterified fatty acids and improved energy metabolism in treated cows.
- Both treatments significantly decreased postpartum culling rates compared to untreated controls.
- Propylene glycol showed more consistent improvements in blood profiles and liver function.

## Abstract

The objective of this study was to evaluate the effects of administration of propylene glycol (PG) or sucrose (SC) on health and production outcomes in dairy cows with elevated non-esterified fatty acids (NEFA) levels of 0.3 mEq/L or higher during the close-up period. Thirty-five cows from two farms in Hokkaido were assigned to PG, SC, or untreated control groups, with treatments administered for 5 days starting from the blood testing. In PG and SC cows, blood profiles related to energy metabolism, including NEFA and β-hydroxybutyrate concentrations, improved after calving compared with controls, and liver function was maintained as well. Cows in both treatment groups exhibited significant decreases in postpartum culling rates. These findings suggest that prophylactic administration of PG or SC may contribute to postpartum productivity.

The purpose of this study was to evaluate the preventive effects of propylene glycol (PG) or sucrose (SC) in dairy cows with high levels of non-esterified fatty acids (NEFAs) during the close-up period. From July 2021 to August 2022, blood samples were collected from 193 cows between 14 and 7 days prior to the expected calving date in two farms, and 35 multiparous cows with serum NEFA ≥ 0.3 mEq/L were randomly assigned to PG (500 mL/day, n = 11), SC (1000 mL/day of 50% solution, n = 11), and untreated control (HC; n = 13) groups. Treatments were administered orally for 5 consecutive days. Compared with HC cows, the serum NEFA concentration tended to be lower in SC cows at 3 days in milk (DIM) and was significantly lower in PG cows at 14 DIM. Serum β-hydroxybutyrate concentrations tended to be lower in SC cows at 21 DIM. Blood glucose concentrations were higher in both treatment groups at 3 DIM, and the serum total bilirubin concentration remained lower until 14 DIM in PG cows and until 7 DIM in SC cows. At 7 DIM, PG cows showed significantly higher total very low-density lipoprotein levels and PG and SC cows had significantly or tendentially higher low-density lipoprotein triglyceride concentrations. Cows in both treatment groups had significantly reduced culling after calving. These results suggest that prophylactic administration of PG or SC improves energy metabolism by supporting liver function, thereby reducing postpartum culling, with the PG group showing a more consistent effect.