Effects of Harvest Date, Sampling Time, and Cultivar on Total Phenolic Concentrations, Water-Soluble Carbohydrate Concentrations, and Phenolic Profiles of Selected Cool-Season Grasses in Central Kentucky.

The research article explores how harvest time, cultivars (varieties of plants), and sampling time affect the concentration of phenolic compounds and water-soluble carbohydrates (WSCs) in cool-season grasses found in Central Kentucky. These factors could potentially influence horse health due to the crucial role of these grasses in their diet.

Objectives of the Study

• The primary goal of this study was to analyze the variations in the concentrations of phenolic compounds and WSCs, substances that can directly impact the health of grazing horses.
• Another aim was to map out the phenolic profile of various cultivars of cool-season grasses. Understanding these characteristics could help in developing health-promoting grazing regimens for equines.

Research Methodology

• The grass varieties studied included “Linn” and “Calibra” perennial ryegrass (PRG), “Cajun II” tall fescue (Cajun TF), “Persist” orchardgrass (OG), and “Ginger” Kentucky bluegrass (BG).
• Samples of these grasses were gathered in the morning and afternoon during the late spring season – late April, early May, and late May.
• The researchers measured the total phenolics and WSCs using high-performance liquid chromatography and assessed them using liquid chromatography paired with mass spectrometry.

Key Findings

• The concentration of WSCs was found to be higher during the afternoon sampling. This concentration also differed among the grass varieties studied and generally declined by late May.
• On the other hand, the initial high concentration of total phenolics in Calibra PRG and Persist OG either decreased or remained constant from late April to late May, except in Persist OG where it increased.
• The highest drop in phenolics in the afternoon was noticed in Persist OG and Calibra PRG.
• The phenolic profiles were found to be similar in Calibra PRG, Linn PRG, and Cajun TF, but different from Ginger BG and Persist OG.
• A variety of phenolic compounds were identified in the cultivars with significant diversity, indicating the potential for exploring their properties and how they interact with WSC, potentially impacting equine health.