Quantifying Secondary Compounds in Common Pasture Vegetation for Behavior Based Grazing Management in Hawaii

Quantifying Secondary Compounds in Common Pasture Vegetation for Behavior Based Grazing Management in Hawaii

Summary

Work in 2011 was focused on expanding the secondary plant compound database, which now contains 45 plants with secondary compounds of interest. From the database we selected 27 plants to form a list of range and pasture plants for collection and further analyses (see attached). Nineteen of these 27 plants have been collected and dried for analyses of selected secondary compounds. Analyses of these plants are pending identification of suitable laboratories that can analyze secondary plant compounds. While some laboratories have been identified for some compounds (i.e. alkaloids, tannins), not all laboratories can analyze for the whole suite of compounds we are interested in. Work continued to collect, press and mount plant specimens from the range and pasture secondary plant compound list for inclusion in the range and pasture plant herbariums located at Maui and Hawaii County Extension Offices. Currently the Maui County Extension Office range and pasture plant herbarium contains 15 species from the list, while the samples of the same species for Hawaii County are collected, pressed and ready for mounting. Work has started on a field manual of Secondary Compounds in Pasture Plants of Hawaii (see attached example pages). This manual will provide common and scientific names of each plant in the manual along with a brief description of the plant for field identification. The manual will also provide a summary of the secondary compounds and forage value of the plants along with recommended targeted grazing practices and cautions for utilization of the plant.

• Secondary Plant Compound List

• Sample Page

Objectives/Performance Targets

The specific objectives for this project are:

1)Develop an online database accessible to the public listing common range and pasture plants, their nutritional value, secondary compounds and recommended grazing practices for utilization.

The database is fully populated with 45 plants. Twenty-seven of the plants have been selected for analyses of specific secondary compounds. Samples of 19 of these plants have been collected and prepared for analyses. The database is not currently ready for public access.

2)Establish a plant collection of the species in the database for identification and educational purposes that will be held in the Range and Pasture Plant herbariums located at the county extension offices in Hawaii.

Fifteen plants specimens have been collected, pressed, mounted and are on display at the Maui County Extension Office. Fifteen plant specimens have been collected and pressed and await mounting at the Hawaii County Extension Office.

3)Produce a field manual for producers and land managers providing information on the plants in the database that will be useful for field identification of the plants and will also provide a summary of secondary compounds, forage value, recommended targeted grazing practices and cautions for utilization of the plant.

Production of the field manual on Secondary Compounds of Pasture Plants in Hawaii is underway.

4)Develop targeted, behavior-based grazing practices for the plants in the data base that will be presented in a series of fact sheets and extension service workshops.

Information on targeted, behavior-based grazing practices is being compiled to be included in the database and in the field manual, as well as fact sheets and workshop presentations.

Accomplishments/Milestones

The Secondary Plant Compound database has expanded from 20 plants in 2010 to 45 at the end of 2011. In addition, 15 plant specimens have been collected from Maui and Hawaii County pastures for display in the Range and Pasture Plant Herbarium in the county extension offices. A total of 19 plant samples have been collected from Maui and Hawaii County pastures for analysis of selected secondary plant compounds. Analyses are pending identification of appropriate laboratories for conducting the analyses for the specific compounds of interest. This has proven more difficult than first realized. Work on the field manual, Secondary Compounds in Pasture Plants of Hawaii, has begun along with compiling specific targeted, behavior-based grazing practices for the utilization of these plants.

Impacts and Contributions/Outcomes

The information and knowledge gained from this project will assist livestock producers in the identification of common plants found in most pasture systems in Hawaii that contain certain secondary compounds and provide recommendations for the utilization of those plants using targeted, behavior-based grazing management practices. For example, certain plants contain secondary compounds that can be beneficially utilized to neutralize more toxic compounds found in other plants. Tannins, for example, have been shown to neutralize the toxic effects of certain alkaloids found in tall fescue in the mid-west when consumed prior to the animal grazing the tall fescue pasture. The utilization of the knowledge and information from this project will help livestock producers make informed decisions about the sustainable management of their range and pasture systems.

Collaborators: