Sustainable and profitable control of invasive plant species by small ruminants

2005 Annual Report for LS05-175

Project Type: Research and Education
Funds awarded in 2005: $178,000.00
Projected End Date: 12/31/2009
Region: Southern
State: Texas
Principal Investigator:
Dr. James Muir
Texas A&M AgriLife Research

Sustainable and profitable control of invasive plant species by small ruminants


Both overgrazed small ruminant rangeland and invasion of aggressive vegetation are environmental concerns in the southeastern USA, St. Croix, and Puerto Rico. This project proposes to address plant:animal interface concerns to resolving both issues by expanding the use of small-scale commercial flocks to control invasive weeds. How this is done effectively, on what species and at what cost will be addressed in five representative locations throughout the southern SARE region. Intensive, short-duration goat/sheep browsing (ISDGB) techniques for controlling weeds is the goal.

Objectives/Performance Targets

1) Develop ISDGB trials that address flock owner/landowner questions and serve as local demonstrations of this method for environmentally sustainable invasive plant control.
2) Research specific plant:animal interface issues that will develop into the techniques that effectively control of permanently eradicate invasive plants in each environment and for each species, including stocking rates, seasonal vulnerability, browsing duration, and negative effects on both native vegetation and flock performance.
3) Develop farmer-to-farmer contacts, demonstrations, brochures, popular press articles, web pages, and refereed articles to foment greater commercial application of ISDBG in the region.
4) Assist both landowners and goat/sheep flock mangers in determining equitable cost sharing (economics) for the commercial application of ISDGB.


Group: Attended planning meetings at Stephenville, Texas (21-22 April, 2005; 10-13 February, 2006) and Booneville, Arkansas (8-10 January, 2006) to discuss project implementation and landowner/flock manager concerns.

First-year data was collected from an on-station trial using producer-acquired goats browsing hardwoods dominated by an understory of greenbriar (Smilax spp.). Two brush-management treatments, three stocking rates, and four post-ISDBG vegetation treatments were superimposed. Two off-station locations (Brown and Erath Counties) have been identified (target species include mesquite and cedar) for additional trials that focus on land preparation methods and timing. The on-station trial will be repeated again in 2006 while the on-farm trial will be initiated as soon as mesquite leaves out in spring 2006 and continue on for 12 months. Visits to FVSU, St. Croix and Mayaguez are planned for 2006 to assist with project planning and coordination. A web site has been designed and will be uploaded as soon as A&M review and approval is given.

Fort Valley State University:
A sub-contract was set up in mid-2005 that allowed project efforts to commence. Measured off plot areas, purchased animals (goats) and materials for both permanent (FVSU funds) and temporary (SARE) fencing and watering systems for the grazing kudzu-invaded areas. Dead material on the plots was removed by burning on 3/24/06. Construction of fences, watering system for the plot area is expected to be completed by May 15, 2006.

St. Croix:
Contacts have been made with both landowners (invaded with weeds) and goat owners to set up off-station trials. Sub-contracts were finalized in early 2006 that will allow work to be initiated.

A sub-contract was finalized in mid-2005 to provide funding for research in southern Florida. Due to a change in producer priorities, the work to be done in north Florida was transferred to FVSU. On-station trials were initiated in 2005 in southern Florida. At low stocking rates in Brooksville FL, goats did not prefer weedy species to perennial peanut when allowed continuous access to the pastures. Pasture size will be reduced and a rotation imposed in an attempt to increase consumption of weeds.

University of Puerto Rico:
Sub-contract was set up to provide funding for research and outreach. In the fall of 2005, mature goats browsed in a pasture that contained 25% mature trees of White Acacia. Visual observations were taken on damage to the bark of the trees. Goats continuously browsed and formed a ring on the stem of the tree causing it to eventually dried and die out.

At Gurabo, a high rainfall area in Puerto Rico, replicated plots containing 50% young White Acacia (2-m height and 5-cm stem thickness) were fenced (UPR funds) and will be browsed with mature goats in the spring of 2006. Another replicated study will assess effects of mature goats on Catclaw (Mimosa pigra) in the summer of 2006.

Impacts and Contributions/Outcomes

At all locations, on-farm cooperators (both landowners suffering from weed invasion and flock managers looking for additional income generation opportunities) have become aware of the potential for ISDGB as a novel agricultural activity. Landowners are aware that goats can control invasive weeds, but they do not know how to implement this approach nor how to incorporate this as an additional income-generating activity off-farm.


Tom Terrill

Fort Valley State University
Elide Valencia

Professor of Forages
University of Puerto Rico
Stuart Weiss

Forage project director
USVI Agricultural Experiment Station
University of the US Virgin Islands
Sam Coleman