Are Feedlot-based Performance Cattle Limiting Ecological Services for Rangeland Ecosystems in Northern Mixed-grass prairies?

Are Feedlot-based Performance Cattle Limiting Ecological Services for Rangeland Ecosystems in Northern Mixed-grass prairies?

Summary

The goal of this project is to evaluate the impacts of steer frame-size and finishing time in a forage-based system. In January and November of 2016, the advisory committee met to discuss the project. The committee consists of 4 Montana ranchers who are located throughout the state. The goal of the January 2016 meeting was to outline the research project, the sampling methods, as well as discuss end-point expectations and questions. Committee members discussed the practicalities of the project, and whether or not the project was practical from a rancher standpoint. During the summer of 2016, an undergraduate student was hired to construct all fencing, as well as help put in place permanent water tanks. Four separate pastures were created, 2 which which enclosed the introduced Russian wildrye pasture that was established the previous year, and two that were larger, native range pastures.

In November 2016, the committee met once again to go out to the fields, observe the vegetation, fencing, and water availabilities, and again offer the insight. The fencing plan was changed based on some of the advice. Initial herbage mass samples were taken from all pastures, and the steers were allowed in to the Russian wildrye pastures on November 29, 2016. They stayed on the Russian wildrye pasture for about a month, and were then moved onto native range the end of December. Due to extremely cold temperatures for a prolonged period of time, steers were fed supplemental forage in order to prevent any health issues from occuring. Herbage mass, vegetation, and habitat sampling will continue to occur throughout the summer of 2017, until all animals are finished.

The group of “control” or feedlot-finished steers were put into the feedlot the same time as the forage-finished steers, and they are expected to finish sometime in May 2017.

Objectives/Performance Targets

1. Assess the economic impacts of reducing frame size of cattle finished on forage.
2. Assess the influence of cattle frame size on the capacity of conventional stocking rate models to protect or improve watersheds, wildlife habitat and rangeland condition.
3. Develop new winter stocking rate model for native ranges that will protect/promote soil health, forage quality, watershed function and wildlife habitat persistence.

Accomplishments/Milestones

We have had two committee meetings in 2017, as well as turned the forage-finishing group of steers out onto pasture. The feedlot-finished group has been placed into the feedlot at the same time, and body weights are continued to be monitored on both groups.

Vegetation, habitat, and herbage mass samples were taken in 2016, and will continue to be taken in the pasture treatments until project completion. A subset of 10 monitoring locations were randomly drawn from the 60 wildlife monitoring points established by Dr. McNew in July 2015.  Each location was permanently marked with a fiber post and GPS coordinate for long term vegetation monitoring. This approach facilitates direct comparison of changes in wildlife seasonal abundance to conditions within the plant community.  The plant community at each location was characterized by collecting information on species composition and productivity. 

o         Ungrazed monitoring locations were also established inside each of three 54 year old exclosures occurring within the study pastures. 

o         Measures of soil carbon mineralization and aboveground biomass disappearance in the three exclosures will provide a reference point for determining the effect of grazing on soil health.

Soils at each permanent location were characterized according to depth, horizon and coarse fragments.  A 50g composite sample was extracted from each soil pit, labeled and stored in the Montana State University lab for analysis of soil organic matter and texture.

A second grant was obtained from the Bair Ranch Foundation in October 2015 to track the incorporation of above ground biomass and litter into the upper soil profile.

o       A 37.5cc intact soil core was removed from a site immediately adjacent to the above ground biomass samples (see bullet below). Each core was enclosed in a capped plastic tube and placed on ice in an insulated cooler. All samples were returned to the MSU lab where they were placed in a walk-in cooler held at 2 – 4 Fo.  After a 72h stabilization period the end of the tube was opened and then placed in an incubation beaker.  The beakers were placed in a 67Fo water bath for 1h.  An atmospheric sample was extracted from each beaker and analyzed for CO2 content.  This provides and direct measure of soil microbial activity which in turn provides us with a measure of how rapidly (or slowly) soil organic matter is being mineralized.

o       This sampling protocol was repeated in March, June, Sep and December 2016

Above ground plant biomass was collected at each permanent location in December 2015.  This material was separated into green (photosynthetically active), current year standing dead, and weathered fractions.  A fourth above ground fraction, soil surface litter, was collected along with the standing material. Collections have been returned to the MSU lab, dried and weighed. This sampling protocol was repeated in March, June, Sep and December 2016. Comparison of changes in vegetation fractions to measures of microbial activity will provide a picture of how much of the material left after grazing is actually incorporated into the soil.

During January 2016, we deployed camera traps at 30 randomly selected survey locations to inventory pre-treatment habitat use by mesocarnivores (e.g., badger [Taxidea taxus], coyote [Canis latrans], striped skunk [Mephitus mephitis]) and ungulates (e.g., mule deer [Odocoileus hemionus], pronghorn [Antilocapra Americana]).

Because the steers were just placed onto pasture in November, 2016, no analysis has been completed to determine impact of frame size, or be able to identify or create any new stocking rate models.

Impacts and Contributions/Outcomes

As this study is still in it’s infancy, no significant impacts have yet been recorded.

Collaborators: