Sunday, January 24, 2010
Testing elk for brucellosis
Today I accompanied the Wyoming Game and Fish Department to photograph the process of testing elk for brucellosis. The testing program, in its fifth and final year, takes place at three elk feedgrounds on the western flank of the Wind River Mountains. I've covered the testing program every year for various media.
The photo above shows the elk trap - a huge wooden corral setup, at the Muddy Creek elk feedground.
Brucellosis is an incurable highly contagious disease associated with the reproductive tract, so only adult female elk are tested. All bulls and calves are released (although eartags are placed in the calves' ears for future identification if needed).
The photo above shows the chutes elk are processed in. After being moved from a large round corral, they are pushed into alleyways, and groups of about six are separated into paneled boxes, and eventually sorted into individual chutes, where they can be "squeezed" and handled.
Blood samples are drawn from a vein in the neck. If the individual elk is excessively nervous, a blindfold is used to help calm her. I liked how this elk remained rather calm, but never took her eye off the biologist working on her.
A calf is released from the chute after an eartag was inserted into its ear.
These adult females have all been processed and will be held overnight in the trap, awaiting their fate. Each blood sample has a number that corresponds to the rubber tags around the cow's necks. Animals that test positive for brucellosis will be sent to slaughter, and the remainder will be released back onto the feedground.
The test-and-removal program is a five-year effort aimed at reducing the presence of the disease brucellosis in elk herds along the western front of the Wind River Range. Brucellosis is a contagious disease that causes abortions in hoofed animals and is present in elk and bison in the Yellowstone region. Brucellosis transmitted by Muddy Creek feedground elk to a neighboring cattle herd in 2003 resulted in the slaughter of the entire cattle herd. Several other cattle herds were later destroyed for the same reason, and transmission from elk was indicated in all cases.
Brucellosis can also be transmitted to humans - right off the top of my head I can name five people I personally know who have had it (three vets and two ranchers). It's a horrible disease, and as many of you know, is subject to control efforts throughout the world. Some hospitals in Central Asia have entire wards dedicated to treating patients with this disease.
Brucellosis seroprevalence rates in elk using the Muddy Creek feedground have progressively decreased from 37 percent to seven percent in the first four years of the program.