Annual fall roundup for the bison herd at The Nature Conservancy's Tallgrass Prairie Preserve began in mid- October of 2004. For the third year in a row, feed trucks were used to entice the bison into the east side of the bison unit using 20% protein range cubes. When conventional ATV-based roundup began on November 1, approximately 98% of the herd already had been baited in. By November 8, the herd had been moved into the traps next to the corrals. Except for the short baiting period and the time the herd is in the corrals, where they are fed prairie hay, the herd continues to receive no food supplementation for the balance of the year. No bison were known to have escaped last fall's roundup

Bison grazing near the bison loop

Bob Hamilton, assistant director and director of science and stewardship for the preserve, reported that 2,367 bison were worked through the corral November 10-15, 2004, with disease testing of sale animals initiated on November 16. Keeper animals were given the preserve's traditional health treatments consisting of vaccination for several bovine diseases, parasite control, brucellosis vaccination of heifer calves, and year branding and electronic tagging (transponder ear tags) of all new calves born in 2004.

The only time an accurate count can be made of the year's calf crop is at roundup. During 2004, a total of 554 calves were born - 271 heifers and 283 bulls. These calves were produced by 762 females of reproductive age resulting in a 73% weaned calf crop. Following roundup, 384 animals were sold. They consisted of 37 old cows, 58 4-1/2 year-old cows, 105 2-1/2 year-old heifers, 17 mature bulls, 107 2-1/2 year-old bulls and 60 yearling bulls. The animals were sold by sealed bid and private treaty to six private bison producers in South Dakota, Nebraska, and Oklahoma

The overall average price for bison sold from the preserve was $659 per head - substantially higher than last year's $303 per head. Prices for bison have made a significant recovery from the low-point of a few years ago, but still far below what bison brought several years ago when a bred cow brought as much as $3,000 and an open cow around $2,000. Bulls used to bring considerably less than females, but more recently they have brought on average more than the females.

No trades or purchases of bison were made this past fall to add to the herd. The year-round bison unit was increased to 21,045 acres in June of 2004. The year-round cattle pasture was correspondingly decreased to 12,759 acres. The long-term bison-cattle plan calls for 11,400 acres to be devoted to cattle grazing applied research while the bulk of the rest of the preserve will be managed with bison.

The year-round bison unit will eventually occupy approximately 23,000 acres with an additional 2,278 acres used only in the fall for holding the herd during roundup. Another 2,000 acres is scheduled to be added to the year-round bison unit of 21,045 acres in late 2006. Hamilton says the herd and bison unit sizes are currently at about 90% of their desired target which is on-track to be reached by fall of 2006.

The Christina Adams Bison Herd has now been on the Tallgrass Prairie Preserve for 11 years. Since the herd's introduction on October 18, 1993, it has grown from 300 head on 4,850 acres to its current over-wintering herd of 1976 head. This year's calf crop of an expected 425 head should increase the herd to about 2,400 head this summer. The ultimate summertime herd size, including that year's calf crop, is projected at 2,700 head.

Reproductive success was slightly below last year's. The 2004 calf crop was produced by 762 females of reproductive age, resulting in a 73% weaned calf crop. There were no late-born "red calves" in the 2004 calf crop.

As reported in previous articles, the reason for reducing the projected size of the bison unit from 30,400 acres to 23,045 acres was the result of encouraging results from a two-year collaborative cattle patch burn research study on the preserve with Oklahoma State University plus the desire to invest even more landscape in the effort to export conservation friendly cattle grazing models to the ranching industry. Study results influenced the decision to increase the ultimate size of the cattle grazing area from 3,100 acres to 11,400 acres.

During Roundup 2004, a corral working crew typically consisted of seven preserve staff members, six local day-help cowboys, and one to two Conservancy personnel from the Oklahoma Chapter who operated the computer on corral working days. Roundup 2004 was the 11th annual roundup during which herd working went very smoothly in muddy conditions. The use of feed trucks to reduce animal stress and potential injury to personnel and equipment during roundup worked very well for the third straight year.

Hamilton says the corral system continues to work extremely well, and the Conservancy staff has learned how to move the animals through roundup with the least amount of stress as possible. Average processing time through the squeeze chute was 54 adults per hour and 49 calves per hour. Modifications to the corral complex in 2003 included the construction of three 1 to 5-acre holding pens adjacent to the corral on the north side. These new pens worked well for holding animals in a low-stress, native prairie environment. Enhancement made to the corral complex in 2004 included improved lighting and other electrical upgrades.

In the course of doing business on the preserve some animals will be lost to natural and un-natural causes and to known and unknown reasons. One statistic that seems to standout, however, is the fact that during 2003, five bison were lost as the result of vehicle collisions on the county road. In 2004, only one animal was lost due to a vehicle collision. This still serves as a reminder that on the open range an attitude of "safety first" cannot be over-emphasized.