The crabgrass was grazed with a two-herd approach. Stocker steers were managed as first grazers; bred replacement heifers, second grazers.

The second-grazer heifers were crossbred, home-produced, and fleshy from rye pasture and early bermudagrass grazing. They weighed 968 pounds initially. All veterinary procedures were completed before the crabgrass grazings. From a complete mineral mix for our region, the heifers were provided a free-choice loose mineral mix of one-third salt and two-thirds mineral. Flies were controlled with a fly wipe charged with a diesel/Co-Ral (coumaphos) insecticide mixture.

The first grazer steers were purchased at a single regional livestock sale and were mixed breeds and crossbred cattle with an initial average of 387 pounds per head. The day after they were bought, they were received, processed, and put to crabgrass pasture. We prefer to receive steers the day of purchase, but it was not feasible in this case.

To minimize stress and reduce feed and hay costs in the receiving lot, all veterinary procedures were completed the day cattle were received. The procedure has worked almost perfectly for several years and there have been no deaths.

The receiving and veterinary practices were as follows: brand, castrate, attach a number and fly ear tag, dehorn, deworm with Ivomec F, implant with Ralgro, and vaccinate with seven-way blackleg with Haemaphilus somnus, Cattlemaster 4 and five-way leptospirosis, Pasturella haemolytica, and Micotil (antibiotic). The steers did not receive any feed or hay during receiving. Booster shots were given two to four weeks later for seven-way blackleg with Haemaphilus somnus, and Cattlemaster 4 and five-way leptospirosis. All steers remained healthy and no retreatments were needed. The steers were dewormed again in early August after fecal counts showed roundworms and liver flukes. A mix of Safeguard and Curatrim was used. On pasture, steers received a free-choice loose salt and mineral mixture: one-third salt and two-thirds mineral from a complete mineral for our region.

Steers were on grass alone the first three weeks. As midsummer heat and dry weather started, 1.1 pounds of an all-natural 38 percent crude protein cube containing the ionophore rumensin was fed each steer Monday through Friday, with double the normal rate on Monday and Friday. All feeding was done on the ground under one-wire electric paddock division fences. Research has shown this feeding technique usually can increase gains on perennial summer grass 0.2 to 0.5 pound per day. We do not know the ratio of added gain on the higher-quality summer crabgrass forage but surmise it does increase performance somewhat and the technique is consistent with that of managing for top gains on crabgrass.

Figure 1. First grazer and top grazer steers on abundant 'Red River' crabgrass. Steer grazings were similar to this from June to August. September grazing was less abundant and on dry forage.

Crabgrass was 3 to 8 inches tall and ready to graze after the rye winter crop, about June 8. Actual grazing was uncontrollably delayed until June 22, at which time the forage was 12 to 18 inches tall and much above optimum height.

The crabgrass was in a four-paddock grazing cell, which was not optimal, but the low number was helpful. We would have preferred something closer to a twelve-paddock grazing cell.

Remember, the major goal of this trial was to manage steers a bit differently to try to produce upper-level ADG, so they always were rotated to the best crabgrass paddock. The steers were first grazers and topgrazers, weighing 361 pounds per head initially. They always were fed the first grazings of a paddock and those of a paddock's regrowth (figure 1) and never had to graze crabgrass short; therefore, the volume of their forage was always good.

Crabgrass forage was lush to green for the first six to seven weeks (60 percent) of the crabgrass season. Crabgrass in the last portion of the season was overmature and severely drought-stressed and later dried and dying, but the volume was good.

Overmature crabgrass obviously has lower quality than younger grass and also is less productive; total yield can be reduced by approximately 35 percent (see comments under "Weather"). Better grazing management probably would have increased yields.

Managing the steers as first grazers and topgrazers produces the best ADG because they select the best-quality forage and consume the most mass by taking the biggest bites possible. Thus, quality intake is maximized. Our research and that of others illustrates that performance increases about 40 percent with these techniques. We believe the ionophore feed discussed before also increases ADG.

Replacement heifers were second grazers (figure 2) that were grass fat, going onto crabgrass pasture at an average weight of 968 pounds per head. Their job was to graze crabgrass residue left by the steers, preparing the paddocks for higher-quality regrowth for the steers. We let them topgraze the residue before grazing it to about 3 inches. Their final job was to finish grazing all the useful crabgrass residue to prepare the field for the next cereal rye crop (figure 3). Second grazer heifers did not necessarily follow the steers directly. We rotated them to paddocks to graze residue we thought needed it next.

Precipitation and, therefore, soil moisture was good from the September rye planting throughout the rye grazing season. Moisture for crabgrass was excellent to good from late April to mid-July but deficient from mid-July to the mid-September conclusion of the trial. The total rainfall during the last two months of the crabgrass season was 2.5 inches, with none of it a soaking rain. These weather trends need to be considered along with the performance information.