Effect of Season on Grazing Native-Grass Pastures1

A total of 2,269 mixed-breed steers (256 kg) grazed burned (April), native-grass pastures for nine grazing seasons from 1990 to 1998. Steers were allotted randomly to graze for either 1/2 season (short season [SS]) from late April to July 15 (an average of 81 d, at one steer per 0.81 ha), or for 3/4 season [intermediate season (IMS)] from late April to August 15 (an average of 112 d, at one steer per 1.21 ha). The grass species composition was measured in yr 1, 4, and 8 of the study. The economics of steers grazing the two systems were determined by stocker and feeder cattle prices at Dodge City, adjusted to southeast Kansas. The steers grazing SS gained more per day (1.26 vs 1.13 kg, P<0.01), but gained less per season (102.3 vs 126.4 kg, P<0.01). No changes in percentage species composition occurred (P>0.10) between systems for big bluestem, little bluestem, switch-grass, Indiangrass, and total perennial grass. However, percentage basal cover of perennial grass increased more for SS (P<0.05) than IMS. Grazing system did not appear to have a negative effect on grass composition during the 8-yr period. Return per steer was greater for steers stocked at IMS (P<0.10). This was a result of more gain over which to spread start-up costs.