12 CIRCULAR 804, U. S. DEPARTMENT OF AGRICULTURE 



although very palatable, were available largely in summer and there- 

 fore supplied forage only temporarily. The most important browse 

 species furnished only a small amount of forage in summer and fall. 

 These species are of greater importance for winter grazing. 



The very palatable Sandberg bluegrass and threadleaf sedge were 

 readily eaten by the sheep in spring and early summer and again in 

 the fall when new growth appeared. At these seasons but particularly 

 in early spring, these two species supply a high percentage of the forage 

 for sheep. Bluestem was relished when it was fresh and green in early 

 summer and again in the fall, when rain or snow softened the cured 

 leaves. The ripe seed heads were particularly well liked at that time. 

 The new growth of needle-and-thread was well liked, but the sheep 

 did not graze this species after the plants produced heads unless new 

 fall growth was produced following August or September rains. Blue 

 grama and buffalograss were grazed throughout the summer and to 

 some extent in the fall, depending upon weather and snow conditions. 

 A greater variety of succulent vegetation was available in early sum- 

 mer than at any other season. The flowers of weeds were particularly 

 attractive to the sheep. 



Besides the grasses and forbs, several browse species regularly made 

 up a substantial part of the forage. The various species of sagebrush 

 and saltbush were frequently browsed, and winterfat and rose were 

 also readily taken. The sheep also ate the fruit of skunkbush sumac 

 and black chokecherry. Many of the late-blooming forbs were palat- 

 able to the sheep, and their appetites for these species and the various 

 browse plants increased as the grasses cured with the advancing season. 



How the Forage Was Utilized 



Obtaining a reliable appraisal of grazing use on a range involves 

 observations of large numbers of individual plants of the most impor- 

 tant forage species. The measurement of grazed stubbles and a tally 

 of numbers of key plants grazed along transects drawn as chords of 

 concentric circles around the central well provided a basis for apprais- 

 ing herbage utilization on the experimental sheep ranges. Previously 

 recorded ungrazed plant heights and height-weight tables for each 

 species made possible the conversion of stubble heights and percent- 

 ages of total numbers of plants grazed to percentage of herbage, 

 figured to ground level, removed by grazing. 



The important forage plants were grazed to a low stubble height 

 (table 4) in all pastures even though more range acreage and forage 

 were available for each sheep under conservative and light stocking 

 than under heavy stocking. Variations in utilization between pas- 

 tures stocked at different intensities resulted more often from differ- 

 ences in the percentage of the total number of plants that were grazed. 

 This percentage varied with degree of stocking, height growth of the 

 individual plants, succulence of the herbage, weather, and other 

 factors. Height growth was an important factor affecting utilization 

 from year to year even though grazed stubbles and percentage of the 

 number of plants taken remained fairly constant. Regrowth after 

 early fall rains complicated appraisal of utilization, particularly in 

 threadleaf sedge. In this species it could not be distinguished from 

 spring growth and its occurrence lengthened grazed stubble . height 

 and reduced percentage utilization. 



