EFFECTS OF DIFFERENT SYSTEMS OF GRAZING. 15 



gains produced in the latter two pastures during the 47-day period, 

 as compared with the earlier gains, indicate that the fall or mature 

 condition of the vegetation may have a pronounced influence upon 

 the gain. However, the gains made by the steers from the 30-acre 

 field during the same period on the reserve pasture strongly indicate 

 that the condition of the cattle exerts an influence on the gains as 

 great as or greater than that due to the condition of the vegetation. 

 The cattle on the 100-acre and the 70-acre pastures have been on full 

 feed all summer. They have therefore been able to put on the maxi- 

 mum gains which the native vegetation is capable of producing by 

 the time it is fully mature. The steers on the 30-acre pasture, on the 

 other hand, have been forced to graze a short range and have there- 

 fore not been able to make the maximum gains which an abundant 

 supply of native vegetation is capable of producing. Therefore, 

 when they obtain full feed in the reserve pasture they are in a con- 

 dition to put on gains more rapidly than steers that have been on 

 full feed up to that time. The fall gains of these steers are all the 

 more remarkable when it is considered that they are made notwith- 

 standing the general tendency to shrink during cool weather. 



PERCENTAGE OF VEGETATION ANNUALLY REMOVED BY 



GRAZING. 



Table 3 shows the estimated percentage of foliage cover annually 

 removed from the different pastures by grazing. The quantity 

 removed is estimated, because any more exact measurement, such as 

 mowing, would disturb the condition of the pasture more than the 

 annual grazing. When no vegetation is removed, as in an ungrazed 

 pasture, there is 100 per cent foliage cover for the season. If all 

 the vegetation has been consumed by the grazing cattle 100 per cent 

 has been removed. Other estimates are based on these two condi- 

 tions. Plate I shows two conditions of the same area, Figure 1 show- 

 ing the pasture when it was estimated that 15 per cent of the vege- 

 tation had been removed, and Figure 2 the same area later in the 

 season when it was estimated that 65 per cent of the vegetation 

 had been removed. It is recognized that the personal equation influ- 

 ences any estimate, but the fact that the estimates have been made 

 by the same person for the different seasons increases their value. 

 However, the relative quantities are the important factors and show 

 clearly the degree of grazing. In the 100-acre pasture the average 

 proportion of foliage cover that has been removed is 51 per cent. 

 This fact would almost lead one to assume that grazing at the rate 

 of one head to 5 acres would furnish sufficient feed for the season. 

 However, the 50-acre pasture shows that this is not enough, as the 

 cattle lose weight because their feed is gone before the end of the 

 season. The 70-acre pasture, with an annual average of 71 per cent 

 of the foliage cover removed by grazing, has produced sufficient 

 feed to carry the cattle through the season with maximum gains per 

 head. This would strongly indicate that in order to insure sufficient 

 feed and not overgraze under a system of continuous grazing, from 

 15 to 25 per cent of the foliage cover should remain on the pasture 

 at the close of the season. To make a greater utilization of the for- 

 age a different system of grazing must be adopted. Since the num- 

 ber of cattle has been increased in the rotation pasture, over 90 per 



