18 



BULLETIN 1170, U. S. DEPARTMENT OF AGRICULTURE. 



must be increased so that the cattle will have an abundance of feed 

 before them at all times, and as a result the per- acre gain will be 

 reduced. While a high individual gain per acre might on casual 

 consideration appear to be the most desirable measure of efficiency 

 of a pasture or system of grazing, other factors should not be under- 

 estimated. For example, the vegetation in the 30-acre pasture has 

 been injured by the close early grazing. This factor, however, does 

 not lend itself readily to definite measurement, because it is cumu- 

 lative and may not be apparent until a pronounced reduction has 

 occurred in the grazing capacity of the area. This effect is best 

 determined by the seasonal gains per head of the cattle and the con- 

 dition of the vegetation. The injury to the vegetation must be given 

 relative consideration with the cattle gains, either per head, total per 

 acre, or individual per acre, in the determination of a measure of 

 efficiency of a grazing system. Another factor of much weight is 

 the time of removal of the cattle from a pasture. A system of graz- 

 ing that makes it necessary to remove the cattle from a given area 

 by the middle of July or August in order to procure the maximum 

 gain from it is not to be commended. The cattle are not ready or 

 in the best condition for market at this time, nor is it desirable to 

 start them in the feed lot so early in the season. If another pasture 

 is to be provided for them, it would be better to enlarge the first one 

 or reduce the number of cattle and graze it in such a manner as will 

 carry the cattle the full season. This arrangement would also result 

 in better gains per head. 



Table 4. — Average daily gains of 2-year-old steers for the period during which 

 the 30-aere pasture was grazed in the years 1916 to 1921, inclusive. 





Days 

 grazed. 



Average daily gains per head (pounds). 



Year. 



100 acres. 



70 acres. 



50 acres. 



30 acres. 



Rotation 



(70 acres). 



1916 



150 

 115 

 105 

 90 

 90 

 115 



1.93 



2.08 



2.04 

 2.24 

 2.27 

 2.70 

 2.41 

 2.22 



1.86 

 1.08 

 1.48 

 1.99 

 1.96 

 1.47 





1917 



2.37 ; 1.98 

 2.31 2.44 





1918 



2.11 



1919 



2.55 

 2.77 

 2.19 



2.92 

 2.82 

 2.42 



2.96 



1920 



2.76 



1921 



2.18 







Average 



111 



2.35 



2.44 



2.31 



1.64 



2.50 











In order to determine the most efficient system of grazing it is 

 necessary to formulate a measure by which a pasture can be judged. 

 Such a measure must include all the factors with which the problem 

 of grazing is intimately concerned. If a single measure, such as the 

 gains per head or per acre, is used, other factors which are correlated 

 with it will not be given sufficient consideration. Therefore, the 

 most efficient system of grazing is one that will insure sufficient 

 forage during the entire season to produce the greatest total gain, 

 with the least number of cattle on the minimum unit of land, without 

 permanent injury to the native vegetation. The system of grazing 

 that most nearly fulfills this measure of efficiency may not be the 

 one that produces the maximum gain per head or the greatest 

 individual gain per acre. In order to fulfill its requirements the 



