USE OF ANNUAL PLANTS IN CALIFORNIA FOOTHILLS 



11 



forage they take without discrimination between species. As most of 

 the plant growth occurs during short rainy periods, cattle obtain the 

 greatest amount of green forage immediately following rains. In years 

 with limited fall precipitation or with dry, freezing weather in the winter, 

 for several weeks at a time cattle must depend largely on the old roughage 

 whose value has been lowered through leaching. Because growth of new 

 plants during the fall and winter is so uncertain, it is advisable to have 

 sufficient old grass on the ground in the fall to serve as a source of roughage 

 in the years when it is needed. 



Supplemental feeding is necessary in this period of uncertain plant 

 growth. After rainy periods the crude protein in the cattle diet may be 

 above 10 percent; but when new plant growth is retarded and the cattle 

 are forced to eat more old roughage, the percentage of crude protein is 

 lowered (12) . 6 Also, throughout the fall and winter the total intake of 

 dry matter is reduced because the cattle spend most of their grazing 

 time in search of succulent green forage. Thus, supplemental feeds are 

 needed to supply both protein and carbohydrates. Inadequacy of the 

 forage alone was shown by weights of yearling heifers that did not 

 receive supplemental feeds. As an average for 12 years the heifers 

 weighed almost the same at the end as at the start of this fall-winter 

 period. 



1 1 1 i 1 1 



1934 

 1935 

 1936 

 1937 

 !938 

 1939 

 1940 

 1941 

 1942 

 1943 

 1944 

 1945 

 1946 

 1947 



AV6. 



Y/////////J 





SEPT. 



OCT 



NOV. 



DEC. 



JAN. 



FEB 



MAR. 



1935 

 1936 

 19 37 

 1938 

 1939 

 1940 

 1941 

 1942 

 1943 

 1944 

 1945 

 1946 

 1947 

 1948 



Figuhe 5. — Variations in length of time that green forage was inadequate on foothill 



range. 



The length of time that green forage was inadequate during each 

 plant-growth season at the experimental range is shown in figure 5. 

 Start of the period of inadequate green forage was closely related to the 

 date of the first effective autumn rains of 0.5 to 1.0 inch, or more. End 

 of the period is the date when cattle were placed in the grazing-intensity 



6 Italic numbers in parentheses refer to Literature Cited, p. 51. 



