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VALUE OF CACTI AS FOOD FOR STOCK. 11 



FOOD VALUE OF DIFFERENT PARTS OF THE PLANT. 



The opinion is prevalent in southern Texas that the old woody- 

 stems of Opuntia lindheimeri fed there are much more valuable as a 

 stock food than the j-ounger growths. So fu-mly do many l^elievc 

 this that they practice cutting off and throwing away two or three of 

 the terminal joints when feeding. In Mexico, on the contrary, the 

 young growth is always fed; but there the species are conunonly 

 much larger and stouter, and the trunks are altogether too woody 

 to be fed even if it were desirable to do so. The reasons for the opin- 

 ions current in Texas are rather clearly brought out in the analyses. 

 The younger growth has a relatively higher water content, and there- 

 fore probably causes more scouring, which is the only evil influence 

 overcome by a rejection of it. On the other hand, the old stems 

 contain a jnuch larger proportion of liber and are really of less forage 

 value. 



Guthrie,'^ after comparing liis owti analysis of the stems of four 

 Australian species with the analysis of fruits nuideby Wolf, concludes 

 that the latter are of less forage value than the stems, because they 

 contain a smaller proportion of nutritious substance and more crude 

 fiber. Forbes,^ on the other hand, concludes from analyses of Ari- 

 zona cylindrical-jointed species that the fruits of these species are 

 relished by cattle on account of their high ether extract (including 

 fats). Our analyses show that the ether extract is nuxinly a constit- 

 uent of the seeds, and since these pass through cattle undigested can 

 contribute nothing to either the palatability or nutritive value of 

 this part of the plant. That the seed is not digested is plainly shown 

 in the case of Opuntia lindheimeri in many favorable seasons in por- 

 tions of Texas. In the vicinity of Austin, in the early spring of 1904, 

 there were numberless young plants springing up from cattle drop- 

 pings in many of the pastures. They were fully as numerous in some 

 situations as are the seedlings of the mesquite under similar condi- 

 tions in favorable seasons in the river valleys of Arizona and on the 

 plains of southern Texas. 



This applies to the genus Opuntia, to which belong the prickly 

 pears and cane cacti. The seeds of the other group are very different 

 in character. There is no doubt that burros, which commonly feed 

 upon the fruits of the viznaga {Ecliinocadus wislizeni) , get a great deal 

 of nourishment out of the seeds, which are very oily and easily masti- 

 cated. It is interesting to note that No. 8170a {Opuntia fulgida) 

 contains but little more food value in the whole fruit than is found 

 in the pulpy portion alone, but in this sample most of the seeds were 

 poorly developed or sterile. Other samples of fruit of the same 

 species show an apparently greater food value. 



o Agricultural Gazette, New South Wales, 11: 671. 1900. 



i) Arizona Agricultural Experiment Station, Annual Report, 15: 496. 1904. 



102-1 



