598 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



may occur. If certain poisonous plants start to grow in the early 

 spring before the native grasses and offer a considerable amount of 

 succulent material, sheep and other stock are naturally tempted to 

 eat them, especially if it is difficult to obtain a sufficient quantity of 

 grass. It sometimes happens that poisonous plants closely resemble 

 grasses in general appearance. This is true of death camas before 

 flowering, and since such plants grow mingled with grass it may be 

 possible that they are unintentionally eaten along with the grass. 

 During seasons of great drouth the native grasses mature earlier in 

 the season than usual and soon become dry and unpalatable, while a 

 number of other plants remain green and somewhat succulent for a 

 longer period. This statement is especially true of certain legumin- 

 ous plants, such as loco weeds and lupines. The loco habit is apt to 

 become established in lambs during dry seasons. Lambs are more 

 affected by drouth than the older sheep, and insist upon having some 

 succulent forage. During dry seasons they may be able to find such 

 forage only in loco weeds and other similar plants. 



The stage of growth of the plant determines largely whether it 

 will be eaten at a given time or not. For instance, larkspur and 

 water hemlock become so coarse during their later stages that they 

 are seldom, if ever eaten by sheep ; and some plants, as the death ca- 

 mas and purple larkspur, turn yellow and shrivel up very soon after 

 flowering, and in such condition they are not tempting and are sel- 

 dom eaten. 



So far as it has been possible to determine by observation, the 

 taste and smell of poisonous plants have little, if any, influence in de- 

 termining the extent to which they are eaten. It must, of course, re- 

 main entirely doubtful whether plants which have an exceedingly 

 disagreeable taste for us affect stock in the same manner. The taste 

 of larkspurs is disagreeable and even nauseous to man, but they are 

 frequently eaten in large quantities by sheep, cattle, and other ani- 

 mals. The death camas possesses a bitter principle and the juice pro- 

 duces an irritation of the mouth cavity, which persists for an hour or 

 more and causes increased salivation. It was impossible, however, to 

 get any evidence that the bitter taste had any influence upon the fre- 

 quency with which the plant is eaten by the stock. From a theoret- 

 ical standpoint it might be plausible that the taste and odor of plants 

 largely determine their use as food by stock, and further observations 

 on this point may lead to some definite conclusions in the matter. 



The problem just stated may be somewhat affected by observed 

 variations in feeding habits of stock with reference to poisonous 

 plants. It seems impossible to make any definite statements with re- 

 gard to this matter, or even to predict from one year's observations 

 what will be the feeding habits of sheep for another season. It is ob- 

 served that during some seasons the purple larkspur is eaten in large 

 quantities by sheep and other animals with serious consequences, 

 while during other years the same sheep may walk over conspicuous 

 areas of this plant without touching it. A striking variation is also ob- 

 served in the feeding habits of a single band of sheep. One sheep may 

 feed almost exclusively upon a certain plant which is scrupulously 



