COLORADO PLANTS INJURIOUS TO LIVESTOCK 
By GBO. H. GLOVER and W. W. ROBBINS 
Introduction 
Since Colorado is a mountainous state with a considerable area 
of the plains district '‘above water/’ it is reasonable to assume that 
grazing under open range conditions will always be an important 
factor in the livestock industry of the state. Poisonous plants have 
a special economic significance in the breeding and handling of 
livestock under these conditions. It is impossible to estimate with 
any considerable degree of accuracy the aggregate loss to the live¬ 
stock industry from poisonous plants, but roughly estimating the 
known losses in certain counties, we may safely assume that it 
amounts to several millions of dollars annually. 
The Experiment Station receives many letters of inquiry rela¬ 
tive to plants that are suspected of being detrimental to livestock 
and many specimens are sent for identification. This bulletin is 
calculated to assist istockmen and farmers in the identification of 
poisonous plants, to offer a few suggestions relative to preventive 
and remedial measures and to site special conditions under which 
certain plants are known to poison animals. The authors have at¬ 
tempted, by illustration and description, to correct some popular 
errors in the identification of certain plants that in appearance have 
a striking resemblance, such as the death camas and wild onion. 
Again, space is given to consideration of several plants, like algae 
and corn smut, which are incorrectly thought to be poisonous. 
CONDITIONS OF POISONING 
It is important to know the conditions under which poisoning 
is most liable to occur. There can be no doubt that animals 
when left to themselves will by instinct exercise considerable judg¬ 
ment in the selection of their food. Experience has shown that more 
animals are poisoned when being crowded by the herdsman, 
and, in case of cattle, when they are handled at the time of "round¬ 
up.” When being driven animals will grab at weeds that they would 
not otherwise touch. 
When animals are very hungry they are not very particular in 
the selection of their food. Many disastrous cases of poisoning 
occur when cattle and sheep are taken directly from the yards to 
the ranges after a long shipment. 
Larkspur, and probably some other plants, are known by ex¬ 
perience to be far more poisonous when the foliage is wet from dew, 
rain or snow. When poisonous plants, like the death camas, start 
to grow in advance of the native grasses, they are eaten almost to 
the exclusion of everything else. An acrid, bitter or otherwise dis¬ 
agreeable taste does not always bar stock from eating the first green 
