Species and taxonomic differentiations between species are insufficiently characterized.
Different lupines produce varying syndromes in a a given species of livestock.
Seasonal variation in toxicity in a given species of lupine exist and many species are acceptable forage under range conditions. Plants which are in the preflowering stage of maturity are unlikely to be hazardous, under normal range circumstances, except in the case of L. leucophyllus which may cause toxicosis as a result of consumption of young plants. Alkaloids are not lost upon drying. For many lupines, the time and degree of seeding varies year to year. Most losses occur under conditions in which animals consume large amounts of pods in a brief period, such an area, trailing animals through an area where the grass is covered by snow but the lupine is not or when feeding podded lupine hay, which apparently palatable.