ABSTRACT Lupine species may contain teratogenic alkaloids that cause birth defects called crooked calf syndrome. If pregnant cows ingest toxic lupine between d 40 and 100 of gestation, fetal movement is impaired and irreversible skeletal defects occur. To prevent ingestion of this toxic forb during the critical period of gestation, there is a need to determine the time and conditions in which cattle graze velvet lupine (Lupinus leucophyllus Dougl. ex Lindl.). Intensive grazing trials were conducted to evaluate cattle consumption of lupine in its stages of phenological development through the growing season, in relation to increasing grazing pressure in eastern Washington. Ten Hereford cows and a bull grazed velvet lupine-infested rangeland in 3 grazing pressure trials each year. Pastures were fenced to limit forage availability to the amount required for 6-d trials in 2007 and 10-d trials in 2008. Diets were estimated by bite count. Linear and quadratic regression was used to describe the relationship between forage allowance (the reciprocal of grazing pressure) and lupine consumption. In May, cattle preferred green cheatgrass (Bromus tectorum L.) and immature forbs at the beginning of the trial and did not graze lupine until all other forage was depleted. There was a negative linear relationship between declining forage allowance and increasing lupine consumption (r 2 = 0.91 and 0.78 for 2007 and 2008, respectively). In June, cheatgrass was dry and cattle preferred forbs that were flowering. As availability of palatable forbs declined, cows started eating lupine, and this declined as its availability declined. Quadratic regressions were not strong (r 2 = 0.10 and 0.53 for 2007 and 2008, respectively). In July when annual forbs matured and became fibrous and unpalatable, cattle ate lupine at the beginning of the trial and reverted to dry cheatgrass as lupine became limited. There was a quadratic regression in 2007 (r 2 = 0.37) and a positive linear regression in 2008 (r 2 = 0.69). We conclude that lupine is not palatable early in the growing season in May and early June, but cattle can be forced to graze it as availability of green cheatgrass and other forbs declines. Intensive grazing systems that force cattle to use all forage may enhance the risk of crooked calf disease by forcing cattle to graze lupine throughout the grazing season.