Weed of the Month

Lupine

            In the Western United States, all livestock are susceptible to lupine poisoning, but sheep are primarily affected. Losses may be especially heavy when hungry sheep are trailed through lupine ranges in late summer.

 When and where is it found?

            Lupine grows on sagebrush ranges and on grassy slopes. It is found in areas up to 11,000 feet high.  The poisonous species in Colorado are perennials. They emerge early in the spring, flower in June, and lose seeds in July or August. During years with a wet spring, lupine populations explode and may be especially troublesome.

 What does it look like?

            Lupine are bushy plants that grow in clumps. The weed reach heights of 1-2 feet tall. Their leaves are palm-like and composed of several leaflets, which radiate from a central point. The pods are usually hairy and the flowers grow in clusters on the stalk. Although blue is the most common color, flowers may also be white, pink, yellow, or blue and white. 

 How does it affect livestock?

            Lupine is dangerous from the time it starts to grow in the spring until it dries up in the fall. Younger plants are more toxic than older plants; however, plants in the seed stage in late summer are especially dangerous because of the high toxin content of the seeds. Lupine is also more palatable than the dried pasture grasses in the late summer.

            The amount of lupine that will kill an animal varies with the lupine species and the stage of plant growth. A sheep that is getting good forage may not be affected by occasionally eating a small amount of lupine ( about 1/8 to ¼ lb.), but a sheep is usually poisoned if it eats 1/8 to ¼ lb. of lupine daily for 3 to 4 days.

            Cattle may be poisoned by eating 1 to 1 ½ lbs. of lupine without other forage. Smaller amounts are poisonous if cattle eat the weed daily for 3 to 7 days. If cows consume the plant between days 40 and 70 of gestation, their calves will often suffer from crooked calf disease. These calves are born with cleft palates, crooked legs and distorted /malformed spines. Epidemic outbreaks of such birth defects can have high morbidity resulting in enormous animal and economic losses.  

 What are the Symptoms of an infected animal?

·        Nervousness

·        Excessive salivation, frothing at the mouth

·        Depression

·        Lethargy

·        Difficulty Breathing

·        Leg muscle twitches, loss of all muscular control

·        Convulsions

·        Coma

·        Death

What if my animal has been poisoned?

            There is no antidote for lupine poisoning. Allow affected livestock to rest quietly, especially if they are unfamiliar with human contact. Handling, trailering, or other stress on animals after they have been grazing lupine will make the signs worse and can increase losses.  

How can I reduce my losses?

            Losses can be reduced by keeping hungry animals away from lupine patches in their early growth stage and in late summer when the plant is in the highly toxic seed stage. Animals should always be kept away from dense plant stands. Supplemental feeding is beneficial, especially when animals are trailed through lupine ranges.

            Do not allow hungry animals to have access to lupine, particularly when it’s the seed stage, if other forage is not available.  If lupines are prevalent in the pasture, become familiar with the particular species present, since toxicities vary. Do not handle, process, or ship animals that are heavily grazing lupine since this type of stress will increase the number of animals that will become sick and/or die. Livestock can graze lupine without incident as long as excessive ingestion is avoided and animals are not handled or trailered while on lupine pastures ( and if the animals are not pregnant) In cattle, to avoid birth defects, do not allow grazing between days 40 and 70 of gestation.

            In addition, since the toxins in lupine remain after the plants have dried, hay containing the weed is unsafe for livestock.