Research Note Effects of Experience and Lactation on Lupine Consumption by Cattle

Lupines (Lupinus spp.) are widespread range plants that are often toxic to livestock. Some reports suggest that naı̈ve, younger animals might consume more lupine than more experienced, older cattle. Further, lactational stress might alter forage selection, and lactating cows might eat more lupine than nonlactating cows. Thus, the objectives of these trials were to examine the influence of experience and lactation on lupine intake. Both study areas were near Ritzville, Washington, on rangeland dominated by cheatgrass or downy brome (Bromus tectorum L.), with abundant velvet lupine (Lupinus leucophyllus Dougl.). During the first trial, six naı̈ve and six experienced Hereford cows were grazed together for 25 d during summer. There was no difference (P. 0.5) in consumption of lupine by naı̈ve and experienced cows. Consumption peaked at 10%–14% of daily bites. During the second trial, six lactating and six nonlactating cows grazed a lupine-infested pasture for 18 d. There was no difference (P. 0.6) in consumption between lactating and dry cows. Lupine consumption gradually increased and peaked at 10%–15% of the diets. Our results suggest that experience and lactation status are probably minor considerations in livestock management schemes to reduce losses to lupine.