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Forage Quality of selected Warm−Season Weed Species

Bosworth, S. C., Hoveland, C. S., Buchanan, G. A., Anthony, W. B.
Agronomy journal 1980 v.72 no.6 pp. 1050-1054
Cynodon dactylon, Pennisetum glaucum, calcium, crude protein, dry matter digestibility, flowering, forbs, fruiting, grass weeds, hay, in vitro digestibility, magnesium, metabolic diseases, nutrient content, nutritional adequacy, nutritive value, pastures, phosphorus, pure stands, ruminants, silage, vegetative growth, warm season, warm season grasses
Although weeds are a common component of pasture, hay, and silage, limited information is available on forage quality of warm−season weeds. Forage quality of 17 warm−season weeds and two cultivated forage species seeded in pure stands was determined at vegetative, flowering, and fruiting development stages to ascertain nutritive value for ruminants. At the vegetative stage, 16 of the 17 weed species had greater in vitro dry matter digestibility (IVDMD) than ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] or ‘Millex 23’ pearlmillet [Pennisetum typhoides (Burm) Staph & C. E. Hubb.]. The majority of forbs had crude protein (CP) concentrations of 20% or more at the vegetative stage. Generally, IVDMD declined as plants matured. Some grass weeds were lower in CP and comparable to pearlmillet and bermudagrass. Crude protein concentrations generally declined as plants matured. All weed and forage species had nutritionally adequate amounts of Ca, Mg, and K. Phosphorus levels were sub−optimum for high producing ruminants in seven forbs and had high Ca:P ratios which could cause metabolic disorders in ruminants if used as a sole feed source. Many of these warm−season weed species at the vegetative stage can offer ruminants a nutrient level comparable to that of cultivated grasses such as Coastal bermudagrass and pearlmillet.