11:067:330 Lecture 24: Grazing Animals (Cpt 20 + 22)
21 Jul 2017
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Document Summary
Exist wholly or partly on grasslands / naturally growing pastures: consist of true grasses and other forages like legumes. Cellulose is most abundant organic substance on earth consumed by grazing animals. Converted to milk, meat, and fiber: cellulose unusable to us without these animals. In us and europe: most livestock produced using intensive systems. But worldwide, most exist on pasture cheap feed = economically efficient. Grazing animals don"t compete with us for food (we don"t eat pasture and often can"t grow other things there) Pasture-raised ruminants produce milk, meat, and fiber using land not suitable for human food. Natural rangelands occupy ~30% of earth"s land surface. North american prairies, asian steppes, south american pampas, african veld. Managed pastures = ~20% of earth"s land surface. Managed pastures areas we work to keep as pasture (prevent tree growth and use irrigation for grass) Often semiarid areas directly adjacent to natural rangeland. Water supply = a strong predictor of plant production.
