Chap 6 continued Chap 7 Assimilation Efficiency A = E assimilated / E total GD Goodman-Lowe, JR Carpente, S. Atkinson (1999) Assimilation efficiency of prey in the Hawaiian monk seal (Monachus schauinslandi) Can. J. Zool. 77: 653660 Variability due to differences in diet (quality) within a species Rumen e Reticulum Omasum Abomasum Rumen Bacterial fermentation of cellulose Reticulum Compression and regurgitation of plant material Omasum Water re-absorption and further filtering Abomasum Digestive fluids added to chyme Rabbits cecal Non-cecal pellet So, with all these adaptations Are cows any good at assimilating energy from food? A for several species Elephant 1.5% Cow 11% Pig 13% Grasshopper 37% Tent catepillar 57% Applied Efficiencies or autotroph herb carn Big impact by eating lower on the food chain Land needed to feed cow / mo: range = 12.3 acres productive area = 1 Water needed for beef = 2500gal/lb No. of animal species threatened with extinction on rangelands = 90 Excrement by total US human population: 12,000 lb/sec Excrement by US livestock: 250,000 lb/sec (including 25 pounds of manure per cow per day) Chap 7 Concentrate: Introduction Carbon Water Nitrogen Microbes Figure 7.2 Figure 7.4 Figure 7.5