Chap 6 continued Chap 7

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Chap 6 continued Chap 7
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Assimilation Efficiency

• A Eassimilated / Etotal

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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
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Rumen
e
Omasum
Abomasum
Reticulum
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Rumen

• Bacterial fermentation of cellulose

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Reticulum

• Compression and regurgitation of plant material

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Omasum

• Water re-absorption and further filtering

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Abomasum

• Digestive fluids added to chyme

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Rabbits
Non-cecal pellet
cecal
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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

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Applied Efficiencies
or
carn
herb
autotroph
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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)
Big impact by eating lower on the food chain
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Chap 7

• Concentrate
• Introduction
• Carbon
• Water
• Nitrogen
• Microbes

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Figure 7.2
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Figure 7.4
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Figure 7.5