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Is Livestock Production Heading Over The Cliff and Doomed? J M Wilkinson
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How much feed does it take to produce a kg of meat and milk?
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Human-Edible Feed in Typical Diets Human-edible feed (% of total diet dry matter) Grass-fed lamb5 Grass-fed cow/calf beef7 Grass-fed dairy beef12 Cereal beef45 Pigmeat64 Eggs65 Poultry meat75
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Feed Conversion Ratios *Whole milk, bone-in carcase fresh weight or egg + shell Wilkinson, 2011
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Human-Edible Feed Conversion Ratios
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Human-Edible Feed Protein Conversion Wilkinson, 2011
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Human-Edible Feed Protein Conversion Wilkinson, 2011
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Conclusions 1.Ruminants have a special ecological niche as efficient fibre digesters 2.Ruminants are less efficient converters of total feed compared to pigs and poultry 3.BUT most of ruminant diet is not human-edible 4.Grass-fed cattle and sheep are as efficient as pigs and poultry at converting human-edible feeds into milk and meat
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Greenhouse Gas Emissions Livestock are much less efficient than crops Ruminants account for 80% of global livestock greenhouse gas emissions Methane = c. 50% of livestock emissions Animal feed production and processing are significant components of livestock emissions Can we assume zero carbon footprint for grassland?
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Diet Carbon Footprint per kg Product
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Non-Grass Feed Carbon
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Conclusion If grass is credited with a zero carbon footprint, cattle and sheep are as efficient at converting feed carbon into animal product as pigs and poultry
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Arable Land Use 33% of the world’s cereal harvest is used as feed for livestock Arable land is in limited supply Livestock diets containing human-edible feeds (e.g. wheat, soyabeans) compete for land that can grow food for the human population How much arable land is required to produce the human-edible feeds in diets for different livestock production systems?
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How much arable land is required to produce human-edible feed for livestock?
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Conclusion It requires two to four times as much arable land to grow the human- edible feeds to produce a tonne of animal product from pigs and poultry compared to cattle and sheep
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Thank you!
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