Is Livestock Production Heading Over The Cliff and Doomed? J M Wilkinson

How much feed does it take to produce a kg of meat and milk?

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

Feed Conversion Ratios *Whole milk, bone-in carcase fresh weight or egg + shell Wilkinson, 2011

Human-Edible Feed Conversion Ratios

Human-Edible Feed Protein Conversion Wilkinson, 2011

Human-Edible Feed Protein Conversion Wilkinson, 2011

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

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?

Diet Carbon Footprint per kg Product

Non-Grass Feed Carbon

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

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?

How much arable land is required to produce human-edible feed for livestock?

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

Thank you!