Lecture 21: Livestock and Meat

what are the contradictory claims surrounding meat and livestock?

some claim meat is environmentally damaging, while others believe rotating livestock can be beneficial for grazing and soil

despite manure being beneficial for soil fertility, why is the manure produced in feedlots worrisome?

it is in high concentrations and therefore is difficult to get rid of- can lead to pollution and runoff

nearly all beef cattle spend the first months of their lives where? where do they end their lives?

grasslands and range lands; feedlots

what is the state of the arguments surrounding meat and livestock?

widening gap between the arguments

where does cattle production happen?

various types of land, climate, and social settings (everywhere)

pasture area

how much of the land is open for grazing

what are the three categories of livestock production?

grassland based: more than 90% of feed from rangelands

mixed: more than 10% of the feed is from crop by-products

feedlots: 70-95% of feed is from purchased grain

what system of livestock production is the dominant system in the world?

mixed system

in which system of livestock production has output growth increased the most?

feedlots due to the efficiency of grain-fed production processes.

what is the economically competitive way to produce meat?

factory farming/feedlots

what are the impacts of grassland-based livestock production?

impacts per unit product are high but the overall amount of impact is low

livestock serve multiple roles and are critical to well-being

what are the impacts of mixed livestock production?

integrated with crop production but inefficient

aggregate impacts are high

what are the impacts of feedlot livestock production?

highly efficient; can afford to invest to improve environmental performance (they are lucrative)

industrial livestock is simultaneously a __________, a _______, and a _________ for a range of major problems in food systems

symptom, cause, solution

livestock is ___% of agricultural GDP

40

__% of arable land is used for livestock feedcrops

33

the livestock industry employs ___ billion people, and supports ___ billion livelihoods

1.3, 1

__% of Earth’s land is used for grazing

26

global livestock contributes to __% of green house gas emissions

8

livestock production is a major driver of

deforestation

what are the global tends of meat consumption?

rising overall and projected to increase by 62-144% by 2050

what is happening to the price of meat?

it is decreasing despite increasing demand; supply/production of meat is outpacing demand

what are the dietary benefits of expansion of meat consumption?

malnutrition has drastically declined, especially amongst children

Bennet’s Law

as people become wealthier, their diets change from being largely based on starchy staples to diets that incorporate increasing amounts of refined grains, fruits, vegetables, meat, and dairy

what is the economic significance of livestock

40% of global agricultural output by price

important livelihood source, especially in some countries

important source of protein and some nutrients, especially in low-income settings

what are the health effects of meat consumption?

red meat and processed meats increase risk of colorectal cancer in high-income populations

processed meat consumption correlates with risk for several other diseases, but evidence is not conclusive

why are robust studies for meat consumption rare?

study would need to be carried out over a long period of time

need to have a control groups that doesn’t eat meat

correlation between various diseases- need to disaggregate various lifestyle factors (confounding variables)

how significant are the health effects of processed meat (use colorectal cancer as an example)?

eating processed meat increases colorectal cancer by 50%, but it only increases risk from 1% to 1.5%

from a public health perspective meat is potential a source of _______ _____ and _____ _______

foodborne illness; antibiotic resistance

what are the environmental impacts of meat production?

high water use for growing crops for livestock

manure and nutrients are a major risk and impacts are concentrated; potential benefits when diffuse

biodiversity: deforestation

what are the greenhouse gas emissions from livestock?

9% of anthropogenic CO2 emissions

37% of methane emissions

65% of nitrous oxide emissions

64% of ammonia emissions

how does livestock production affect climate change (positively)?

livestock production by rotational high-impact grazing can help plant growth, greater infiltration of water into the soil, the soil can store more carbon

however, estimated benefits are localized

there is global _______ in emissions intensities of ruminants is greater than most other foods

variability

livestock in the developed world has _______ emissions; why?

reduced; high quality forages and feeds, improved livestock breeds, and high reproduction in growth rates

compare beef cattle between Sub-Saharan Africa (pastoralism) and US (ranching)?

US cattle are raised to weigh more and live shorter lives while Sub-Saharan African cattle are often smaller, live longer, and are raised in traditional pastoral systems with lower productivity but greater adaptability to local conditions

from a GHG point of view, if you wanted to produce more meat with less environmental impacts, what system would you want to employ?

feedlots

for CO2 ________ emissions matter more, for methane the ______ of emissions matter more

cumulative, rate

what does cumulative emissions matter more for CO2?

atmospheric lifetime of CO2 is 100-200 years (for a long time); need to concern ourselves with concentration of CO2?

why does rate of emission matter more for methane?

atmospheric lifetime of methane is 8-10 years; because methane is short-lived if we can bring down the rate of emission it will have a fairly immediate effect

why have US methane emissions from cattle production come down?

the size of cattle have increased but the beef cattle population has decreased overall

the transition of beef production is transitioning from _____ to ____ ______

grazing, mixed systems

what would happen if we could remove livestock production from US agriculture and rely on plant-based diets for nutrients?

it is possible, but it can be a challenge for an entire population

livestock convert energy-dense dense micronutrient-poor crops into more micro-nutrient dense

there would be a substantial increase in land needed to grow crops

people would need to eat more food than they do to get the nutrients they get from meat

what would happen to GHG if we eliminated animals?

CO2 emissions would decline but plant growth also emits GHG and the net effects would depend on land-use changes

how is industrial livestock production a solution for some problems?

produces meat in an efficient way (environmentally)

reduces malnutrition

how is industrial livestock production a symptom?

symptom of a food system that pushes for efficiency

makes use of technologies to remain competitive

how is industrial livestock production a cause of various problems?

manure management problems

antibiotic resistance