"Livestock's Long Shadow"

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Do curso por University of Pennsylvania

Feeding the World

60 classificações

University of Pennsylvania

Feeding the World

60 classificações

This course will explore the concepts driving current food production science (population growth, urbanization, emerging affluence, resource constraints, and underlying biological limits) with the main focus on livestock production. Each of the major food animal species (dairy, swine, beef, and poultry) will be covered in terms of their universal life cycles, constraints to production and emerging societal issues. Throughout the course, we will tackle some difficult and important questions: What are the major health benefits and potential concerns regarding the production and consumption of animal products? How does animal production affect the efficient use of resources and impact our environment? Can cost of production be reduced to meet growing demand for animal products around the globe while maintaining health and safety for both animals and consumers? What are the different types of animal food production systems? Myths and misconceptions surrounding the animal food systems will be discussed. We’ll also look closely at some of the global issues, problems, and challenges in these food systems which scientists, farmers, and veterinarians, are attempting to solve through collaboration. Lectures will be delivered by several experts from the University of Pennsylvania, School of Veterinary Medicine who are intimately involved in the study and advancement of animal production systems. The course is geared towards learners who seek a greater understanding of animal food systems as well as those who might have never visited an animal farm, but have a desire to learn more about where some of our food comes from and issues surrounding sustainability.

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Issues Surrounding Animal Production

This module begins to explore the fundamental principles of animal production operations and the issues surrounding animal production. We will look at the efficiency and environmental impact of the food system as well as animal welfare concerns. Finally, we will discuss the importance of water as an essential resource for the food production system.

"Livestock's Long Shadow"5:41

"Long Shadow - Concerns"8:58

Introduction to Animal Welfare7:02

Land Use: Animal Feeding Systems and Major Food/Feed Crops10:54

Conheça os instrutores

Dr. David Galligan
Professor of Animal Health Economics
School of Veterinary Medicine
James Ferguson
Professor of Nutrition
School of Veterinary Medicine

[MUSIC]

Let's talk about Livestock's Long Shadow,

its environmental impact on our feeding systems of animals.

This comes from the title of a publication by Henning Steinfeld from

the Food Agricultural Organization in 2006.

And it looked at some of the environmental degradations from livestock systems.

Well there are some positives with livestock,

they produce a high quality protein in a concentrated form.

Animal manure is very important as a source of nutrients,

especially carbon, nitrogen, phosphorous, potassium for plant growth.

Livestock are also an important sources of income for about 1.3

billion people in the world received their livelihood by livestock production.

And livestock contribute to about 40% of the global gross domestic production from

agriculture.

So they have a very significant positive benefit throughout the world.

However, the negatives.

Our livestock systems may have negative effects on land, on air, and on water.

Eutrophication of water systems from excessive runoff of manure nutrients,

especially nitrogen and phosphorus, can cause eutrophication.

Green house gas emissions, especially from enteric emissions of methane

from herbivores, can create green house gases.

And then, nitrous oxide, from manure application of soils,

also contributes to greenhouse gases.

And then, livestock manure also may contain potential pathogens,

bacteria that are harmful.

And we know, we've heard of all sorts of food outbreaks from e coli,

salmonella, corynebacterium.

If we look at what's been happening though, with global livestock production,

we can see from 1960, there's been a tremendous increase in the number of

poultry, the number of sheep and goats, the number of cattle, the number of pigs.

And even the number of rabbits that are grown for meat production and

milk production throughout the world.

And so, the livestock industry has greatly increased over the last 50 years.

And what happens when we feed livestock is,

we have our food inputs that go into our animals.

And about 10 to 40% of what we feed them is indigestible.

That's going to end up in feces.

What gets digested is utilized to make products like meat and milk.

However, that happens with efficiency of anywhere from 25 to 40%.

And so, the inefficient use of absorbed material, absorbed nutrients for

producing meat and milk, also ends up in urine, gets excreted as urinary waste,

and that also ends up in the environment, or in an animal manure.

So if we look at what comprises animal manure, we have feces that are composed of

indigestible feed material, endogenous secretions from the gastrointestinal

tract, mucus, sloughed cells, enzymes that are secreted.

And then we also have bacterial debris.

We have bacteria in the large intestine that are excreted with the feces.

We have bacteria and ruminants in herbivores that come from the foregut.

And secondly, we have urine, that really gets rid of nitrogenous wastes.

Things like urea, ammonia, creatinine, and allantoin,

allantoin from digestive metabolism of nucleic acids.

And also, urine secretes a lot of cations and anions, sodium, potassium, calcium,

magnesium, and hydrogen ions, chlorides, phosphates, sulfates, carbonates.

And this is to maintain osmotic balance and acid-base balance within the animal.

In addition, in manure we have bedding, and also, we have wastewater coming from,

maybe, the milking parlor, or cleaning barns and other systems.

That manure gets stored, it may go directly on pasture,

if animals are grazing.

It may be stored in stacks.

It may be stored in lagoons and pits.

And eventually, it gets out, placed on soils,

and we can have losses into the environment.

Amonia from urinary excretion into the atmosphere from the barn,

from the animals, we also have methane and nitrous oxide.

We also have, when the manure goes out to fields, possibilities of nitrates and

phosphates in the water systems.

When we look at these total animal numbers, how much manure do they produce?

So they produce a gross estimate with about 2,630,000

tons annually of animal manure, that'd be dry matter in the world.

That contains 43.5 million tons of nitrogen,

19.2 million tons of phosphorus and

37.3 million tons of potassium.

So how much land can that manure go on?

Well, if we based it on 150 kilograms of nitrogen per hectare,

it could go out to almost 290 million hectares of about

1.4 million hectares or billion hectares of arable land.

In addition, there's agricultural land, like pastures and areas that are grazed

that are about 4.8 billion acres available.

And so, we have plenty of land to utilize that nitrogen,

the problem is, using it appropriately.

In addition,

there's about 80 [COUGH] million tons of fertilizer nitrogen that's used each year.

Livestock produce a lot of manure.

And we have concerns with the impact that manure can have on the environment,

both land, air and water.

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