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Blog: Why beef and dairy production is being unfairly criticized in the global food sustainability conversation
10 January 2020
Production has far less of an impact on human-grade food
production than its critics make out, with almost 90% of feed for
beef production made up of elements inedible to humans
Cattle, sheep and other ruminants - defined as mammals that
ferment plant-based food in stomachs with four compartments - serve
a valuable role in sustainable agricultural systems. They are
particularly useful in converting vast renewable resources from
rangeland, pasture, and crop residues or other by-products into
food edible for humans.
However, a criticism that has been directed towards ruminant
production - such as cattle reared for human consumption - is that
they consume food edible for humans and graze on pastures that
could be used for crop production. Furthermore, livestock are often
portrayed as poor converters of feed ingredients into human food
products.
In reality, a large proportion of most ruminant diets are
various forages such as hay, silage or fresh grass. These materials
are totally inedible for humans and they are produced in large
volumes. Ruminants, both beef cattle and dairy cows, have
historically also been the main consumers of by-products from the
human food and biofuels industries supporting a waste-disposal
problem and contributing to the circular economy.
What feed goes into beef production?
In an extensive Life Cycle Assessment (LCA) of beef production
in the USA the total volume of food consumed by cattle to produce 1
kg of carcass weight of beef was about 22 kg (Rotz et al., 2019).
The feed comprised about 82% forage, 11% grain and 7% by products
and waste products.
It is important to note that only 12% of the total feed consumed
to produce 1 kg of beef was from grain concentrate, which might
have had a potential availability for direct human consumption. The
major constituents of the feed were forage at 82% and by-products
or waste products at 6.7%, all totally unsuitable for human
consumption. Therefore, about 2.6 kg of potentially human edible
grain was used to produce 1 kg of beef. The nutritional value and
desirability for humans of 1 kg of beef is far greater than 2.6 kg
of a grain concentrate. This is a very powerful demonstration of
the value of ruminants to convert large amounts of forages and
other materials, totally inedible for humans, into high-value human
food products.
Considering nutritional value is important
A problem with much of the research on LCA from agriculture is
that it does not incorporate the nutritional value of the foods but
rather focuses on mass of product produced. However, it is
important to be able to capture the actual nutritional value of
food products of animal origin for humans in order to fully assess
the efficiency of animal production. It is evident that LCA can be
used to generate a wide range of values relating to global warming
potential and greenhouse gas emissions. Nevertheless, comparing
environmental performances of products on a mass basis may not be
appropriate but the nutrient composition of the product must also
be considered. It is also clear that foods from ruminants with a
high nutritional value can be produced that do not contribute
excessively to environmental problems.
Meat, especially beef, is a good source of protein and of
micronutrients such as iron, selenium, vitamins A, B12 and folic
acid. Iron has a high bioavailability when derived from meat. Milk
and other dairy foods, particularly cheese, provide important
nutrients such as calcium, magnesium, protein and fat.
Reducing environmental impact
Ruminants have two major adverse impacts upon the environment.
They produce various greenhouses gases and release nitrogen and
phosphorus into the environment which can impact upon air quality,
global warming, and soil and water pollution. These problems are
recognised and are being addressed. Reducing crude protein levels
to around 140 g/kg DM in dairy cow diets increases the efficiency
of nitrogen capture and reduces nitrogen excretion to the
environment. Similarly, reducing over-feeding of phosphorus is a
powerful tool to decrease the phosphorus content of manure.
A fundamental improvement in sustainability can be achieved by
improving ruminant production. Higher output of milk and meat from
ruminants reduces the number of animals required. This in turn
reduces feed requirements and the consequent environmental
pollution. There is considerable scope to improve dairy cow
efficiency in the EU which will help in sustainability.
A major strength in the argument for the sustainability of
ruminant production is the fact that ruminants eat substantial
quantities of forages and increasing quality or digestibility of
forages will increase production efficiency. There has been a large
amount of research directed to processing various crop residues to
improve their digestibility for ruminants. Various chemicals such
as sodium hydroxide, potassium hydroxide, calcium hydroxide,
ammonia and urea are the most important and effective in improving
the digestibility and nutritive value of straws.
Methane is a major greenhouse gas emitted by ruminants and
nowadays there is considerable research efforts devoted to reducing
these methane emissions. Phytochemicals, vaccines, dietary lipids,
electron acceptors such as nitrate and ionophores have all been
studied as part of a methane reduction strategy. The compound.
3-nitrooxypropanol is of interest in methane reduction. Good manure
management and anaerobic digestion also contribute to reducing the
environmental impact of ruminant production.
Future directions are to improve the nutritional quality of meat
and milk, to manage ruminant health without antibiotics and to
develop the use of new and novel feed ingredients such as wood,
microalgae, seaweeds and insects.
Ruminants have served and will continue to serve a valuable role
in sustainable agricultural systems.
To find out more the benefits and impacts, mitigation
strategies and future direction of ruminant production in
agriculture download a sample of our latest 60-page special report
titled The Role of Ruminants in
Sustainable Agriculture 2020, authored by Dr Clifford
Adams.