Page 17 - The Welfare of Cattle

xvi IntroduCtIon to the WhIte PaPers

first lactation if a dairy cow, or ready to go to a feedlot to finish their growth and fatten up prior to
slaughter for beef cattle.
The driving factor toward intensification has to do with shrinking profit margins based on low
prices to the producer for their products and higher costs of inputs. Increasing efficiency is often as
simple as increasing the number of animals per unit of land. In this setting, nutrients are imported,
while milk and meat are exported and the wastes remain on the farm. This is a parallel to people
moving from farms to cities so more wastes are managed in a smaller area.
Genetic and management improvements including nutritional support have resulted in fewer
animals making more milk and/or meat. Today’s dairy cattle, for example, captures 35% of the
consumed protein as meat or milk where a few decades ago that figure was ~20%. Beef cattle have
also improved and compared to 1977 and now excrete 12% less nitrogen and 10% less phosphorus.
Comparing 1977 and 2007, beef produced the same amount of meat with 30% fewer cattle, 19% less
feed, 12% less water and 33% less land, and had a 16% decrease in their carbon footprint.
Costs of reducing environmental impacts are largely borne by the producer. Consumers need to
share in these costs, including assuming some of the costs of production and by decreasing wastage
of food produced. Estimates are about 30% of food produced is wasted today, and that represents the
largest single component of the life cycle costs associated with beef and dairy products.

Microbial Pathogens in Extensive and Intensive Animal Agriculture Systems

Pramod Pandey, MS, PhD and E. R. Atwill, DVM, MPVM, PhD
School of Veterinary Medicine
University of California, Davis, CA

Professor Pandey is an agricultural engineer and Professor Atwill is an epidemiologist who
works on understanding and managing microbial threats to the environment and food. Dr. Atwill
is the director of the Western Institute of Food Safety and Security.
Microbes dominate the life forms in our world, and include viruses, bacteria, protozoa, and
fungi. They make critical contributions to the health of soils, plants, animals, and humans. They
also can threaten the health of plants and animals. Sewage waste from animals and people may
contain pathogenic microbes that can cause disease in susceptible species.
Today’s animal agriculture systems in the USA produce more than a billion tons of manure.
How manure is handled on-farm can influence the types and number of microbes found in it.
Confinement operations, so called intensive systems, are able to implement methods to
collect and treat manure that lower or eliminate disease-causing microbes. Composting, anaero-
bic digesters, and liquid/solid separation lower both the number of microbes and the number of
pathogens.
Extensive systems such as pastures tend to leave the manure where it falls and rely on Mother
Nature (via sunlight, temperature, and time) to lower the number or eliminate pathogens. About 8%
of manure from beef cattle’s extensive systems is recoverable for treatment or transportation com-
pared to ~75% of dairy cattle’s intensive system.
Animal manure is seen as a commodity with some economic value especially to improve crop
production, but untreated manure may be a threat to human and animal health. Limiting envi-
ronmental exposure to these organisms is a worthy goal. Microbes are not very mobile, relying
instead on hitching a ride on something else that’s moving to get from one point to another. The
leading vehicle for spread is water runoff and this can be a problem in both intensive and extensive
production systems.
Intensive systems produce more food per unit of resource input (water, land, feed) and a lower
level of environmental contamination per unit of food produced. About 29% of the world is land.