Page 3 - Livestock and Companion Animals

2–1. A scientist is using a type of x-ray to measure the body composition
of a live pig that has been anesthetized. (The x-ray is DEXA, or dual-energy
x-ray absorptiometry. This does not injure the pig.) (Courtesy, Agricultural
Research Service, USDA)

NIMALS are complex creatures. Most have the same basic systems
A and needs for life to occur. Cells, tissues, and organs of an animal
serve important roles. Organ systems carry out life processes. While
much has been learned about animals, there is a lot more to learn.
Just as animals have many similarities there are differences. The dif-
ferences are greater between species that are not so closely related. For
example, birds have greater differences with livestock than with other
birds. A fish species is more like other fish than it is like dogs or guinea
pigs. Unique life processes must occur if members of a species are to
thrive.
People are better producers, care-givers, and friends of animals if
they know animal biology. Knowledge helps people understand why
animals respond as they do and how to respond to their. Learning the
major internal and external parts and functions of animals is a good
place to begin. This chapter provides a good starting point.

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