Page 3 - Livestock and Companion Animals
P. 3

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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