Stanton PhD Thesis final_docx - Atrium - University of Guelph

CHAPTER 1: LITERATURE REVIEW
1.1 INTRODUCTION
Bovine respiratory disease complex (BRD) and neonatal calf diarrhea complex are the
two most commonly diagnosed diseases in pre-weaned and weaned dairy calves, and account for
between 60-80% of dairy heifer mortality in the United States (USDA, 2010b). These diseases
are very important due to the impact that they have on animal welfare and productivity.
Animal welfare issues can be categorized into three main ethical concerns (Fraser et al.,
1997). The first category is functional, which are concerns focused on deviations from normal
physiologic function, such as poor health or growth. The second category stems from a feelings
based approach to animal welfare, which are concerns focused on avoiding prolonged or intense
pain, discomfort or other negative emotional states, as well as allowing for positive emotional
states. The final ethical category is based on the natural view, which focuses on the natural
behaviors of animals based on their evolutionary adaptations and capabilities. Although
described separately, in practice many of the current animal welfare concerns negatively impact
animals under all of the ethical areas. An example of this would be bovine respiratory disease
(BRD), which decreases the health and growth of animals. BRD also is likely to be associated
with shortness of breath, or ataxia, which is considered to be a negative affective state in many
species (Mellor & Stafford, 2004). By considering all three ethical concerns in conjunction with
the potential economic impact for the producer, management systems can be improved for the
benefit of both producers and animals.
The failure of the dairy industry to address animal welfare concerns can lead to
legislative changes, which can force change. An example of this is the European Union directive
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