cow’s environment and therapeutic management of udder health during the dry
period. A third condition that can cause high levels of morbidity and mortality is
bacterial respiratory disease. Pneumonia in young livestock is often exacerbated by
stressful transportation and co-mingling of animals from different herds. The
welfare consequences and production losses can be significant. Antimicrobial
treatment of pneumonic animals and, when appropriate, of in-contact animals
living in the same air-space is an integral part of whole-herd respiratory disease
management. The role of the veterinary profession is to also ensure that principles
of population medicine are understood and adhered to by pet owners. The increase
in pet ownership and the importance of the human–animal bond in modern deve-
loped societies give rise to zoonotic risks, which require vigilance and intervention.
Regular internal parasite control in dogs and cats, particularly in endemic areas,
contributes to animal welfare and minimises public health hazards.
KeywordsBovine respiratory diseaseGroup therapyHelminthsMastitis
Public healthSwine respiratory disease
1 Introduction
Animal welfare, herd productivity and public health are the key drivers for a
population-based approach to treatment and prevention of animal diseases. Veteri-
nary practitioners, livestock producers, research scientists, pet owners and policy
makers have roles to play in understanding the dynamics of disease transmission and
in designing and executing group-oriented interventions to control diseases. Whilst
immunisation plays a major role in the prevention of viral epidemics, minimising the
impact of parasitic (usually helminth) infections and many bacterial and mycoplas-
mal diseases on animal production and welfare remains largely dependent on the
rational use of anti-infective agents. Viral diseases are beyond the scope of this
chapter; suffice it to mention that the control of their spread involves a combination
of restricting animal movement, strict biosecurity measures, culling and vaccination.
This chapter focusses on the use of chemotherapeutic agents, at herd, flock and
population levels, to control and prevent non-viral infectious diseases. Three areas
of therapy will be considered: helminthiases in livestock and companion animals,
mastitis in dairy cattle and bacterial respiratory disease in cattle and swine.
2 Helminth Control
2.1 Helminth Parasites of Ruminants
In the developed world, economic losses related to helminth (worm) infections of
livestock are principally the result of treatment and prevention costs. For example,
114 H. Benchaoui