Objectives and principles of farm animal practice
The primary objective of this article is to provide the veterinary
student and the practitioner with the knowledge and information necessary to 'provide animal health management for farm animals. This is a commentary on the objectives and principles of veterinary practice related to the animal health and production of cattle, sheep, goats, pigs and horses.
FOOD-PRODUCING ANIMALS
Food-producing-animal veterinary practice provides service
primarily to the owners of the meat-, milk- and fiber-producing
animals such as dairy and beef cattle, pigs, sheep and goats.
Veterinarians also provide service to owners of captive ungulates, such as red deer, elk and bison, that are being raised under farm conditions for the production of meat and byproducts such as hides. While some commercially processed horsemeat is consumed by humans, the market is small compared to beef and pork, and horses are not usually included in discussions about food-producing animal veterinary practice. Poultry, fish and rabbits are also important sources of human food but are not the subject of this book.
For the past several decades, the major activity in foodproducing-animal practice, and a major source of income for veterinarians, was the provision of emergency veterinary
service to the owners of herds or flocks in which a single animal
was affected with one of the common diseases. Occasionally,
outbreaks of disease affecting several animals occurred. In
addition, routine elective veterinary services such as castration,
vaccination, dehorning, deworming, the testing for diseases such as brucellosis and tuberculosis and the dispenSing of veterinary drugs, pharmaceuticals and biologicals accounted for a significant source of revenue for the veterinarian. Since about the early 1970s, there has been a shift from emphasis and dependence on emergency veterinary medicine and routine procedures to more attention being paid by the veterinarian and the producer to planned animal health and production management using the whole-farm approach. Livestock producers are now much more knowledgeable about animal agriculture and are concerned about the cost-effectiveness and the scientific basis of the recommendations made by veterinarians and agricultural advisors. More and more producers are doing the routine elective procedures themselves. From firsthand experience and extension courses provided for them they have also learned how to diagnose and treat many. of the common diseases of farm livestock. Many veterinary pharmaceuticals antimicrobials and biolOgicals can now be purchased by producers from either veterinary or nonveterinary sources.
INDUSTRIALIZED ANIMAL AGRICULTURE
The intensification of animal agriculture has created complex
animal health and production problems for which there are no
simple and reliable therapeutic and preventive procedures, and
this has made the task of the veterinarian much more challenging.
For example, acute undifferentiated respiratory disease is a
common disease of feedlot cattle that is difficult to treat and
control effectively because the etiology and epidemiology are
complex. Acute diarrhea of calves under 30 days of age may be
caused by several different enteropathogens but a knowledge of
the risk factors or epidemiological determinants such as colostralimmunity and population density is probably more important for effective clinical management and control of the disease. The rearing of pigs intenSively and in complete confinement' has exaggerated a number of disease problems, many exacerbated by inadequacies of the environment.
Suboptimal reproductive performance due to a variety of
management and environmental factors is common, and pneumonia in growing and finishing pigs may be almost impossible to eradicate unless the herd is depopulated and repopulated with minimal-disease breeding stock. Infectious diseases such as porcine reproductive and respiratory syndrome are difficult to control. The solutions to these complex problems are not always readily apparent, in part because of insufficient research on etiology and epidemiology and different control strategies in the herds where the problems are occurring. The veterinarian must be knowledgeable and skillful in the principles of epidemiology, applied nutrition and animal housing, the education and training of animal attendants and the analysis of production indices, including profit and loss, which includes the use of computers, in addition to being skilled in the traditional veterinary diSCiplines of medicine, reproduction, pharmacology and pathology. Thus, the food-producing-animal practitioner must become more skilled in the simultaneous management of animal health and
production; the modern livestock producer is cost-conscious and anything veterinarians do or recommend must be cost-effective.
COMPANION ANIMAL PRACTICE
In contrast, developments in companion animal medicine (small animals) have followed in the footsteps of human medicine with an ever-increasing emphasis and reliance on extensive use of clinical pathology for the in-depth evaluation of the hematology, clinical chemistry, enzymology, immune status and many other body functions of the individual animal.
Diagnostic techniques such as ultrasonography, endoscopy,
nuclear imaging and computed tomography are being used both in veterinary teaching hospitals and in referral veterinary
practices. These in -depth' diagnostic workups' presumably lead to a greater understanding of the etiology and pathophYSiology of disease, with the ultimate aim of a more accurate and early diagnOSiS that allows much more effective medical and surgical therapy than is economically possible or necessary in foodproducing animals. There is not the same emphasis on the efficiency of production, epidemiology and cost-effectiveness that constantly faces the food-producing-animal practitioner.
More and more companion animal owners, because of the
sentimental value of their animals and the growing importance
of the human-companion-animal bond, are willing to pay for the costs associated with extensive laboratory and sophisticated
diagnostic tests and intensive and prolonged veterinary hospital
care. Palliative care for dogs and cats affected with diseases that may not be curable over the long term is now a recognized fact in small-animal practice.
EQUINE PRACTICE
Equine practice has evolved along similar lines to small-animal
practice. Some aspects of it, such as reproduction, intensive
clinical care of the newborn foal and the treatment of medical
and surgical diseases of valuable athletic and competitive horses, have advanced a great deal. The great strides that have been made in our understanding of the diagnosis, prognosis and medical and surgical therapy of colic in the horse are due to the in -depth diagnostic laboratory work and the medical and surgicalexpertise that have been used. Our improved understanding of the prognosis of equine colic has in part been due to prospective studies of the clinical and laboratory findings in horses with colic.
However, the large advances in improvement in survival made in the early years of surgical and intensive medical treatment of
colic have not continued, and there is an urgent need for
appropriately designed prospective clinical trials to determine
optimal treatment regimes in these horses. The same is true for
intensive treatment of sick foals. In addition to the advanced
diagnostic and therapeutic procedures being done on valuable
horses at veterinary teaching hospitals, there are now many
privately owned equine veterinary centers that provide the same service. Undoubtedly the high financial value of some horses has provided the impetus for the development of these services.
While the increasingly sophisticated diagnostic and therapeutic
techniques used in equine practice are readily noted,
advances in the understanding of infectious and contagious
diseases of horses has also increased markedly. This is particularly true for economically important diseases that have the potential to affect large numbers of horses, consequently causing disruption to important athletic events, sales and shipment of horses. These diseases are typically the infectious respiratory diseases and those diseases, such as African horse sickness, that are exotic to most of the horse population worldwide. The economic incentive to control these diseases has resulted in considerable increases in knowledge of their etiology (and consequently vaccinology), epidemiology, immunology, diagnosis and prevention. Few advances have been made in treatment of what are for the most part self-limiting diseases with low case fatality rates.
CONTRASTING OBJECTIVES
It is clear that there are major differences between the objectives and principles of companion-animal practice and those of foodproducing-animal practice. In companion -animal practice, the objective is the restoration of the clinically ill animal to a normal state, if possible, or in some cases a less than normal state is acceptable providing it is a quality life, using all the readily available diagnostic and therapeutic techniques that can be afforded by the client. In sharp contrast, in food-producinganimal practice, the objective is to improve the efficiency of animal production using the most economical methods of diagnosis, treatment and control, including the disposal by culling or slaughter of animals that are difficult to treat and are economic losses.
This growing dichotomy in the delivery of veterinary services
to the food-producing-animal owner and to the companionanimal
owner prompted us to present a short introductory
commentary on the objectives and principles of food-producing
animal practice.
The objectives of food-producing animal practice
EFFICIENCY OF LIVESTOCK PRODUCTION
The most important objective in food-producing-animal practice is the continuous improvement of the efficiency of livestock production by the management of animal health. This involves several different but related activities and responsibilities, which include the following:
• Providing the most economical method of diagnosis and
treatment of sick and injured animals and returning them to
an economically productive status, or to a point where
slaughter for salvage is possible in the shortest possible timeThe financially conscious producer wants to know the
probability of success following treatment of a disease in an
animal and to minimize the costs of prolonged
convalescence and repetitive surgery
• Monitoring animal health and production of the herd on
a regular basis so that actual performance can be compared
with targets and the reasons for the shortfalls in production
or increases in the incidence of disease can be identified as
soon as possible, so that appropriate and cost-effective
action can be taken. The routine monitoring of production
records and the regular monitoring of bulk tank milk somatic
cell counts in dairy herds are examples
• Recommending specific disease control and prevention
programs such as herd biosecurity, vaccination of cattle
against several important infectious diseases that occur
under a variety of conditions, and the strategic use of
anthelmintics in cattle and sheep
• Organizing planned herd and flock health programs for
the individual farms with the objective of maintaining
optimum productivity through animal health management.
This subject is presented in the companion volume to this
book, Radostits OM Herd Health: Food Animal Production
Medicine, 3rd edn. WB Saunders, 2001
• Advising on nutrition, breeding and general
management practices. Food-producing-animal
practitioners must be interested in these matters when they
affect animal health. It is a large part of production-oriented
health management, and it is now common for veterinarians
to expand their health-oriented animal husbandry adviSOry
service to include an animal production advisory service. To
do so is a matter of individual preference, an option that
some veterinarians take up and others do not. Some
veterinarians will rely on consultation with agricultural
scientists. However, veterinarians still require a working
knowledge of the relevant subjects, at least enough to know
when to call in the collaborating advisor for advice. Members
of both groups should be aware of the extensive list of
subjects and species-oriented textbooks on these subjects,
which should be used to support this kind of service.
ANIMAL WELFARE
Encouraging livestock producers to maintain standards of animal
welfare that comply with the views of the community is
emerging as a major responsibility of the veterinarian. The
production of food-producing animals under intensified
conditions has now become an animal welfare concern that
practitioners must face and in which they must become
proactive.
ZOONOSES AND FOOD SAFETY
Promoting management practices that ensure that meat and milk
are free of biological and chemical agents capable of causing
disease in humans must also become a preoccupation for foodproducing-
animal veterinarians. This is because the general
public is concerned about the safety of the meat and milk
products it consumes and the most effective way to minimize
hazards presented by certain infectious agents and chemical
residues in meat and milk is to control these agents at their point
of entry into the food-chains, namely, during the production
phase on the farm. Veterinarians will undoubtedly become
involved in the surveillance of the use of antimicrobial
compounds and other chemicals that are added to feed supplies
to promote growth or prevent infections, and will be expected to minimize the risk of the occurrence of zoonotic disease agents in farm animal populations.
