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Cate Dewey presents Keynote paper 4
In session 4: Assessing health status of groups of animals in relation to welfare
Friday, 12 September 2008 from 8h30-9h00 in the Aula chaired by Jeffrey Rushen
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Keynote paper 4
ASSESSING THE HEALTH STATUS OF POPULATIONS OF ANIMALS IN
RELATION TO WELFARE
C.E. Dewey
Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada N1G 2W1
The welfare of a population of animals may be measured by welfare of the one animal in the
population with the poorest welfare condition. There is a wide spectrum of “health” that ranges
from the clinically healthy animal that is expressing its full potential for health, growth, play and
wellbeing to the animal that is dead. In between these we will find animals that are sub-clinically
ill; those that show no measurable signs of illness but may have an infectious disease and are not
fully well, to those with measurable clinical abnormalities, to moribund. A population with an
infectious disease will include animals at each level of this spectrum.
Many tools are used to determine the health status of a population including serological profiling to
determine when the population is becoming infected with a disease agents and conducting post
mortem evaluations on animals that have died. Next, we establish treatment, management and
prevention protocols to reduce the welfare implications of the infectious diseases. Finally, we
evaluate whether our recommended treatments improve or reduce the welfare of the animals. Field
trials on commercial farms including thorough follow-up of the animals enable us to evaluate our
interventions.
Poor health is often a direct consequence of management decisions. Data collected for production
practices may be used to research these associations. This is particularly useful for rare events such
as in-transit deaths (0.16%). Multiple variable modeling provides the foundation for the strength of
this research. Hierarchical dummy variables may be used to identify thresholds of parameters, such
as temperature, above which in-transit losses increased.
In conclusion, health represents a wide spectrum of welfare states. Understanding the health of a
population enables us to determine the welfare of the animal most adversely affected.
Contact information: Cate Dewey or email cdewey@ovc.uoguelph.ca
Complete address: Population Medicine, Ontario Veterinary College, University of Guelph, Guelph,
Ontario, Canada N1G 2W1
Species: General