Behavioral Genetics in Pigs and Relations to Welfare - Genetics and the Behavior of Domestic Animals - page 393

Chapter 11

Behavioral Genetics in Pigs
and Relations to Welfare

Lotta Rydhmer * and Laurianne Canario †
*Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences,
Uppsala, Sweden; † French National Institute for Agricultural Research, Animal Genetics
Division, Castanet-Tolosan, France

INTRODUCTION
The human global population is growing and there is an increased demand
for pork. At the same time, the competition for agricultural land is increasing
and the negative environmental influence of pig production must be
decreased. Thus, there is a need for increased efficiency at all levels of the
production chain, starting with the pig's genotype. But intense selection for
production traits such as feed efficiency may decrease welfare, for example,
by decreasing the capacity to adapt to stress. The challenge is to increase
efficiency without decreasing pig welfare.
The domestication of the pig started approximately 10,000 years ago.
Since then the animal has developed from a small wild boar sow giving birth
to a litter of six slow-growing fat pigs once a year to today's large sow,
which produces 25 fast-growing lean pigs a year. During the long process of
domestication, pigs' behavior has changed genetically. Fear of humans has
decreased and the pigs have become much easier to handle. More recently,
the genetic progress in production traits has been enormous. However, breed-
ing may threaten animal welfare due to undesirable correlated effects in
behavior, metabolism, reproduction, and health traits. Fortunately, the
genetic tools that have been used to increase production can also be used to
decrease negative side effects of selection and improve traits important for
welfare.

PIG BEHAVIOR
Explorer and Generalist
Pigs have extensive social skills and relatively low sensitivity to confine-
ment;

traits that favored domestication. After generations of successful