Improving the Adaptability of Animals by Selection - Genetics and the Behavior of Domestic Animals - page 289

PHARMACOLOGY
This approach was first tested in the 1950s and 1960s after neuroleptic drugs
were discovered ( Gilbreath et al., 1959 ). Pharmacology was used in an
attempt to calm animals during harvesting and transport. The early use of
neuroleptic drugs as tranquilizers was unsuccessful. Furthermore, consumer
awareness of drug residues makes such methods unacceptable for commer-
cial use. However, pharmacological research can provide useful insights into
animal behavior, adaptability, and brain function.
SURGERY
Surgical methods such as dehorning, beak trimming, or tail docking in domestic
animals can prevent welfare problems such as pecking injuries and tail biting.
However, these methods are criticized by welfarists because pain is experienced
at the time of the operation. Gentle et al.(1991) found that beak trimming in
poultry may cause pain for a prolonged period of time after the operation.
ONTOGENY
Some problems which make it difficult for production animals to adapt to
their rearing environment can be improved to some degree by ontogenetic
processes such as handling or environmental enrichment ( Jones, 1982; Jones
and Faure, 1981; Jones et al., 1991 ). Ontogenetic manipulation involves
manipulation of the animal's early experiences. The disadvantage of these
procedures is that they are environmental rather than genetic and they must
be repeated in subsequent generations.
GENETIC SELECTION
Adaptation of animals to their environment can also be improved by genetic
selection. This method has the advantage of being applied to relatively small
numbers of carefully selected breeding animals with subsequent genetic gain
being transmitted to their descendants. This chapter will focus on the use
of genetic selection and its applicability to practical problems that occur in
intensive husbandry systems. Genetic selection can be used to improve
welfare. Although it is unlikely that genetic selection alone can be used to
solve all welfare problems, a combination of improvement of the environment
and ontogenetic processes, together with the use, at least in emergency cases,
of pharmacology or surgery is probably the only realistic way of improving
domestic animal welfare (see Chapter 11).
Genetic selection has influenced the processes of domestication in at least
two ways (see also Chapter 2). These are natural selection and artificial
selection for specific traits. When animals were first domesticated, natural