readily explicable. One hypothesis is that HSR line chicks tend to be more strongly imprinted on each other and the human caretaker. However, SR behaviour is highly species specific in both
lines, existing evidence for line differences in social discrimination is limited and birds of the two lines show similar duration of the TI response. Despite this, whatever their underlying causation,
these results demonstrate that genetic selection can be used to reduce negative reactions to human beings and may be of value in the improvement of both animal welfare and productivity. q 2000
Elsevier Science B.V. All rights reserved.
Keywords: Japanese quail; Coturnix japonica; Capture; Fear; Stress; Sociality; Genetics; Welfare
1. Introduction
Whatever the species of animal or the type of husbandry system considered, interactions between humans and animals are of importance with respect to both
production traits and welfare. Human activity is a frequent cause of disturbance in many husbandry systems. Such disturbance may cause falls in production and welfare
Ž .
Hemsworth and Barnett, 1989; Hemsworth et al., 1989; Seabrook, 1990 . In the case of large animals such as cattle, the stockman risks injury or even death if husbandry
practices are such that the animals become aggressive or make intemperate attempts at Ž
. flight or avoidance Le Neindre et al., 1994 . In smaller species, contact with humans
Ž may lead to fear, distress and adverse effects on production traits Rushen and de
. Pasille, 1992; Hemsworth et al., 1994; Jones, 1996 . For examples, in poultry, aversive
manipulations during ‘harvesting’ and transport prior to slaughter can lead to stress and Ž
. consequent falls in meat quality Duncan et al., 1986; Remignon et al., 1998 and
inappropriate fear reactions may lead to panic and the death of birds because of suffocation or trampling as hundreds or even thousands of birds crowd in to the corners
Ž .
of the poultry house Mills and Faure, 1990a . Furthermore, all or any of the above may lead to negative public opinion concerning the husbandry and management of domestic
Ž .
animals Faure and Mills, 1995 . Despite the evident importance of interactions between humans and animals, there
appear to have been few studies of such interactions under conditions that approach those found in commercial husbandry systems. Environmental or ontogenetic influences
on animals’ responses to humans have been extensively studied in both birds and Ž
mammals under experimental conditions examples include: Murphy and Duncan, 1977, 1978; Gross and Siegel, 1979; Jones, 1985, 1987, 1993; Jones and Faure, 1981; Jones
and Waddington, 1992; Jones et al., 1981; Boissy and Bouissou, 1988; Pedersen and .
Jeppersen, 1990; Barnett et al., 1993; Hemsworth and Jones, 1993 . However, the role of Ž
genetic factors in human–animal reactions has received less attention exceptions
include: Belyaev, 1978; Belyaev and Trut, 1975; Belyaev et al., 1985; Bessei et al., .
1983; Le Neindre et al., 1994; Satterlee and Jones, 1997 . This apparent lack of attention to genetic factors in the improvement of human–animal interactions is surprising for
Ž .
Ž .
three reasons. First, as Mench 1992 and Mills et al. 1987 suggest, genetic selection may be a powerful tool for decreasing the incidence of welfare problems. Second,
various studies have shown that domestic animals are more docile than their putative
Ž wild ancestors Poole, 1972; Desforges and Wood-Gush, 1975; Ajayi et al., 1978; Saad
. et al., 1984 . Third, limited evidence, that selection for the quality of human–animal
Ž relationships is possible already, exists Belyaev and Trut, 1975; Le Neindre et al.,
. 1994 .
In the present study, we studied the effects of selection for duration of the tonic Ž
. Ž
. Ž
. immobility TI response a putative measure of fearfulness or social reinstatement SR
Ž .
motivation a putative measure of sociality on the ease of capture of Japanese quail at Ž
. various ages. We also studied the consistency ‘repeatability’ of individual capture
ranks at different ages.
2. Materials and methods
