Modern, intensive fox breeding implies a human-animal relationship but human contact causes stress in farm-bred blue foxes. Handling is a common part of routine farming practices, particularly during the breeding season. The purpose of this study was to determine how handling influences certain morphometric and hormonal parameters of adrenocortical and ovarian function and fertility in pregnant blue foxes and whether these effects are mediated through an increase in plasma concentrations of cortisol. Blue fox females were subjected to a 1-min daily-handling treatment in the last trimester of pregnancy (term = 52 days). Plasma concentrations of ACTH, cortisol, progesterone, oestradiol and testosterone, as well as the in vitro adrenal and gonadal production of steroids were measured by radio-immuno assay in control (C, no. = 6) and handled (H, no. = 7) vixens on days 47 to 48 of pregnancy. In addition, the number of viable and dead foetuses, body, adrenal and ovarian weights in pregnant foxes and body weights of their viable foetuses were recorded. Handling increased plasma concentration of cortisol (C: 6·8 (s.e. 1·6) ng/ml v. H: 22·8 (s.e. 5·9) ng/ml, P < 0·05) as well as in vitro adrenal production of cortisol. In addition, handling decreased the body (C: 7·40 (s.e. 0·48) kg v. H: 6·24 (s.e. 0·13) kg, P < 0·05) and ovarian (C: 3·45 (s.e. 0·26) g v. H: 2·73 (s.e. 0·17) g, P < 0·05) weights of pregnant vixens and also the body weight of viable foetuses (C: 59·1 (s.e. 0·9) g, no. = 73 v. H: 50·6 (s.e. 1·2) g, no. = 58, P < 0·01). Handling did not cause any changes in adrenal weight, plasma concentrations of progesterone and oestradiol or in vitro ovarian steroid production. It is concluded that persistent handling of pregnant blue foxes is a mild stressor, which results in an increase in plasma concentration and adrenal production of cortisol and reduces maternal and foetal body weights.

Under field conditions, ewe behaviour was quantified by maternal behaviour score (MBS)-a six-point scale which assesses ewe flight distance when lambs are handled for the first time, within 24 h of birth (adapted from O’Connor et al., 1985). MBS was measured on 847 Scottish Blackface ewes on two experimental hill farms, over a maximum of four parities. Live weights of lambs born to these ewes were measured at birth, marking (average age of 42 days) and weaning (average age of 120 days).

MBS was significantly higher ( P < 0·05) for ewes with more lambing experience (multiparous ewes), for older ewes and for twin-bearing ewes compared with ewes with single lambs. MBS was under genetic control ( h2 = 0·13, permanent environmental effect = 0·19, when analysed as the same trait across parities) and the repeatability was 0·32.

MBS had no significant effects on weight gain of lambs. However, a moderate, positive genetic correlation was estimated between MBS and the average weight gained by lambs from birth to marking ( rg = 0·4, s.e. 0·22), although the genetic correlation estimated between MBS and weight gained to weaning was close to zero ( rg = 0·02, s.e. 0·16). Ewes with a MBS of 1 (ewe flees and does not return to her lambs) had significantly more lambs dying before marking and weaning than ewes with a higher maternal behaviour score. Selection to reduce the proportion of ewes in this category may therefore be beneficial.