Morphometric and hormonal changes following persistent handling in pregnant blue fox vixens (Alopex lagopus)

Modern, intensive fox breeding implies a human-animal relationship brit hum an 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 mor phometric and hormonal parameters of adrenocortical and ovarian function an d fertility in pregnant blue foxes and whether these effects are mediated t hrough an increase in plasma concentrations of cortisol. Blue fox females w ere subjected to a 1-min daily-handling treatment in the last trimester of pregnancy (term = 52 days). Plasma concentrations of ACTH, cortisol, proges terone, oestradiol and testosterone, as well as the in vitro adrenal and go nadal 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 ov arian weights in pregnant foxes and body weights of their viable foetuses w ere 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 riot caus e any changes in adrenal weight, plasma concentrations of progesterone and oestradiol or in vitro ovarian steroid production. It is concluded that per sistent handling of pregnant blue fetes is a mild stressor, which results i n an increase in plasma concentration and adrenal production of cortisol an d reduces maternal and foetal body weights.