Relocation shortly after mating does not have a major impact on stress responses and reproduction in female farm mink.

@enOn farms, female mink are exposed to acute stressors multiple times due to handling, capturing and transport with restricted movement being a typical part of the mating procedure. We hypothesised that no relocation (group NON; i.e. omitted from one trapping and one transport to a novel cage) or direct relocation after second mating (group DIRECT; i.e. omitted from one capturing) reduces female mink's stress responses (indicated by cortisol and stereotypy) and thereby influences maternal care (nest building, nest climate and offspring retrieval) and consequently potentially improves the reproductive output (litter size Day 0-7, offspring mortality and growth) compared to a regular farm relocation procedure (group REGULAR). In numbers, group NON had lower faecal cortisol metabolite (FCM) concentrations, but relocation did not with statistical significance influence the FCM concentrations prior to (NON: 66 +/- 8.4 ng/g vs. DIRECT: 115 +/- 47.5 ng/g vs. REGULAR: 96 +/- 20.0 ng/g; F-1,F-112 = 0.7, P = 0.49) and after parturition (NON: 65 +/- 7.2 ng/g vs. DIRECT: 79 +/- 14.6 ng/g vs. REGULAR: 84 +/- 13.6 ng/g; F-2,F-109 = 0.3, P = 0.72); nor did the relocation procedure elicit a different performance of stereotypic behaviour (6 +/- 2.1 vs. 3 +/- 1.4, F-2,F-121 = 1.2, P = 0.30). The nest score differed between groups (F-2,F-201 = 6.9, P = 0.001;) as group DIRECT (3.2 +/- 0.04) had a significantly higher nest score than group NON (2.9 +/- 0.07; P < 0.001) and a tendency to a higher nest score than group REGULAR (3.0 +/- 0.06; P = 0.070). Likewise, there was a tendency that REGULAR had a higher nest air temperature compared to NON (P = 0.055). NON (19.3 +/- 0.10 degrees C) had a significantly higher daily mean nest air temperature compared to DIRECT and REGULAR (17.9 +/- 0.13 degrees C and 18.3 +/- 0.14 degrees C; P < 0.001). The difference in nest score and nest air temperature could be due to group NON being in a shed with a slightly higher temperature (8.9 +/- 0.21 degrees C) compared to the shed containing most of the animals in groups DIRECT and REGULAR (8.3 +/- 0.19 degrees C). The three relocation strategies NON, DIRECT and REGULAR did not affect litter size or offspring growth. We conclude that relocation of mink dams shortly after mating is not a major stressor, as we can only report a minor effect on FCM concentrations during the gestation, and detected no effect on the performance of stereotypic, maternal care or reproductive outcome using alternative procedures.

Veterinärmedizinische Universität Wien
Aarhus university