Stress evaluation in hares (Lepus europaeus Pallas) captured for traslocation

Abstract

With the aim to evaluate the capturing techniques some haematic and physiological parameters were studied to discriminate stressed hares from non stressed hares.A total of 66 wild hares (experimental group) were sampled in 14 different non-hunting areas, where hares are usually captured for later release in low-density areas. In the same season a total of 30 hares (about 1 year old), reared in cages and thus showing a reduced fear of man, were sampled (control group). In each area the hares were captured by coursing with 3-4 dogs (greyhounds or lurches). The dogs were released by the different hunter teams to find and drive into trammel nets any hare that was seen running. After capture, the hares remained inside darkened, wooden capture-boxes for a variable period of time before blood drawing. For blood sample collection all the hares were physically restrained and their eyes immediately covered. Blood, always collected within 1-2 minutes, was drawn from the auricular vein. Blood samples (plasma) were analysed for glucose, AST, ALT, CPK and cortisol concentrations. Body temperature, heart and respiratory rate, sex, and age were evaluated in each hare. The effect of origin, sex and age on haematic and physiological parameters was analysed by ANOVA. Every measured parameter of the hares bearing to the capture group or the control group (reared) was then subjected to stepwise and to discriminant analysis, in order to select the groups of stressed (discriminated by the controls) and non-stressed hares.CPK, AST and glucose were found to be the best parameters for distinguishing stressed from non-stressed hares. The intensive exercise suffered by the wild hares induced a depletion of energetic reserves, so that most of the captured hares showed lower glucose and higher CPK activity in the plasma, probably due to muscle damage (P< 0.05). After reclassifying the hares in the two groups of stressed and non stressed hares, the reference values (means ± SE) resulted as follows: estimated non-stressed hares, glucose 234 ± 9 .4 mg/dl, AST 112 ± 22.2 U/l, CPK 1334 ± 734 U/l; estimated stressed hares, glucose 128 ± 7 mg/dl, AST 164 ± 13 U/l, CPK 4658 ± 454 U/l.These three cheap and quickly analysable analytes can be useful to the game manager in detecting stressed and non stressed hares, in order to improve the capturing techniques by the evaluation of the following relationship: (number of stressed hares + number of the dead hares during the capture)/number of total captured hares.