Relationship between plasma cortisol level and bodyweight and antler size in farmed fallow deer

K Dziki-Michalska,K Tajchman,M Bogdaszewski,S Kowalik

doi:10.4314/sajas.v51i3.9

K Dziki-Michalska, K Tajchman + Show 2 more

Open Access

https://doi.org/10.4314/sajas.v51i3.9

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Abstract

The aim of this study was to demonstrate the relationship between the plasma cortisol level and bodyweight and antler size in farmed male fallow deer (Dama dama) of various ages. The study involved 33 animals divided into three age groups: one year old, three years old, and older. Their bodyweight was measured and blood samples were taken twice a year during antler growth (May) and before the rut (September). Whole antlers were collected in September to measure their length and weight. The plasma cortisol concentration was determined with an immunoenzymatic method. The correlations between cortisol level and bodyweight were significant and positive in both May and September (P ≤0.05). There was a negative correlation between weight gain and change in cortisol levels (P ≤0.05). Thus, fallow deer with large seasonal changes in cortisol gained less weight from May to September. The results of the present study indicated that calmer animals with lower cortisol fluctuations should be selected for breeding, which would contribute to greater stability of weight gain.

Highlights

Significant differences were found between hormone levels in May and September (P =0.04 and P =0.012,) and changes in the cortisol concentration (P =0.023) between measurements
At the first hormone determination of level (May), a statistically significant difference was noted between groups I and II (P ≤0.05) and between group I and III) (P ≤0.05)
A difference was noted between the youngest animals and group II (P ≤0.05)

Summary

Introduction

Farm rearing of cervids has been developing in Europe and worldwide, albeit with varied intensity. Male cervids exhibit a sharp rise in aggressive behaviour during rut, which should be taken into account in their management to avoid potentially lethal fighting (Bartoš & Bubenik, 2011). These animals have to be immobilized temporarily during deworming, marking, cutting antlers, health screening, and dividing into rearing groups,. The animals are driven from pastures into small manipulation pens. They are immobilized inside handling boxes during these treatments, which are associated with exposure to high levels of stress (Mattiello, 2009; Janiszewski et al, 2016). Heightened stress levels tend to cause imbalances in hormones such as cortisol, dehydroepiandrosterone and adrenaline (Ranabir & Reetu, 2011)

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