Effects of public vs. private management on deer antler composition, mechanical and structural variables

Previous studies have shown that antler mineral composition reflects diet. Thus, management involving diet can influence both the mineral composition and mechanical properties of antlers. However, it is not known if reducing population density, which increases availability of food, can compensate mineral deficiencies arising from lack of minerals in plants and, ultimately, in the soil. The present study aimed at assessing if private management often involving a balanced food supplementation produced differences in antler properties compared to both public management and reference antlers from deer farms. We also examined if low population density in a National Park could compensate for mineral deficiencies found in antlers of other public reserves or else, antlers still differed in antler characteristics compared to supplemented deer in private game estates. We used 120 antlers from three public reserves, four private game estates and two deer farms as reference to assess antler composition, mechanical properties, size and structure. Public managed antlers had shorter length compared to private and reference ones, thinner cortex (CT), were less dense, had lower second moment of area (I) and work to fracture (W). In addition, they had content in ash, Ca, Mg, Na, S and Zn lower than antlers from private game estates. In contrast, antlers from public reserves had greater values of Young’s modulus of elasticity (E), Fe, Mn and Si. In most cases, antlers from private management and reference farms showed similar values. When comparing antlers from low population density in a National Park with antlers from private management, differences in antler length, CT, I and ash disappeared, but both differed still in density, E, bending strength, W and content in all minerals mentioned. In conclusion, low density can improve some structural variables, but it cannot compensate for mineral deficiencies whereas food supplementation can.