Out of rut, male red deer (Cervus elaphus) associate themselves in bachelor groups where animals compete for rank position via agonistic interactions. In a previous study on red deer, males were recognized either as "Non-Fighters" (NF, low frequency of attacks) or "Fighters" (F, high frequency of attacks). This study, therefore, aims to verify the consistency of the inter-individual differences in fighting attitude across different social contexts and investigate whether they could be considered an individual characteristic. Behavioral consistency was presumed across three different sampling seasons, assuming that NF would have lower cortisol (C) and testosterone (T) concentrations than the F males. In 2015 the males were kept in one large group and labelled NF and F. In 2016, the herd was divided into two subgroups ("NF" and "F") based on the frequency of attacks. Finally, in 2017, the males were divided into two randomly composed subgroups. Data about agonistic behavior and concentration of C and T were collected during each season. In 2015 the individuals differed only for the fighting attitude. After the division, the frequency of the attacks always increased, being consistently lower in NF than in F. Unexpectedly, a slight increase in the concentration of C was detected in the NF in 2016, compared to the F who experienced no difference neither in 2015 nor 2017. No significant differences were found in T. We concluded that, even though the males had shown behavioral plasticity, their diversified interaction-prone attitude had been maintained despite the modifications of the social environment.

• MeSH
• Agonistic Behavior MeSH
• Behavior, Animal * MeSH
• Hydrocortisone metabolism   MeSH
• Antlers growth & development   MeSH
• Seasons MeSH
• Body Weight MeSH
• Testosterone metabolism   MeSH
• Deer growth & development   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Bone ash, collagen, Ca and P composition, are considered the main factors affecting mechanical properties in bones. However, a series of studies in bone and antler have shown that some trace minerals, such as manganese, may play a role whose importance exceeds what may be expected considering their low content. A previous study showed that a reduction in manganese in antlers during a year of late winter frosts led to generalized antler breakage in Spain, which included a reduction of 30% of cortical thickness, 27% reduction in impact energy, and 10% reduction in work to peak force. Starting for this observation, we experimentally studied the effects of manganese supplementation in adults and yearling (yearlings) red deer under a balanced diet. Subjects were 29 deer of different age classes (adult n = 19, yearlings n = 10) that were divided in a manganese injected group (n = 14) and a control group (n = 15). Antler content in ashes and minerals, intrinsic mechanical properties and cross section structure were examined at 4 points along the antler beam. A one way ANOVA (mean per antler) showed that in yearlings, manganese supplementation only increased its content and that of Fe. However, in adults, Mn supplementation increased the mean content per antler of Ca, Na, P, B, Co, Cu, K, Mn, Ni, Se (while Si content was reduced), and impact work but not Young's modulus of elasticity, bending strength or work to peak force. A GLM series on characteristics in the uppermost part examined in the antler, often showing physiological exhaustion and depletion of body stores, showed also a 16% increase in work to peak force in the antlers of the treated group. Thus, manganese supplementation altered mineral composition of antler and improved structure and some mechanical properties despite animals having a balanced diet.

• MeSH
• Biomechanical Phenomena MeSH
• Diet MeSH
• Linear Models MeSH
• Manganese administration & dosage   MeSH
• Minerals metabolism   MeSH
• Antlers chemistry   ultrastructure   MeSH
• Dietary Supplements analysis   MeSH
• Deer anatomy & histology   growth & development   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

In this review, we analyze endocrine aspects of the relationships between antlerogenesis and rank-related behavior. The explanation of these relationships has been based on the presumption that the antler growth is regulated by hormones modulated by agonistic behavior. Originally, we assumed that these relationships are primarily testosterone dependent. In the eighties, it was reported that the insulin-like growth factor 1 (IGF-1) is the antler-stimulating hormone. This hypothesis was supposed to replace an earlier theory that the antler-stimulating hormones are either androgens or their derivatives. Here, we present historical and recent views on these issues. In particular, we analyze the arguments in favor and against the role of testosterone and IGF-1 in antler growth and present a comparison of the results obtained across some deer species. In this context, we review and discuss experiments with castration of various deer species and analyze data from papers dealing with in vivo studies. We conclude that testosterone and not IGF-1 is the main antler stimulating and regulating hormone, and that concentrations of testosterone may be modified by social behavior.

• MeSH
• Behavior, Animal MeSH
• Endocrine Glands physiology   MeSH
• Antlers growth & development   MeSH
• Deer growth & development   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH