Juvenile-to-Adult Antler Development in White-Tailed Deer in South Texas

Abstract: Past studies using penned deer provide conflicting results on the age when reliable predictions about antler growth potential in white-tailed deer (Odocoileus virginianus) can be made. We captured wild whitetail males via aerial net gun on 12 ranches in 5 counties in south Texas, USA, from 1999 to 2007 to determine if a reliable juvenile-to-adult relationship in antler development existed. We individually marked and released captured animals at the trap site after we took antler and body measurements. We recaptured marked animals as possible in subsequent years or until we obtained final measurements after legal harvest. Amount of growth in the first set of antlers in whitetail males was a poor predictor of antler growth at maturity. By 4.5 years of age there were no differences (P > 0.05) in antler measurements regardless of the amount of development of the first set of antlers at 1.5 years. We concluded culling of yearling males based on number of antler points would have little positive effect on overall antler quality in future years.     

Influence of Landscape Composition and Structure on Antler Size of White-Tailed Deer

Abstract: Cause for spatial variation in phenotypic quality of white-tailed deer (Odocoileus virginianus) populations is of great interest to wildlife managers. Relating phenotypic variation of populations to large-scale land-use patterns may provide insight into why populations exhibit spatial variation and elucidate how management can influence population phenotype. We used an information-theoretic approach to relate average antler size of 203 deer populations to composition and structure of the habitat occupied by those populations. We used interspersion, edge, and diversity indices to represent habitat structure and percentage of area in vegetation types to represent habitat composition. Landscape composition was a better predictor of deer population antler size than was landscape structure. Percentages of the management unit in agriculture, pasture, and pine forest were variables commonly found in the region-specific set of best models. Model-averaged estimates of agriculture and pasture parameters were always positive and estimates of pine forest parameters were always negative, which suggests that land-use types that promote growth of early successional herbaceous plants will positively influence antler size and, most likely, body growth and reproduction of white-tailed deer populations. Conversely, our findings suggest landscapes dominated by pine forests did not provide optimal amounts of quality forages for white-tailed deer. Pine forest effects should be mitigated using a combination of increased harvest to lower deer density and silvicultural practices like thinning, prescribed burning, and selective herbicide applications that stimulate growth of high-quality forages beneath the forest canopy to improve deer phenotypic quality.     

Non‐trophic plant–animal interactions mediate positive density dependence among conspecific saplings

Trophic plant–animal interactions (e.g. browsing by ungulates, insect attack) are an important and well‐studied source of mortality in many tree populations. Non‐trophic tree–animal interactions (e.g. deer antler rubbing) also frequently lead to tree death, and thus have significant effects on forest ecosystem functioning, but they are much less well studied than trophic interactions are. As deer populations have increased in recent decades in the Northern Hemisphere, their impact on tree populations via browsing and antler rubbing will increase. The aim of the study was to illustrate the potential ability of non‐trophic plant–animal interactions to regulate the dynamics of a natural forest. Specifically, we wanted to determine whether and how density and distance‐dependent processes affect sapling mortality caused by an antler rubbing by red deer Cervus elaphus. We used a spatially explicit approach to examine density and distance‐dependent mortality effects in almost two thousand Picea abies saplings over 20 years, based on a fully mapped permanent 14.4 ha plot in a natural subalpine old‐growth spruce forest. Antler rubbing by deer was the main identified cause of sapling mortality, and it showed a strong spatial pattern: positive density dependence of survival among spruce saplings. Deer selectively killed spruce saplings that were isolated from conspecifics. In consequence, non‐trophic plant–deer interactions were a major driver of the spatial pattern of P. abies sapling survival. The other mortality causes (e.g. breaking, overturning) did not show density‐dependent patterns or their effects were much weaker. In the medium and long term, the density‐dependent pattern of sapling mortality due to antler rubbing can alter the tree stand structure. Our results highlight the ecological relevance of non‐trophic plant–animal interactions for forest ecosystem functioning.     

利用全基因组重测序分析鹿茸重量相关基因

茸角是鹿科动物特有的器官,具有重要的生物学意义。鹿茸生长是一个复杂的生物代谢过程,其重量与遗传因素有一定关联。本研究对饲养条件基本一致的5个梅花鹿(Cervus nippon)群体进行调查,获得高产和低产梅花鹿个体共100只,利用全基因组重测序分析这些个体与鹿茸重量相关的遗传变异。结果表明,共得到94个与鹿茸重量可能相关的遗传变异,其中有2个变异位点分别定位于OAS2和ALYREF/THOC4基因的外显子区,且ALYREF/THOC4基因在鹿茸中表达量很高。功能富集分析发现,这些遗传变异与鹿茸生长发育密切相关,可作为潜在的鹿茸重量相关遗传变异。本研究首次通过全基因组重测序直接筛选与鹿茸重量相关的遗传变异,并分析关联基因的生物学功能,对揭示鹿茸生长发育和鹿茸重量差异形成的遗传机制具有重要意义。     

麋鹿鹿角生长周期及影响因子

2013年8月至2014年8月,使用望远镜(SWAROVSKI 8×42 WB)和照相机(Canon 550D 70×300)观察北京南海子59只雄性麋鹿茸的生长和角脱落周期,发现麋鹿角总体趋势呈随着年龄的减少,脱角日期越迟,且等级序位高或者鹿王较年老个体先脱落。收集2012年12月至2014年2月两年度麋鹿自然脱落的角,研究表明,个体而言,左右角脱角顺序差异明显,同一天脱落两角者占17.0%,左角先脱落者占34.1%,右角先脱落者占48.8%,重量重和重量轻的角先脱落的个体各占41.5%,个体成对的左右角脱落时间间隔短,平均为1.98d;群体而言,角重量与脱角时间呈显著负相关,总体呈现角重的个体角先脱落,但不是角最重的个体角第一个脱落。2013年6月至2014年5月,对北京南海子、湖北石首、江苏大丰、天津七里海、浙江慈溪、浙江临安、海南海口、河北滦河上游、辽阳千山等9个地区麋鹿种群麋鹿角脱落起止时间进行调查,研究表明野生种群脱角时间比圈养种群早;迁入热带地区海南的麋鹿仍有规律的角周期;同一栖息地不同年份角周期存在差异,不同栖息地间麋鹿角周期存在差异;脱角起始时间与海拔、经度、纬度、年平均气温、圈养情况和气候类型等影响因子不存在统计学上显著的相关性,但光周期和激素直接主导和调节着角周期,年龄大小、角重量、营养以及与营养相关的能量、种群密度、物候等环境因子均影响角周期。     

Comparison of Effects of Shed Antler Hunting and Helicopter Surveys on Ungulate Movements and Space Use

Shed antler hunting (i.e., collecting cast cervid antlers) has increased in popularity during the past decade, but little is known about how this recreational activity affects ungulate movements and space use. We placed geographic positioning system (GPS)-collars on 133 female and male bighorn sheep (Ovis canadensis), bison (Bison bison), and mule deer (Odocoileus hemionus) to quantify their movements and space use during shed antler hunts compared with those behaviors during helicopter surveys in Utah, USA, from 2012 to 2015. For each species, we calculated means and 95% confidence intervals for distance moved during 90-minute segments (16 points/day) pre-event (control, 7 consecutive days prior to event), event (1–2 days), and post-event (7 consecutive days after event) for shed antler hunts and helicopter surveys. We also compared use of space for each species during these events. Female bighorn sheep did not increase distance moved or substantially change space use during shed antler hunts and helicopter surveys. Male bighorn sheep increased distance moved 41% on average during shed antler hunts and by 2.02 times during helicopter surveys but did not change space use during those events. Female bison increased distance moved 15% on average during shed antler hunts and 30% during helicopter surveys. Mule deer increased distance moved and altered space use the most during shed antler hunts; females increased distance moved 97%, and 54% of females moved a mean distance of 742 ± 642 (SD) m (range = 9–3,778 m) outside of their home ranges during those hunts for a mean of 9.2 ± 9.4 hours (range = 1.5 to 41 hr). Male mule deer increased distance moved by 2.10 times on average during shed antler hunts, and 82% of males moved a mean distance of 1,264 ± 732 m (range = 131–3,637 m) outside of their home ranges during those hunts for a mean of 12.6 ± 7.6 hours (range = 4.5–33 hr). Our results provide timely information about how legal shed antler hunting affects movements and space use of female and male ungulates, especially mule deer, and can guide the conservation of ungulate populations and their habitat. © 2021 The Wildlife Society.     

White-Tailed Deer Antler Research: A Response to Demarais and Strickland

ABSTRACT Demarais and Strickland presented several questions about the scope and validity of conclusions regarding predictability of mature antler size based on yearling antler size and produced a simulation model reported to demonstrate measurement bias in our 2008 study. We believe our conclusions were appropriate with our research hypothesis and demonstrated the assumed differential selection bias by hunters used in Demarais and Strickland was unwarranted. Demarais and Strickland provided no metadata to document the provenance of data used in their model and did not account for location, year, cohort, nutrition of research animals, or loss of individuals from their sample population by accidents or death: the same questions raised in their critique. Additionally, selection and experimental design problems in a portion of their sample population indicate their model results are questionable. Our responses to Demarais and Strickland will aid wildlife managers in making future culling decisions in white-tailed deer management.     

Expression and regulation of Angiopoietins and their receptor Tie-2 in sika deer antler

The cartilage vascularization and chondrocyte survival are essential for endochondral ossification which occurs in the process of antler growth. Angiopoietins (Ang) is a family of major angiogenic growth factors and involved in regulating the vascularization. However, the expression and regulation of Angs in the antler are still unknown. The aim of this study is to localize the expression of Ang-1, Ang-2 and their receptor Tie-2 in sika deer antler using in situ hybridization and focused on analyzing the regulation of testosterone, estrogen, all-trans-retinoic acid (ATRA) and 9cRA on their expression in antler chondrocytes. The results showed that Ang-1, Ang-2 and Tie-2 were highly expressed in antler chondrocytes. Administration of testosterone to antler chondrocytes led to a notable increase in the expression of Ang-1 and Tie-2, and a reduction in the expression of Ang-2. The similar result was also observed after estrogen treatment. In contrast, ATRA and 9cRA could inhibit the expression of Ang-1 in antler chondrocytes and heighten the expression of Ang-2. Simultaneously, ATRA could downregulate the expression of Tie-2 in antler chondrocytes at 12 and 24?h, while 9cRA upregulate the expression of Tie-2 at 3 and 6?h. Collectively, Ang-1, Ang-2 and Tie-2 are expressed in antler chondrocytes and their expression can be affected by testosterone, estrogen, ATRA and 9cRA.     

Enhancement of exercise endurance capacity by fermented deer antler in BALB/c mice

To investigate the activity of fermented deer antler on exercise endurance capacity, we evaluated endurance capacity in five-week-old male BALB/c mice by administering the fermented deer antler extract (FA) or the non-fermented deer antler extract (NFA) and then subjected the mice to exercise in the form of swimming. The mice administered 500?mg/kg/day of FA showed a significant increase in swimming time compared with mice administered placebo (16.55?min vs. 21.64?min, P?<?0.05). Serum lactate dehydrogenase (LDH), the marker of the liver and muscle damage, was significantly lower in FA groups. However, NFA groups did not show significantly different swimming time or serum LDH from that of the control group. Moreover, the FA-500 group had significantly higher hepatic superoxide dismutase (SOD) activity after forced swimming than the control and NFA groups (P?<?0.05). These findings suggest that fermentation may increase the exercise endurance capacity of the deer antler.     

Antler size provides an honest signal of male phenotypic quality in roe deer

Identifying factors shaping secondary sexual traits is essential in understanding how their variation may influence male fitness. Little information is available on the allocation of resources to antler growth in territorial ungulates with low sexual size dimorphism. We investigated phenotypic and environmental factors affecting both absolute and relative antler size of male roe deer in three contrasting populations in France and Sweden. In the three populations, we found marked age-specific variation in antler size, with an increase in both absolute and relative antler size between yearling and prime-age stages, followed by a decrease (senescence) for males older than 7 years. Antler size increased allometrically with body mass. This increase was particularly strong for senescent males, suggesting the evolution of two reproductive tactics: heavy old males invested particularly heavily in antler growth (potentially remaining competitive for territories), whereas light old males grew small antlers (potentially abandoning territory defense). Finally, environmental conditions had little effect on antler size: only population density negatively affected absolute antler size in one of the three populations. Antler size may therefore provide an honest signal of male phenotypic quality in roe deer. We discuss the implications of these results in terms of territory tenure and mating competition.     

POPULATION DENSITY-PHYSICAL CONDITION RELATIONSHIPS IN WHITE-TAILED DEER

Abstract: Management of white-tailed deer (Odocoileus virginianus) populations is important because of the popularity of this species for sport hunting and the ecological and economic damage deer can cause. Managers traditionally have collected data from hunter-harvested deer to provide information for making these harvest management decisions. We tested for predictive relationships between these data and density using long-term (15–31 years duration, median = 26 years) harvest data for 9 populations in the southeastern United States that spanned several physiographic provinces and a wide range of densities (3–32 deer/km²) that varied by a factor of 1.67–5.50 within populations over the study period. Mean annual harvest for these populations ranged from 265–5,242 animals (median = 626). We tested 8 physical and 3 recruitment measures commonly collected on harvested deer for their relationship to reconstructed herd density estimates using correlation and linear regression models. Yearling male dressed body weights (range of average annual sample sizes: 53–260, median = 146) proved to be the parameter most consistently (7 of 9 populations) related to density (P < 0.05) among those tested. Yearling antler points (sample sizes the same as for yearling male weights) and yearling female dressed body weights (range of average annual sample sizes: 17–126, median = 72) also were related to density (P < 0.05). The most appropriate models were based on 2-year lags for density. Three-year running averages for both dependent and independent variables were used to smooth annual variability. Using data from 3 additional, independent populations validated that predicted and observed densities were highly correlated (r = 0.71–0.96; P < 0.01). The efficacy of time lags should serve to caution managers not to look for immediate responses in herds. The populations examined in this study provided long-term data that captured stochasticity resulting from density-independent factors. Despite any potential impact from these factors, we detected significant density-dependent relationships.     

梅花鹿(Cervus nippon hortulorum)茸角生长发育各阶段血浆睾酮、雌二醇的含量变化

本文用放射免疫测定法对3个不同年龄组的雄性东北梅花鹿茸角生长发育各阶段外周血中的睾酮、雌二醇含量进行了测定。茸期两种激素差异很大,睾酮含量低,雌二醇高,骨化期二者增高很快。对这两种激素含量的变化与茸角发育各阶段的关系进行了讨论。认为只有在二种激素同时增加时,鹿角才能骨化。     

Effects of selective harvest on antler size in white-tailed deer: A modeling approach

Selective harvesting in wild deer (Odocoileus spp.) populations is a common practice that may influence antler size. However, in free-ranging populations, response due to selection is unknown or difficult to quantify because antlers are influenced by nutrition and population demographics. We used quantitative genetic models to predict how white-tailed deer (O. virginianus) antlers would respond to selection and what variables (i.e., population size, age structure, mating ratio, and heritability) most affected antler size. We validated our quantitative genetics program by comparing model results with a population of deer used for controlled breeding experiments; modeled antler points (AP) and score increased (2.2–4.3 AP and 48.5–97.7 cm, respectively) after 8 years of selection, similar to observed increases in AP (3.2) and score (92.3 cm) from the controlled population. In modeled free-ranging populations, mating ratio, age structure, and heritability were more important in influencing antler size than size of the population. However, response to selection in free-ranging populations was lower (0.1–0.9 AP) than controlled breeding populations even after 20 years of selection. These results show that selective harvesting of free-ranging white-tailed deer may be inefficient to change population-level genetic characteristics related to antler size. Response of antlers in free-ranging deer will be less than controlled populations, and possibly modeled free-ranging simulations, because individual reproductive success of males is lower, breeding is done by a large group of males, and reproductive and survival rates are lower. These factors, and others, reduce the amount of improvement that can be made to antlers due to selection. Therefore, selective harvesting in free-ranging populations should be justified for managing population demographics and dynamics, but not for changing the genetic characteristics of populations. © 2011 The Wildlife Society.     

梅花鹿生长激素基因单核苷酸多态与产茸量性状的相关性

以梅花鹿的生长激素基因(GH)作为候选基因, 分析该基因对梅花鹿产茸量性状的影响。以吉林农业大学鹿场提供的梅花鹿为实验群体, 采用单链构象多态性(PCR-SSCP)和DNA测序的方法检测了GH基因单核苷酸多态性(SNPs), 针对该群体的特点建立合适的统计分析模型, 并进行了GH基因多态性与产茸量的相关分析。结果表明, GH基因对梅花鹿的产茸量有一定影响。G→A突变产生的3种基因型间的第五锯产茸量存在一定的差异(P<0.2), BB基因型个体在第五锯的产茸量与AA基因型个体之间有一定的差异(P<0.2)。     

光照因子对鹿茸生长发育的影响作用

控制光照周期中的光照强度(I)和光照／黑暗比率(L／D)对鹿茸的生长发育影响的作用明显,其中,在I=300lx和L/D=1.00-3.00时,鹿茸的生长发育最好。此外,鹿体内的性腺激素对鹿茸的生长发育有明显的作用。     

Major-histocompatibility-complex-associated variation in secondary sexual traits of white-tailed deer (Odocoileus virginianus): evidence for good-genes advertisement

Abstract Good-genes hypotheses predict that development of secondary sexual characters can be an honest advertisement of heritable male quality. We explored this hypothesis using a cervid model (adult, male white-tailed deer, Odocoileus virginianus ) to determine whether antler development could provide an honest signal of a male's genetic quality and condition to adversaries. We compared antler, morphometric, hormonal, and parasitic data collected from hunter-harvested deer to characteristics of the Mhc-DRB (Odvi) , the most widely studied gene of the major histocom-patibility complex (MHC) in Artiodactyla. We detected associations between genetic characteristics at Odvi-DRB and antler development and body mass, suggesting that antler development and body mass may be associated with pathogen resistance in deer and thus may be an honest signal of genetic quality. We also detected associations between Odvi-DRB characteristics and serum testosterone during the breeding season, suggesting that certain MHC characteristics may help deer cope with stresses related to breeding activity. In addition, we observed a negative relationship between degree of antler development and overall abundance of abomasal helminths. Our observations provide support for the hypothesis that antler development in white-tailed deer is an honest signal of quality.     

Seasonal changes in plasma leptin concentration related to antler cycle in Iberian red deer stags

The aim of this study is to describe the leptin cycle in male Iberian red deer (Cervus elaphus hispanicus) and relate it to antler and testosterone cycles. An additional aim is to assess the relationship between the plasma leptin concentration during antlers’ growth and their final size. Therefore, blood from 21 Iberian red deer males was sampled monthly to analyse leptin and testosterone. At the same time the deer were weighed and their body condition was assessed. The length of antlers was measured every 2 weeks and, after casting, their final length and perimeters were taken. Leptin showed a seasonal cycle, with a peak in June that decreased as testosterone increased. Low values were observed in autumn, winter and early spring. The relationship observed between leptin and body mass or body condition score was different in spring, when plasma testosterone concentration is low, than in autumn, when testosterone increases. Leptin peak amplitude was positively related to final antler size. In conclusion, the relationship between leptin and body mass and body condition score changes through the year, possibly due to the influence of androgens and photoperiod. There was a positive relationship between plasma concentration of leptin during antler growth and final antler length.     

Does Cu supplementation affect the mechanical and structural properties and mineral content of red deer antler bone tissue?

The main factors affecting the mechanical (and other) properties of bone, including antler, are the proportions of ash (especially Ca and P) and collagen content. However, some trace minerals may also play more important roles than would be expected, given their low levels in bone and antler. One such trace mineral is Cu. Here, we studied the effects of Cu supplementation on the mechanical and structural characteristics, and mineral content of antlers from yearling and adult (4 years of age) red deer fed a balanced diet. Deer (n=35) of different ages (21 yearlings and 14 adults) were studied. A total of 18 stags (11 yearlings and 7 adults) were injected with Cu (0.83 mg Cu/kg BW) every 42 days, whereas the remaining 17 (10 yearlings and 7 adults) were injected with physiological saline solution (control group). The Cu content of serum was analysed at the beginning of the trial and 84 days after the first injection to assess whether the injected Cu was mobilized in blood. Also, the mechanical and structural properties of antlers and the mineral content in their cortical walls were examined at three (yearlings) or four (adults) points along the antler beam. The effect of Cu supplementation was different in yearlings and adults. In yearlings, supplementation increased the Cu content of serum by 28%, but did not affect antler properties. However, in adults, Cu supplementation increased the Cu content of serum by 38% and tended to increase the cortical thickness of antlers (P=0.06). Therefore, we conclude that, even in animals receiving balanced diets, supplementation with Cu could increase antler cortical thickness in adult deer, although not in yearlings. This may improve the trophy value of antlers, as well as having potential implications for bones in elderly humans, should Cu supplementation have similar effects on bones as those observed in antlers.     

梅花鹿鹿茸不同产品中氨基酸含量的比较

通过对二杠鹿茸、三杈鹿茸、鹿茸片、鹿茸血、鹿角、鹿角盘等鹿茸产品中氨基酸含量的测定研究,结果表明:鹿茸血中氨基酸含量最高,鹿茸片中的氨基酸含量次之,三杈鹿茸中的氨基酸含量高于二杠鹿茸中氨基酸含量,鹿花盘中的含量高于鹿角中的氨基酸含量,从而为鹿茸这一动物性中药材资源的功能评价、药理作用提供科学理论依据。     

Getting the timing right: antler growth phenology and sexual selection in a wild red deer population

There has been growing interest in the determinants of the annual timing of biological phenomena, or phenology, in wild populations, but research on vertebrate taxa has primarily focused on the phenology of reproduction. We present here analyses of the phenology of the annual growth of a secondary sexual characteristic, antlers in red deer (Cervus elaphus) males. The long-term individual-based data from a wild population of red deer on the Isle of Rum, Scotland allow us to consider ecological factors influencing variation in the phenology of growth of antlers, and the implications of variation in antler growth phenology with respect to the phenotype of antler grown (antler mass) and annual breeding success. The phenology of antler growth was influenced by local environmental conditions: higher population density delayed both the start date (during spring) and the relative end date (in late summer) of antler growth, and warmer temperatures in the September and April prior to growth advanced start and end dates, respectively. Furthermore, there was variation between individuals in this phenotypic plasticity of start date, although not in that of end date of growth. The phenology of antler growth impacted on the morphology of antlers grown, with individuals who started and ended growth earliest having the heaviest antlers. The timing of antler growth phenology was associated with breeding success in the following mating season, independently of the mass of antlers grown: an earlier start of antler growth was associated with siring a higher number of the calves born the following spring. Our results suggest that the phenology of traits that are not directly correlated with offspring survival may also regularly show correlations with fitness.