Pedicle and antler fusion and double-head formation in a sika stag (<Emphasis Type="Italic">Cervus nippon</Emphasis>)

A case of pedicle and antler abnormality in a 12–14 year old sika stag shot in January 2003 in Schleswig-Holstein (Germany) is presented. The abnormality combines fusion of pedicles and antler bases with subsequent double-head formation. Double-heads result from growth of new antler bone without casting of the previous hard antlers. In consequence, two consecutively formed antlers are present in an individual. The stags skull showed a plate-like osseous structure whose broad and slightly elevated central portion was identified as the fused pedicles. The peripheral parts of this osseous plate constituted the second antler growth of the (former) double-head. A cast pair of antlers, which were fused at their bases, had been found in a neighbouring hunting district in the summer of 2002. The close fit between the casting surface of the fused antlers and the surface of the pedicle/antler structure on the stags skull indicated that the antlers had been grown by this stag and were belatedly cast from his fused pedicles. The fused antlers thus constituted the first antler growth of the double-head. We suppose that the broad connection between the fused antlers and the fused pedicles prevented antler casting at the normal time and thereby caused the double-head condition. The presentation of this antler abnormality is taken as an occasion to discuss the significance of pedicles for the normal casting and regeneration of antlers.     

Development and design of a novel loading device for the investigation of bone adaptation around immediately loaded dental implants using the reindeer antler as implant bed

The assessment of the behavior of immediately loaded dental implants using biomechanical methods is of particular importance. The primary goal of this investigation is to optimize the function of the implants to serve for immediate loading. Animal experiments on reindeer antlers as a novel animal model will serve for investigation of the bone remodeling processes in the implant bed. The main interest is directed towards the time and loading-dependant behavior of the antler tissue around the implants. The aim and scope of this work was to design an autonomous loading device that has the ability to load an inserted implant in the antler with predefined occlusal forces for predetermined time protocols. The mechanical part of the device can be attached to the antler and is capable of cyclically loading the implant with forces of up to 100 N. For the calibration and testing of the loading device a biomechanical measuring system has been used. The calibration curve shows a logarithmic relationship between force and motor current and is used to control the force on the implant. A first test on a cast reindeer antler was performed successfully.     

The induction of male sexual behavior in red deer (Cervus elaphus) by the administration of testosterone to hinds and estradiol-17β to stags

One-gram implants of testosterone were placed subcutaneously in two adult intact and one castrated red deer hinds, and 100-mg implants of estradiol-17β were given to three castrated and two intact red deer stags. Their sexual behavior was then observed in the wild and in captivity for up to 3 years. Testosterone initially produced prolonged and intense estrous behavior in the hinds; this gradually gave way to behavior normally shown only by rutting stags, such as flehmen, herding threats, and roaring. Testosterone-implanted hinds rose in the dominance hierarchy as measured by competition for food. Pregnancy, or the administration of progestagens, suppressed most of this testosterone-induced behavior. Testosterone also induced development of male secondary sexual characteristics such as formation of small antler pedicles (but not antlers), hypertrophy of the clitoris and neck musculature, and development of a neck mane and male rutting odor. Estradiol-17β mimicked the behavioral effects of testosterone when given to castrated stags, stimulating all components of rutting behavior. In intact stags, the only effects were to abolish antler casting and stimulate roaring; normal rutting behavior continued unchanged. In contrast to the effects of testosterone, estradiol-17β did not influence the social status of either intact or castrated stags. The distinctions between the behavioral effects of androgens and estrogens are ill defined and are determined more by the prior sexual differentiation of the brain and the duration of steroid treatment, than by the nature of the steroid.     

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。     

Antlers—a Mineral Source in Rangifer

In a calving area on western Hardangervidda, Norway, shed antlers of female reindeer, Rangifer tarandus tarandus L., have been collected for several years. Many of these antlers have been chewed on by reindeer. In the literature antler chewing has been reported to take place on both shed and unshed antlers. Our observations support these findings. Based on the present observations it is suggested that the antlers may subserve the mineral householding of the animals under special conditions. The female reindeer has to pass through a nutritionally marginal season which often coincides with calving. Bringing the bony antlers to the calving areas seems advantageous in the maintenance of calcium balance. The growth of antlers may therefore be looked upon as part of a mineral saving strategy. The mineral stored in the antler thus represents a reserve to be used during pregnancy and lactation. This is in contrast to the common view that shedding of antlers is just waste of mineral when there is a great need for calcium.     

Induction of antler growth in a congenitally polled Scottish red deer stag.

A congenitally polled red deer stag was captured from a Scottish deer forest and kept in an enclosure for observations. The animal had rudimentary antler pedicles but no antlers, and during five years of study no significant antler development occurred. Amputation of the apex of one antler pedicle in May 1974 when the stat was 12 years of age resulted in the growth of a complete antler on the operated side, and this antler was subsequently cleaned and cast in the normal way and a new antler cycle was initiated. The result illustrates that the primary abnormality in this polled stag lay not in his inability to grow antler, but in his inability to develop fully formed antler pedicles from which normal antler tissue could differentiate. Traumatizing the rudimentary pedicle had the effect of stimulating growth of antler tissue, and once this was formed the process of cleaning, casting and regrowth occurred spontaneously. The incomplete development of the antler pedicles is considered to be responsible for the absence of antlers in the majority of "hummels" in Scotland, and the etiology of the condition is discussed.     

Effect of antiandrogen cyproterone acetate on the development of the antler cycle in Southern pudu (Pudu puda)

The antler cycle of pudu is similar to other cervids, but unlike most boreal deer, male Southern pudu (Pudu puda) exhibits two seasonal peaks of LH and testosterone. In that respect, pudu is similar to roe deer. Whereas the antler cycle in some deer species, such as roe deer or white-tailed deer, is very sensitive to variation of testosterone, in other cervids, such as fallow deer or reindeer, a blockade of androgens with cyproterone acetate (CA) has little or no effect on the timing of the antler casting. In order to test the sensitivity of pudu antlers to variations of androgens, CA (administered 2x weekly at 50 mg/buck) was injected intramuscularly for 3 weeks in 5 adult male pudu, starting February 19 (late summer). Four other males of similar age served as controls. The experiment was performed at the University of Concepcion, Chile, latitude 36.6 degreeS. Blood samples were taken once a week between January 19 and April 3. In CA-treated bucks, the antlers were cast approximately 3 weeks after the initiation of CA treatment and a new antler growth began almost immediately. The antlers reached about 5 cm in length, before ceasing to grow at the end of April, when they became mineralized and were subsequently polished. CA had no effect on the already declining levels of LH. Plasma levels of testosterone in controls increased from February 15, whereas in CA-treated bucks remained depresses until March 21. It is concluded that similarly to white-tailed deer, the antler cycle of Southern pudu is very sensitive to manipulation of androgen levels.     

Annual variations in fecal androgen metabolites and antler cycle of captive red brocket bucks (<Emphasis Type="Italic">Mazama americana</Emphasis>) in southeast Brazil

Annual variations in fecal androgen metabolites (FAM) and antler cycle were analyzed in six red brocket bucks exposed to a natural photoperiod in southeast Brazil. Fecal samples and antlers status data were collected weekly during a 1-year period. Four animals were in hard antler throughout the year, whereas one individual cast antlers in September and other took several months to completely shed antler velvet. Monthly means (±SEM) of FAM concentrations exhibited no differences in all monitored bucks (P > 0.05). In addition, FAM levels from four males that kept hard antlers year-round were grouped by month and no differences among monthly means were found (P > 0.05). Comparisons between FAM levels at different antler stages were not possible because of the low number of males presenting changes in antler status. These findings indicate that red brocket bucks present no annual pattern in androgen secretion and antler changes, suggesting that testicular and antler cycles in this species are little or not affected by photoperiodic cues.     

Internal architecture of pampas deer antlers differs in males allocated with and without females

Bone mineralization of antlers and the depth of the antler seal (the basal surface of the cast antlers) are positively related to testosterone concentrations. Pampas deer males that are in permanent contact with females have greater, heavier, and darker antlers than males that are isolated from them. The objectives were to determine if antler compact/spongy bone ratio, antler seal depth, and compact bone darkness are greater in pampas deer males permanently allocated with females than those in males isolated from them. Antlers from males permanently allocated with or without females were cut transversally in seven points and scanned, and the compact/spongy ratio was calculated. The pixel intensity of each image was determined with a software for image analysis. The coronet of the antler was cut longitudinally, and the height of the most prominent protrusion was measured. The compact/spongy ratio was greater in antlers from males that were in contact with females in the second tine (P?=?0.02) and tended to be great in the two other tines (P?=?0.06 and P?=?0.1, respectively). Compact bone pixel color was darker in males in contact with females than that in males isolated from females in two points (P?=?0.02 and P?=?0.05, respectively) and tended to do so in two more (P?=?0.055 and P?=?0.1, respectively). Antler seal convexity was also greater in antlers from males in contact with females (P?=?0.006). We concluded that permanent contact with females stimulated pampas deer males increasing compact bone portion of the antler tines, the seal depth size, and the darkness of the compact bone.     

The effect of cyproterone acetate on the antler cycle in red deer (Cervus elaphus L.)

The aim of the study was to test the effect of antiandrogen, cyproterone acetate (CA) on the antler cycle in the red deer (Cervus elaphus). CA was administered to three adult red deer stags (Edward, Fuks and Gacek) in weekly intervals. Edward and Fuks were given 600 mg + 600 mg of CA, whereas Gacek was given 600 mg + 300 mg. CA was injected during the hard antler phase: in mid-October (Edward), at the end of November (Fuks) and at the end of January (Gacek). CA caused the antler casting 17 to 22 days after the first injection. In all stags, the casting of antlers was followed by a period of intensive growth of new antlers. Edward was given CA at the end of October. This treatment was responsible for occurrence of the two antler cycles in the year of the experiment. When CA was administered during the middle of the hard antler phase an additional short antler cycle occurs followed by new antler growth. CA treatment in the later part of hard antler phase may cause a prolonged antler cycle.     

Age-related changes in the testicular and antler cycles of reindeer, Rangifer tarandus

A total of 111 male reindeer of various ages was shot in all months of the year to study the relationship between the seasonal changes in testicular activity and the antler cycle. From the changes in testis weight, seminiferous tubular tissue area and plasma testosterone values and the occurrence of spermatogenesis, it is concluded that calves attain physiological puberty in their first year, during which they also complete an antler cycle. The amplitude of the cyclical change in testis weight and plasma testosterone values increases with age and can be correlated with the earlier onset of events in the spermatogenic and antler cycles of older animals. The duration of the spermatogenic and testosterone cycles of reindeer is short, and is inversely related to the long period spent without antlers. It is suggested that testosterone strongly influences the antler cycle of reindeer males.     

Territory Establishment and Antler Cycle in Male Roe Deer

Territory establishment and antler cycle in male roe deer, Capreolus capreolus, were studied in two areas in south-eastern Sweden during 1989–1993. Initial territorial behaviour was observed in early Mar., when overlap between male ranges decreased from 66 % to 0 % over a 3–6-wk period, as determined from telemetry data. The decrease was associated with an increased number of agonistic interactions. Most territories were established at the end of Mar. to early Apr., with a tendency for males re-establishing old territories to be first. In all years, territories were taken up 1–3 wk before males shed velvet from their antlers. The distance between geometric centres of neighbouring males in winter and after territory establishment increased from 164 to 364 m. Former territory holders moved the geometric centres of their winter range and subsequent territory a shorter distance than first-year territorials, 129 and 267 m respectively. Territory defence ceased after the rut in late Aug., and the spatial relations between neighbours reverted to the situation before the territorial season. Neither velvet shedding nor antler casting was correlated with male age (yearlings excluded), which contradicts earlier statements. Neither were there any associations between timing of antler casting and subsequent velvet shedding, nor vice versa. Hence, a male casting antlers early one year derives no advantage by early shedding the next season. Furthermore, to be in hard antlers is not a prerequisite for territory take-up, whereas antlers probably are necessary for maintaining the area throughout the season. Functional aspects on roe buck territoriality are also discussed.     

Antlers and parasites

Development of ornamental characters exposed to directional selection may be particularly sensitive to the effect of parasitic infections. Antlers are ornamental characters of importance in intraspecific interactions, and are in reindeer (Rangifer) developed by both males and females. By antihelmintic treatment of naturally infected female reindeer we show that parasite intensities affect development of antler asymmetry, but not antler length. These results suggest that asymmetry in antlers may reflect parasite intensities and thus be of importance in intraspecific assessment of genetic resistance towards infectious organisms.     

The effect of artificial photoperiodicity and antiandrogen treatment on the antler growth and plasma levels of LH, FSH, testosterone, prolactin and alkaline phosphatase in the male white-tailed deer

1. Artificial extension of day-length in adult male white-tailed deer during the autumn induced: (a) premature casting of antlers, early onset of the new antler growth and out of season mineralization, (b) early elevation of plasma levels of prolactin, LH, FSH, testosterone and alkaline phosphatase and (c) out of season hair molt. 2. Intramuscular administration of the antiandrogen cyproterone acetate immediately after velvet shedding induced: (a) dramatic reduction of testosterone levels in plasma, (b) premature casting in bucks with fully mineralized antlers and (c) renewal of bone rebuilding activity in incompletely mineralized antlers which resulted in blockage of casting.     

Influence of photoperiod on the seasonal pattern of secretion of luteinizing hormone and testosterone and on the antler cycle in roe deer (Capreolus capreolus).

Annual variations in concentrations of luteinizing hormone (LH) and testosterone in plasma were analysed in relation to the antler cycle in six adult male roe deer exposed to a natural photoperiod (latitude 46 degrees 10'N) and in four adult males maintained in a constant short-day photoperiod (8 h light: 16 h dark) for a year, from the winter solstice at which time both groups of animals had antlers in velvet. The animals were sampled, every 15 min for 2 or 4 h at intervals of one month for a year. Under both natural and experimental conditions, LH concentrations were high from January to March, but in the experimental conditions they decreased between April and May-June, whereas in the natural conditions they increased. Plasma LH concentration was lowest between July and November in animals under natural photoperiod, whereas under 8 h light:16 h dark photoperiod a second increase in plasma LH occurred between August and September. Between March and August, concentrations of plasma testosterone increased under natural photoperiod, whereas under experimental photoperiod there was a biphasic pattern of plasma testosterone with peaks between February and May and between September and November. Under natural photoperiod, antlers were cast in November, 369 +/- 6 days after the previous antlers were cast. Under experimental photoperiod, antlers were cast after 193 +/- 10 days, and a new set developed. The sexual cycle of the male appears to be initiated by an endogenous rhythm in winter and is then maintained by hormonal changes resulting from increasing photoperiod in spring.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of environmental conditions, human activity, reproduction, antler cycle and grouping on fecal glucocorticoids of free-ranging Pampas deer stags (Ozotoceros bezoarticus bezoarticus)

In this study, a commercial enzyme immunoassay (EIA) was validated in detecting glucocorticoids in Pampas deer feces, in order to investigate the influence of several factors on the adrenocortical function. Fecal samples, behavioral data and information concerning male grouping and antlers status were collected at a monthly basis during a 1 year period from free-ranging stags living at Emas National Park, Brazil (18 degrees S/52 degrees W). The results revealed that concentrations of fecal glucocorticoids in winter were significantly higher than those corresponding to spring and summer. In addition, dry season data presented higher levels than during the wet season. Significant difference was found between fecal levels of breeding stags in summer and nonbreeding stags, whereas no difference was observed between breeding stags in winter and nonbreeding stags. On the other hand, males from areas with frequent human disturbance exhibited higher glucocorticoid concentrations and flight distances than individuals from areas of lower human activity. Males with antlers in velvet had elevated levels compared with animals in hard antler or antler casting. Also, we found that glucocorticoid levels were higher in groups with three or more males than in groups with only one male. The flight distances showed positive correlation with fecal glucocorticoid. These data indicate that fecal glucocorticoid provides a useful approach in the evaluation of physiological effects of environment, inter-individuals relationship and human-induced stressors on free-ranging Pampas deer stags.     

Sexual dimorphism in the pelvic bones of Svalbard reindeer, Rangifer tarandus platyrhynchus

The determination of sex of carcasses of reindeer and caribou (Rangifer tarandus) is complicated because both sexes normally carry antlers. Growth curves of males and females diverge sufficiently so that the length of long bones can often indicate the sex of a carcass if its age at death is known; results, however, are not always conclusive. Pronounced sexual dimorphism was found in the breadth of the ventro-medial border (rim) of the acetabulum of adult Svalbard reindeer. Measurement of the rim of the acetabulum thus provides a quick and conclusive means for determining the sex of carcasses of these animals. Similar results have been found in several other species of ungulates. Reasons for the dimorphism and for the non-normal distribution of the data for both sexes in reindeer are discussed.     

Gender differences in steroid modulation of angiotensin II-induced protein kinase C activity in anterior pituitary of the rat

To investigate whether the various steroid hormones can modulate the basal and angiotensin II-induced protein kinase C (PKC) activity in the anterior pituitary of the rat, female and male intact and ovariectomized female Wistar rats were treated in vivo with estradiol (E2), progesterone (P), dehydroepiandrostendione sulfate (DHEA-S), and pregnenolone sulfate (PREG-S). Estradiol caused the increase of basal PKC activity in intact and ovariectomized females, but did not change the enzyme activity in males. In ovariectomized animals the increase of PKC activity was lower than in intact females. Progesterone decreased PKC activity only in intact animals. DHEA-S strongly enhanced activity of PKC in ovariectomized females. Pregnenolone sulfate did not significantly change PKC function of all studied groups. Incubation with AngII enhanced the PKC activity in intact (without steroid treatment) animals of both genders. In females, AngII and estradiol together rise the PKC-stimulated phosphorylation in greater degree than used separately. Treatment with other investigated steroids reduced the effect of AngII. In intact males every examined hormone turned back the stimulatory effect of AngII on PKC activity. These data suggest that gender differences in PKC activity are likely related to hormonal milieu of experimental animals and may depend in part on the basic plasma level of estrogens.     

The asynchronous timing of antler casting of Reeves’ muntjac (Muntiacus reevesi)

From 1973 until the present time, captive Reeves’ muntjac (Muntiacus reevesi) have been observed in England. The dates of casting of both antlers have been recorded for 25 bucks, totalling 121 antler cycles. All casting dates were between 1 May and 17 July (63.64 % of the cycles occurred in May, 34.71 % in June, and only 1.65 % in July). Only 13.2 % of the antler cycles were synchronous. In 45.71 % of cases, the left antler was cast 1 day or more before the right one, whereas in 54.29 % of cases, the reverse was true. For 57.14 % of cases, the time between castings of the first and second antlers was up to 3 days, and for 32.38 % of the cases, the interval was 4 to 8 days, and in 10.48 %, the difference was 9 to 13 days. All bucks cast their antlers asynchronously at least in some of the antler cycles. No external factor, which would be responsible for this, was detected. Significant variation across season has been shown with no apparent trend. Although records on subsequent seasons were available for most of the bucks, there was a zero repeatability of the process.     

Remains of Late Pleistocene reindeer from Chmielewo,northeast Poland

Reindeer (Rangifer tarandus L.) remains in Europe are well represented in Late Pleistocene sites in France, Germany, Ukraine, Poland and other countries. In a chalk mine at Chmielewo (near niardwy Lake, NE Poland) four antlers were recovered. Radiocarbon assays date the fossils to the end of the Pleistocene. All antlers belong to male reindeer. One of the discovered specimens is an uncast antler of the tundra reindeer form, while the others are of the woodland reindeer form. The uncast antler has distinctly visible parieto-frontal fixation of the beam to the skull that confirms its parallel position in relation to the ground.