Rutting Period Research Articles

Rutting calls of harem‐holders, harem‐candidates and peripheral male Siberian wapiti Cervus canadensis sibiricus: Acoustic correlates of stag quality and individual identity

AbstractThis study investigates the effects of individuality and harem‐holding status on the acoustic parameters of rutting calls (bugles) of 14 stags of Siberian wapiti Cervus canadensis sibiricus. The stags competed for mating with hinds in a large herd, free ranging inside a fenced area with complex landscape. We considered as harem‐holders the stags, which kept a harem of 5 or more hinds for at least 2 days. Of the 15 days of observations enveloping the most active rutting period, during 3 days there was only one harem in the enclosure, during 9 days two harems, during 2 days three harems and during 1 day four harems. Stag bugles displayed both individual and status‐related variation. Harem‐holders compared with peripheral stags had shorter bugles with higher minimum fundamental frequency. After winning a harem and changing status from harem‐candidate to harem‐holder, stags shortened the duration of their bugles, lowered the beginning and maximum fundamental frequency and increased the minimum fundamental frequency. Significantly higher than the levels expected by chance, discriminant analysis classified 78.9% of bugles by the correct stag status and 53.2% of bugles by the correct individual callers. Different acoustic parameters encoded the status and individuality of the bugles. Status was encoded by the duration of the start and end parts and by the beginning and end fundamental frequencies. Individuality was encoded by the maximum fundamental frequency. We discuss that rutting calls of Siberian wapiti, although individualized, do not represent vocal signatures. However, these calls reliably mark stag harem‐holding status.

Modelling reindeer rut activity using on-animal acoustic recorders and machine learning.

For decades, researchers have employed sound to study the biology of wildlife, with the aim to better understand their ecology and behaviour. By utilizing on-animal recorders to capture audio from freely moving animals, scientists can decipher the vocalizations and glean insights into their behaviour and ecosystem dynamics through advanced signal processing. However, the laborious task of sorting through extensive audio recordings has been a major bottleneck. To expedite this process, researchers have turned to machine learning techniques, specifically neural networks, to streamline the analysis of data. Nevertheless, much of the existing research has focused predominantly on stationary recording devices, overlooking the potential benefits of employing on-animal recorders in conjunction with machine learning. To showcase the synergy of on-animal recorders and machine learning, we conducted a study at the Kutuharju research station in Kaamanen, Finland, where the vocalizations of rutting reindeer were recorded during their mating season. By attaching recorders to seven male reindeer during the rutting periods of 2019 and 2020, we trained convolutional neural networks to distinguish reindeer grunts with a 95% accuracy rate. This high level of accuracy allowed us to examine the reindeers' grunting behaviour, revealing patterns indicating that older, heavier males vocalized more compared to their younger, lighter counterparts. The success of this study underscores the potential of on-animal acoustic recorders coupled with machine learning techniques as powerful tools for wildlife research, hinting at their broader applications with further advancement and optimization.

Влияние сроков щенения на воспроизводительные качества лисиц породного типа «Савватьевский»

The article presents the results of the analysis of the dynamics of the timing of the pupping of silver-black foxes during the creation of the breed type "Savvatievsky". The optimal timing of female coverage has been identified. The timing of the pupping of females of different degrees of blood is analyzed. A comprehensive analysis of the effect of the timing of puppies on the fertility of females and the output of puppies to the main female was carried out. Based on the conducted research, the following conclusions can be drawn: the puppies of domestic breeding females occur mainly in April (53.1 %). Breeders of the farm, in an effort to consolidate in a new breed type of foxes such economically useful signs as the large size and quality of the hair cover characteristic of foxes of the Norwegian type, annually selected males and females phenotypically satisfying the task, this led to an increase in the percentage of unfavorably giving birth, procreating and missing females by 2021. In order to change the situation and increase reproduction rates, it is necessary to select females for a tribe whose rutting period begins in the month of February, since this category of females revealed a minimum percentage of those who missed, got sick and gave birth unfavorably, and in addition, high fertility rates and the percentage of preservation of young.

Effect of mineral-vitamin premix supplementation on behavioral, performance, hormonal, oxidative stress, and serum biochemical profiles on rutting male Camelus dromedarius in Egypt.

The rutting period imposes a stressful condition on male camels, which results in elevated serum cortisol levels and alterations in their sexual behavior. Therefore, the current work was carried out to investigate the effect of mineral-vitamin premix supplementation on behavior, reproductive performance, hormones, serum oxidative stress profile, and other serum biochemical parameters of Camelus dromedarius during the breeding season. Fourteen mature, fertile male Camelus dromedarius were divided into two groups, a control group (n = 7) and a mineral-vitamin premix group (n = 7). The present study lasted for 95 days during the rutting period (1st February to 5th May). Each camel in the premix group received a daily diet of 50 g of mineral-vitamin premix throughout the whole rutting period, during which the frequencies and durations of the following behaviors: maintenance, posture, aggressiveness, and sexual activity were collected every 20 min. At the end of the study, blood samples were collected. Results revealed that the premix group showed higher (P < 0.05) maintenance (feeding and rumination), standing, and overall sexual desire-related behavior frequency, besides more times (P < 0.001) for rumination, standing, walking, and lying while showing lower (P < 0.001) frequencies of overall aggressive behaviors than the control group. The serum concentration of malondialdehyde, nitric oxide, cortisol, blood glucose, and urea evidenced a significant decrease in the premix group compared with the control one, while significantly elevated levels of reduced glutathione, testosterone, total antioxidant capacity, triiodothyronine, and thyroxin, total protein, albumin, globulin, calcium, phosphorus, potassium, and magnesium were recorded in the premix group in comparison with the control. It could be concluded that daily dietary supplementation of 50 g of mineral-vitamin premix to male camels during the breeding season is necessary to overcome the oxidative stress and serum cortisol concentration with a subsequent decrease in aggressive behavior and improvement to testosterone level in blood, body condition score and body weight gain.

Bone resorption and formation in the pedicles of European roe deer (Capreolus capreolus) in relation to the antler cycle-A morphological and microanalytical study.

We analyzed pedicle bone from roe bucks that had died around antler casting or shortly before or during the rutting period. Pedicles obtained around antler casting were highly porous and showed signs of intense osteoclastic activity that had caused the formation of an abscission line. Following the detachment of the antler plus a portion of pedicle bone, osteoclastic activity in the pedicles continued for some time, and new bone was deposited onto the separation plane of the pedicle stump, leading to partial pedicle restoration. Pedicles obtained around the rutting period were compact structures. The newly formed, often very large secondary osteons, which had filled the resorption cavities, exhibited a lower mineral density than the persisting older bone. The middle zones of the lamellar infilling frequently showed hypomineralized lamellae and enlarged osteocyte lacunae. This indicates a deficiency in mineral elements during the formation of these zones that occurred along with peak antler mineralization. We suggest that growing antlers and compacting pedicles compete for mineral elements, with the rapidly growing antlers being the more effective sinks. The competition between the two simultaneously mineralizing structures is probably more severe in Capreolus capreolus than in other cervids. This is because roe bucks regrow their antlers during late autumn and winter, a period of limited food and associated mineral supply. The pedicle is a heavily remodeled bone structure with distinct seasonal variation in porosity. Pedicle remodeling differs in several aspects from the normal bone remodeling process in the mammalian skeleton.

Pre-rut behavioural changes in farmed red deer with reference to atmospheric conditions

Red deer (Cervus elaphus) exhibit specific behaviour during the rutting season, which may have an impact on the safety on cervid farms, both due to aggressive interactions between animals and the safety of people staying there, such as staff and tourists. This issue applies especially to stags whose behaviour changes radically, and the correct interpretation of the observed changes is very important. Therefore, the aim of the study was to analyse the pre-rut behaviour of stags and to show the influence of atmospheric conditions on vocalization and other elements of their behaviour, which facilitate determination of the onset of the rutting season. The observations were conducted in August and September of 2017 and 2018. It was shown that lower temperatures, declines in air humidity, increasing atmospheric pressure, and transition of the moon phase towards the full moon resulted in intensification of the vocalization activity in the red deer in the pre-rutting season, which may accelerate the rutting period in the deer males. The number of vocalizations varied between the years and depended on the mean temperature, air humidity, atmospheric pressure, and moon phase in the prerutting and rutting seasons. Through observation of the changing weather conditions, it is possible to predict the time of increased activity of stags and the onset of the rutting period. Predicting the date of mating season in farm breeding, based on daily observations of changes in the behaviour of stags, can be helpful in planning veterinary treatments or selecting the composition of the hinds to be covered by specific stags, which can also contribute to the improvement of their welfare.

Nocturnal chats of farmed animals: non-rutting vocalisations of male Iberian red deer, Cervus elaphus hispanicus

Context Captive environment may inhibit the emission of some call types by non-domesticated farm and zoo animals; so, their complete vocal repertoires remain unknown. Automated acoustic recording might help fill this gap of knowledge. Aim The aim of this study was to describe vocalisations of farmed Iberian red deer, Cervus elaphus hispanicus, stags out of the autumnal rutting period (in summer and in winter) applying the manual and automated acoustic recording. Methods In this pilot study, automated audio recording of undisturbed animals followed with spectrographic analysis showed hidden parts of social acoustic communication in farmed male Iberian red deer in non-breeding period. Key results We detected three call types (roars, contact calls and bellows). Stag contact calls and bellows were described in the first time in red deer. Non-rutting roars were acoustically similar with rutting roars reported for wild-living Iberian red deer stags but of lower-frequency than were stag rutting roars recorded on the same farm in previous studies. Stag contact calls were reminiscent of hind contact calls recorded on the same farm in previous studies, but lower in frequency and shorter. Stag bellows were acoustically similar with bellows of male domestic cattle. Conclusion This study reveals previously unknown parts of male red deer vocal repertoire. Implications The lack of certain components of behavioural and vocal repertoire may indicate potential welfare problems in farmed and zoo animals.

Seasonal variation in testicular biometry of wild boar in the game preserve

The increase in wild boar numbers in recent decades is partly due to the involvement of most young females in reproduction as early as their first year of life. After the rut of adult females is over, young females are still entering oestrous as they attain maturity, prolonging the rutting period by several months. This study aimed to evaluate the effect of seasonality on the growth rate of male wild boar bodies, the growth of piglet and yearling male wild boar gonads, and sperm concentration in the epididymides. We found that yearlings' weight and body length were almost constant in summer and autumn, with a sharp increase in winter. Seasonality was also reflected in the body condition index, which rose by more than 41% between summer and winter. In terms of seasonality, the testimetric dimensions again differed significantly only in winter. Sperm were recorded in piglets weighing more than 15 kg. Regardless of the time of capture, 41% of piglets were examined as juveniles, only 6%, resp. 8% of piglets reached low or medium concentration values. While 10% of all yearling males were azoospermatic (juvenile), regardless of weight, there was evidence of seasonality in the proportion of males with measurable concentrations. These concentrations gradually increased from 62.5% in summer to 78.6% in winter. No sterile male over two years of age was noted. The results show that even in wild boars, there is a culmination not only of physical characteristics in winter but also a culmination of testimetric dimensions. Sperm already occur in 15 kg of piglets, which means they can theoretically participate in the fertilisation of female piglets.

Towards Automated Detection and Localization of Red Deer Cervus elaphus Using Passive Acoustic Sensors during the Rut

Passive acoustic sensors have the potential to become a valuable complementary component in red deer Cervus elaphus monitoring providing deeper insight into the behavior of stags during the rutting period. Automation of data acquisition and processing is crucial for adaptation and wider uptake of acoustic monitoring. Therefore, an automated data processing workflow concept for red deer call detection and localization was proposed and demonstrated. The unique dataset of red deer calls during the rut in September 2021 was collected with four GPS time-synchronized microphones. Five supervised machine learning algorithms were tested and compared for the detection of red deer rutting calls where the support-vector-machine-based approach demonstrated the best performance of −96.46% detection accuracy. For sound source location, a hyperbolic localization approach was applied. A novel approach based on cross-correlation and spectral feature similarity was proposed for sound delay assessment in multiple microphones resulting in the median localization error of 16 m, thus providing a solution for automated sound source localization—the main challenge in the automation of the data processing workflow. The automated approach outperformed manual sound delay assessment by a human expert where the median localization error was 43 m. Artificial sound records with a known location in the pilot territory were used for localization performance testing.

"Move or Not to Move"-Red Deer Stags Movement Activity during the Rut.

Simple SummaryThe spatial and temporal structure of the movement of animals is based on behavioural decisions that promote evolutionary success. One of these behavioural decisions is mating strategy. In this paper, we examined the relationship between the movement activity of red deer stags and the fertile period of hinds. We hypothesized that the oestrus of hinds significantly affected the daily activity of stags. We determined the oestrus period of hinds, which was compared with the movement data of the stags determined by GPS telemetry. The combination of GPS telemetry data and oestrus data for red deer has never been used in parallel to demonstrate how the reproductive activity of females affects the spatial behaviour of males in red deer. Knowledge of the movement behaviour of red deer during the mating season is important information in both nature conservation and game management.Detailed animal movement analysis can help understand spatial population processes as the ultimate consequences of individual behaviour and ecological impacts. The mating strategy of mammalian herbivores is adapted to the distribution of females; thus, it is important to observe the activity of animals during a rut. In this paper, we used a new approach to examine the relationship between red deer stags’ movement activity and the fertile period of hinds. We presumed a relationship between stags’ daily activity changes and the period when hinds are in heat. We determined temporal conception trends, including the first and last conception dates in the examined population and the conception peak. In the same period, i.e., in the interval of major ecological significance when mating takes place, the activity of stags was analysed by GPS telemetry. The data collected in the examined period indicate that 60% of the hinds were conceived between 31 August and 19 September. We demonstrated that conception rates differed significantly between the first and second half of the rutting period. At the beginning of the reproductive cycle, the high number of hinds on heat (oestrus synchrony) increased the activity of stags (harem herding) compared to the pre-rutting period. As the mating season progressed, the movement activity of stags increased more (searching behaviour), induced by the decreasing number of fertile hinds. Therefore, we found that the oestrus of hinds significantly influenced the movement activity of stags in red deer.

Male impala (Aepyceros melampus) vocal activity throughout the rutting period in Namibia: daily and hourly patterns

The data supporting the findings of this study are available from the corresponding author upon reasonable request. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Testicular Melatonin and Its Pathway in Roe Deer Bucks (Capreolus capreolus) during Pre- and Post-Rut Periods: Correlation with Testicular Involution.

Roe deer are seasonal breeders with a complete yearly testicular cycle. The peak in reproductive activity is recorded during summer, the rutting period, with the highest levels of androgens and testicular weight. Melatonin plays a pivotal role in seasonal breeders by stimulating the hypothalamus-pituitary-gonads axis and acting locally; in different species, its synthesis within testes has been reported. The aim of this study was to evaluate the physiological melatonin pattern within roe deer testes by comparing data obtained from animals sampled during pre- and post-rut periods. Melatonin was quantified in testicular parenchyma, along with the genetic expression of enzymes involved in its local synthesis (AANAT and ASMT) and function (UCP1). Melatonin receptors, MT1-2, were quantified both at protein and gene expression levels. Finally, to assess changes in reproductive hormonal profiles, testicular dehydroepiandrosterone (DHEA) was quantified and used for a correlation analysis. Melatonin and AANAT were detected in all samples, without significant differences between pre- and post-rut periods. Despite DHEA levels confirming testicular involution during the post-rut period, no correlations appeared between such involution and melatonin pathways. This study represents the first report regarding melatonin synthesis in roe deer testes, opening the way for future prospective studies in the physiology of this species.

Slow and ultra-rapid freezing protocols for cryopreserving roe deer (Capreolus capreolus) epididymal sperm collected at different times of year

The roe deer is a monoestrous species with a very short rutting season. The present work reports the most suitable period for collecting epididymal sperm and describes the effect of two cooling rates on the post-thaw quality of sperm. Testes were collected 24–48 h after death. Samples of sperm flushed from the epididymis were subjected to either (1) dilution in a Tris-citric acid-glucose-egg yolk-based medium with glycerol, and slow freezing in straws, or (2) dilution in the same extender but replacing the glycerol with 100 mM of sucrose, and ultra-rapid freezing in pellets. Sperm motility, acrosome and membrane integrity, morphometry and morphological abnormalities were analysed before and after cryopreservation. Spermatogenic activity was investigated via histological examination of testis sections. Several testes collected between April, May and September showed no spermatogenic activity. All those collected in June–August showed spermatogenic activity. No significant difference was detected in the cryoresistance ratios associated with the conventional slow freezing, between sperm collected during the pre-rutting (April–May) and rutting (June–August) periods. No significant differences were seen between the slow-frozen-thawed and the ultra-rapid-frozen-thawed sperm in terms of percentage of viable sperm or the percentage of sperm with morphological abnormalities. Slow freezing returned significantly better (P<0.05) values for post-thaw acrosome integrity (43.3% vs. 25.0%) and straight-line velocity (19 μm/s vs. 4 μm/s). For both freezing methods, sperm heads were smaller post-thawing than pre-freezing (P<0.001). In conclusion, both the pre-rutting and rutting season are suitable periods for freezing roe deer sperm. Ultra-rapid freezing did not provide suitable results.

Intrinsic factors, release conditions and presence of conspecifics affect post‐release dispersal after translocation of Iberian ibex

AbstractTranslocation is an important tool in restoring biodiversity, particularly when species have been extirpated from an area. In the period just after release, the main objective of conservation managers is to keep as many of the translocated individuals in the release area as possible, in order to maximize the number of founders of the new population. Environmental and intrinsic factors, release conditions and social behaviour are likely to influence an individual’s propensity to move away from the release site (known as post‐release dispersal); however, few studies have explored the relative importance of these factors. The aim of this study was to evaluate how these four factors affected the post‐release dispersal of 169 Iberian ibex translocated from Spain to the French Pyrenees. We modelled the linear distance between the barycentre of each individual ibex’s monthly locations and the release site. Our results indicated that most individuals stayed close to the release site, but that inter‐individual variability was high. Post‐release dispersal was higher for males than females, with male breeders exhibiting higher exploration behaviour than juveniles. Release season played a major role, with dispersal being the lowest in spring and the highest during the rutting period. Dispersal was also found to be lower when conspecifics were present in the release area, probably due to their role as a cue for favourable habitat. These findings can be used by conservation managers to inform translocation strategies in order to enhance success: for example by releasing females and young males in spring and splitting a reintroduction project into successive release operations.

Do reproductive constraints or experience drive age-dependent space use in two large herbivores?

Life histories are strongly age dependent, notably linked to the onset of reproductive maturity and subsequent senescence. Consequently, ageing is predicted to impact behaviour, through the expression of either mating tactics in males or neonatal antipredator tactics in females. However, the influence of ageing, and the associated reproductive activity, on spatial behaviour remains poorly investigated. In this regard, we quantified age- and sex-specific intra-annual variation in movement rates and space use of two large herbivores with contrasting life histories: the roe deer, Capreolus capreolus, an asocial species with a territorial male mating strategy and a hider neonatal tactic, and the Mediterranean mouflon, Ovis gmelini musimon × Ovis sp., a gregarious species with a roaming male mating strategy and a follower neonatal tactic. We expected age-related differences to be mostly related to (1) age-specific mating tactics during the rut for males and the presence/absence of offspring for females, and (2) experience and/or locomotory senescence otherwise. During the rutting period, older roe deer males travelled greater daily distances than younger males due to patrolling behaviours for territory defence, whereas older mouflon males travelled less than younger males, which often adopted coursing tactics to mate with females. During the birth period, reproductive females had smaller home ranges than nonreproductive females in roe deer, whereas no marked differences were observed in mouflon females. The most marked age-related variation in space use of mouflon occurred outside the reproductive periods; specifically, the oldest individuals travelled less far and had a smaller home range (females only) than younger individuals. Our findings illustrate how space use tactics vary within and between populations of large herbivores, providing strong evidence that age and reproductive activity are major determinants of their spatial behaviour.

Morphological and histochemical changes in the dromedary camel epididymis in relation to reproductive activity.

Environmental conditions such as temperature, light and food availability are known to influence the physiological status of animals. The male dromedary camel (Camelus dromedarius) is considered as a seasonal breeder with maximal sexual activity during certain period of the year followed by a decrease in activity during the remaining period. On the other hand, the male camel is also shown as an atypical seasonal breeder because this does not undergo sexual quiescence with complete cessation of spermatogenesis. This animal, however, shows remarkable physiological and behavioral changes during its maximal sexual activity. The annual breeding (rutting) period also influences the epididymis. In this review, an attempt has been made to present the available literature pertaining to gross anatomical, histological, histochemical, immunohistochemical and molecular changes in camel epididymis during breeding and nonbreeding periods, and the changes are believed to be correlated with male sexual behavior and libido. This review may also exhibit the dromedary camel breeding period, which is still unresolved, and thus may prove helpful in determining the exact time of mating, which is important for the success of assisted reproductive outcomes. Further, the review may contribute to a better understanding of the epididymal physiology in camel and may also prove useful in improving reproductive efficiency and population of this animal.

106 Exogenous melatonin administration improves behavioural signs, serum melatonin, testosterone, and semen quality in male dromedary (Camelus dromedarius) camels

The present study aimed to evaluate the effects of exogenous administration of melatonin to male camels on reproductive behaviour, seminal parameters, and serum concentrations of melatonin and testosterone during the non-breeding and subsequent breeding seasons. In September 2018, male camels (n=12) were randomly allocated to subcutaneous injections of either melatonin (MLT, 0.643 mg/kg; n=6) dissolved in corn oil, or plain corn oil; (control n=6). The camels were observed for behavioural signs of rut. A second dose of either MLT (1 mg/kg) or corn oil (control) was administered on 7 October 2018 subcutaneously, as camels did not show any change in behaviour until 6 October 2018, and the camels were again observed for behavioural signs of rut. Blood was collected from all camels on 1 September 2018, and then at weekly intervals until 7 January 2019. The serum was separated and stored until further assay of serum melatonin and testosterone using ELISA kits. Semen was collected from camels showing signs of rut period, and the reaction time, copulation time, and seminal parameters were evaluated. Data obtained was analysed by using the computer program SPSS (version 25; IBM Corp.), and means and standard errors were compared. Male reproductive behaviours (protrusion of soft palate, poll gland secretions, frequent urination, increased frothy salivation) were more pronounced in MLT-treated camels (83.33%) than in control camels (50%). Reaction time and copulation times were lower (112.81±30.06s and 229.8±37.91s) in MLT-treated camels than in controls (359.00±41.35s and 301.89±93.90s). Higher semen volume was observed in MLT-treated (5.34±2.06mL) than in control (3.11±1.75mL) camels (P&amp;lt;0.01). Semen collected from MLT-treated camels had more gel formation (81.25%), significantly higher sperm motility (67.50±2.32%), and increased sperm concentration (326.56±38.67 million mL−1) compared with samples obtained from the control males (P&amp;lt;0.01). Serum melatonin concentrations increased in both treated and control camels during the breeding season compared with concentrations before the breeding season. In MLT-treated camels, serum melatonin concentrations increased significantly and continued to be significantly higher than that in control camels for the entire study period (P&amp;lt;0.01). Serum testosterone concentrations were higher in both MLT-treated and control camels during the breeding season compared with those during the non-breeding season (P&amp;lt;0.01). We concluded that exogenous subcutaneous MLT administration improves sexual behaviour, seminal parameters, and serum testosterone concentrations during both the non-breeding and breeding seasons.

Effects of Stocking Density on Some Behavioral and Some Blood Biochemical Parameters in Camel during the Rut Period

This study investigated the effect of different stocking density on behavior, body condition score and some blood parameters of male camels in the rut period. Thirty-six male dromedary camels in rut period weighing from 350 to 400 kg were randomly divided in to three stock densities, 3 [lower stocking density (75%) (LSD)], 4 [normal stocking density (100%)(NSD)], and 5 [higher stocking density (125%)(HSD)] camels on 60 m2 of pen, respectively. Behavioral observations were performed for 10 weeks once per week for posture, maintenance, aggressive and social behavior using instantaneous scan sampling. Blood samples were collected at the end of the experiment for some serum blood parameters (Total protein, Albumin, Globulin, and Albumin/Globulin ratio) and blood hormones (Cortisol, Testosterone, T3, T4, and T3/T4 ratio). The results indicated that, in comparison with LSD and NSD, HSD increased the aggressive behavior, standing duration and cortisol level (P 0.05). Conclusively, HSD in group rearing had a bad effect on aggression, body condition score and sexual performance of male camels in the rut period.

221 Effect of age and rut period on the semen quality in reindeer (Rangifer tarandus)

Abstract Reindeer herding is a traditional activity of the indigenous peoples of the Arctic. Assisted reproductive technology in reindeer herding are under development. This is due to the difficulty of collecting reindeer sperm (Rangifer tarandus) in the Arctic. The aim of the work was to study the influence of age and rut period on the quality of reindeer (Rangifer tarandus) sperm. Semen was collected in Taimyr in autumn 2017, 2018. Ejaculate volume, total (TM) and progressive motility (PM) and sperm concentration were evaluated. TM, PM and sperm concentration were measured by CASA (computer-assisted semen analysis). Sperm was not found in caudae epididymidae in males at the age of six months. The sperm was collected only from caudae epididymidae from males aged 1.5 and 2.5 years. Collecting of ejaculated semen is possible in males from 3.5 years of age. The volume of ejaculate increased from 0.3±0.09 ml (mean±SD) at the age of 3.5 years to 0.7±0.09 ml at the age of 5.5 years and older (P &amp;lt; 0.05). Concentration of cells increased by 2 times in older males. It is known that reindeer sperm can be collected only during the rut. At the beginning and end of the rut, the collection of sperm by electroejaculation was not always successful, sperm was collected in 3 of 10 cases, while in the middle of the rut in 9 of 10 cases. There was no significant effect of the rut period on the ejaculate volume and sperm concentration. The lowest TM (51.1±2.16%) and PM (33.5±7.90%) were at the beginning of the rut, the highest at the end (73.0±5.02% and 59.0 ± 6,30%) (P &amp;lt; 0.01). Thus, the effect of age and rutting period on the reindeer sperm was observed. Authors acknowledge financial support from Russian Science Foundation, Grant No:17-16-01023.

107 Insights from roe deer oocyte transcriptome across embryonic diapause

Embryonic developmental arrest, known as diapause, has been reported in more than 130 species. However, its mechanisms are still not completely understood. In the roe deer, the only known ungulate that exhibits this phenomenon, diapause lasts for approximately 5 months, starting after the rut period in mid-July to early August and ending with embryo elongation and implantation in December/January. Little is known regarding oocyte characteristics during this period. Here, we analysed the roe deer oocyte transcriptome as a model to understand diapause effects on oocyte features during embryonic developmental arrest and reactivation. During regular hunting, immature oocytes were obtained by ovary slicing from diapause and nondiapause stages, and classified according to morphological characteristics. Only oocytes with &amp;gt;2 layers of compact cumulus cells and cytoplasm from 30 hunted females were used for analyses. Immature oocytes were denuded and snap frozen. Additional oocytes were cultured in maturation medium for 20-24h. Matured oocytes with a present polar body were snap frozen. Two pools of 10 immature and mature oocytes for both diapause and nondiapause stages were included (at least 4 donors/pool). Oocyte pools were processed using the Smart-seq 2 single-cell protocol (Illumina Inc., San Diego, CA, USA) for full-length cDNA and library preparation. We performed RNA-seq on an Illumina sequencer. The obtained Fastq files were clipped and analysed with a locally installed version of the Galaxy platform. Sequences were mapped against the roe deer transcriptome (unpublished data) and annotated against human and bovine transcripts. Differentially expressed genes (DEG; false discovery rate &amp;lt;1%) were identified using EdgeR (https://bioconductor.org/packages/release/bioc/html/edgeR.html) in immature (IMM) and mature (M) oocytes from diapause (D) and nondiapause (ND) stages. Additionally, to evaluate the effects of maturation on oocyte transcript abundancy, DEG between IMM and M oocytes for D and ND were identified. Multidimensional scaling resulted in clustering according to oocyte types. Gene ontology terms for biological processes were assigned using ToppCluster tools. A total of 23066, 23022, 22438, and 22532 transcripts were detected for IMM D, M D, IMM ND and M ND oocytes, respectively. Using false discovery rate filtering, we found 333 and 288 DEG in immature and mature oocytes, respectively. Furthermore, maturation changed the oocyte expression profiles during D (2233 DEG) and ND periods (2589 DEG). Gene ontology classification revealed that most of the DEG in immature oocytes were involved in macromolecule catabolic process and oxidation-reduction process. For mature oocytes, DEG were mostly related to regulation of chromosome condensation and ER and Golgi vesicle-mediated transport. Additionally, the top 20 DEG from IMM D v. M D oocytes were related to mRNA splicing, mRNA metabolic process, and mRNA processing. These processes were not identified in the top 20 DEG from IMM ND v. M ND oocytes. These preliminary results suggest that oocyte transcriptome analysis could disclose new pathways implicated in oocyte competence and embryonic developmental arrest and activation stages.