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J. Santiago-Moreno recibió una beca del Ministerio de Ciencia, Innovación y Universidades para visita de investigadores seniors a centros extranjeros (PRX19/00149). El Consejo Sueco de Investigación FORMAS (2017-00946 y 2019-00288), Estocolmo, Suecia, proporcionó apoyo analítico., This work identified the presence of AQPs in frozen-thawed sperm of wild ruminants and assessed the influence of the interaction between photoperiod and thyroxine on AQP expression, and on testosterone secretion. Thyroxine and melatonin were administered to ibexes. In a second experiment, performed in mouflons, circulating thyroxine was reduced via treatment with propylthiouracil (PTU), and an artificial long day (LD) photoperiod established. In the ibexes, the melatonin treatment increased the blood plasma testosterone concentration, reduced the cryoresistance ratio (CR) for sperm viability and the presence of an intact acrosome, and increased the percentage of sperm with AQP7 in the acrosome and of AQP3 and AQP10 in the midpiece. In the mouflons, neither the PTU treatment, the LD, nor the combination of both affected the CR of any sperm variable. The percentage of sperm with AQP3 increased in the post-acrosome region but decreased in the tail in the LD+PTU group. The percentage of sperm with AQP10 in the principal piece and endpiece was lower in the PTU+LD group than in the control and LD groups. The influence of photoperiod/melatonin on AQP expression might be indirectly exerted through changes in the testosterone concentration, and thus ultimately affect sperm cryoresistance., Agencia Estatal de Investigación (AEI) (AGL2017-85753-R y PID2020-113288RB-I00/AEI/10.13039/501100011033), MCINN (AGL2017-85753-R y PID2020-113288RB-I00/AEI/10.13039/501100011033), FEDER/EU, Depto. de Medicina y Cirugía Animal, Fac. de Veterinaria, TRUE, pub

Beca predoctoral de Pequeño financiada por la AEI (PRE2018-085637), Context: In the epididymis, epithelial cells manage changes in the luminal environment for proper sperm maturation. Moreover, aquaglyceroporins, a subgroup of aquaporins (AQP), modulate the transport of water, glycerol and other small molecules in epithelial cells. Aims: We aim to characterise the lining epithelium, quantify its cell composition and immunolocalise the aquaglyceroporins AQP3, AQP7, AQP9 and AQP10 alongside the epididymal ductus of three wild ruminant species, and to determine if species-specific differences could be associated with cauda sperm cryoresistance variations. Methods: Epididymides from Iberian ibex (n =5), mouflon (n =5) and chamois (n =6) were obtained. Cauda spermatozoa were collected and sperm parameters were analysed before and after freezing. Histology and immunohistochemistry of AQP3, 7, 9, 10 and T-CD3 were performed in the caput, corpus and cauda epididymal regions. Key results: This work first describes the lining epithelium in Iberian ibex, mouflon and chamois epididymis along the three anatomical regions, consisting of principal, basal, apical, clear and halo cells. However, the percentage of each cell type differed in ibex compared to mouflon and chamois. The positive T-CD3 immunolabeling of all the halo cells confirmed their T-lymphocyte nature. Aquaglyceroporin expression patterns were similar among species, except for differences in AQP7 and AQP10 immunolocalisation in ibex. Species-specific differences in epididymal sperm cryoresistance were confirmed. Conclusions: The epididymal epithelium of the three wild ruminants differ in their relative number of cell types and AQP immunolocalisation, which ultimately appears to affect cauda epidydimal spermatozoa cryoresistance. Implications: Our study provides information on the relevance of the quantitative composition and AQP pattern expression in epididymal lining epithelium on sperm cryoresistance., Agencia Estatal de Investigación (AEI), Depto. de Medicina y Cirugía Animal, Fac. de Veterinaria, TRUE, pub

Sheep, which were domesticated in the Fertile Crescent about 10,000-12,000 years ago, have been a key resource for human populations ever since. We, however, know little about how they were domesticated, and what happened to them after their initial expansion from their domestication area into all corners of Eurasia and later Africa and the Americas. In this thesis I use state-of-the-art methods in population genetics and archaeogenetics to try to elucidate how sheep have evolved into the big diversity of modern breeds we see today and what demographic events shaped modern sheep genetic landscape in Europe. We were able to characterize the demographic history of three key locations in Europe for sheep: Iberia, the Baltic region and the Mediterranean islands. Our results confirm that the initial Neolithic expansion into Europe followed two independent routes, through the Danube-Rhine axis in Central Europe and sailing through the Mediterranean, and that mouflons from Corsica and Sardinia descend from this last early domestic sheep. We were also able to identify two independent expansions into Europe of Eastern ancestry, one related with archaic long wool, a phenotype retained by primitive European sheep breeds, and a later one associated with more modern woolly phenotypes. This last expansion, that occurred slightly before or during the Roman period in Iberia, didn’t reached the Baltic region, whose breeds are still to this day displaying primitive phenotypes. Lastly, we were able to describe the phylogeny of modern wild and feral mouflons from the Mediterranean and the Middle East. My thesis highlight the dynamic nature of the demographic history of sheep, and how responsive it has been to human demographic and cultural changes.

In conservation biology, the ecological role of large herbivores has recently gained the attention it de- serves, particularly with rising interest in trophic rewilding. This shift is important as the growing human population and resource demands intensify environmental pressures, underscoring the need to understand the impact of these herbivores on ecosystems. However, the rewilding of herbivores can have strong top- down impacts on natural vegetation if the conservation programs do not take the grazing pressure into account. This can lead to challenges related to the regeneration of natural vegetation, hindering the over- all goals of the rewilding program. Thus, it is crucial to characterize and evaluate the grazing pressures of these herbivores in conservation areas. To address this challenge, this thesis serves as the first step to a comprehensive, year-round study employing eDNA metabarcoding of fecal samples to investigate the dietary habits of fallow deer and mouflon on Æbelø, a small protected island in Denmark. Despite its protected status, the conservation area is under significant browsing pressure from the herbivores. The focus of this work is the investigation of differences between the species and the temporal variance of the diet from April to September to understand the pressure of the animals on the ecosystem. The study detected 75 unique plant genera in the diets of fallow deer and mouflon on Æbelø, with forbs comprising 50.7%, graminoids 26.7%, trees 16.0%, and scrubs 6.7%. Despite similar overall diets between the two herbivores, monthly variations could be detected. Notably, PERMANOVA tests revealed significant monthly variations in plant composition for both mouflon (27.4%) and fallow deer (14.4%). Beta diversity dispersion analyses revealed nuanced monthly variations in the mouflon’s diet, particularly in June, compared to April and August. Fallow deer exhibited significa

In conservation biology, the ecological role of large herbivores has recently gained the attention it de- serves, particularly with rising interest in trophic rewilding. This shift is important as the growing human population and resource demands intensify environmental pressures, underscoring the need to understand the impact of these herbivores on ecosystems. However, the rewilding of herbivores can have strong top- down impacts on natural vegetation if the conservation programs do not take the grazing pressure into account. This can lead to challenges related to the regeneration of natural vegetation, hindering the over- all goals of the rewilding program. Thus, it is crucial to characterize and evaluate the grazing pressures of these herbivores in conservation areas. To address this challenge, this thesis serves as the first step to a comprehensive, year-round study employing eDNA metabarcoding of fecal samples to investigate the dietary habits of fallow deer and mouflon on Æbelø, a small protected island in Denmark. Despite its protected status, the conservation area is under significant browsing pressure from the herbivores. The focus of this work is the investigation of differences between the species and the temporal variance of the diet from April to September to understand the pressure of the animals on the ecosystem. The study detected 75 unique plant genera in the diets of fallow deer and mouflon on Æbelø, with forbs comprising 50.7%, graminoids 26.7%, trees 16.0%, and scrubs 6.7%. Despite similar overall diets between the two herbivores, monthly variations could be detected. Notably, PERMANOVA tests revealed significant monthly variations in plant composition for both mouflon (27.4%) and fallow deer (14.4%). Beta diversity dispersion analyses revealed nuanced monthly variations in the mouflon’s diet, particularly in June, compared to April and August. Fallow deer exhibited significa

Sheep, which were domesticated in the Fertile Crescent about 10,000-12,000 years ago, have been a key resource for human populations ever since. We, however, know little about how they were domesticated, and what happened to them after their initial expansion from their domestication area into all corners of Eurasia and later Africa and the Americas. In this thesis I use state-of-the-art methods in population genetics and archaeogenetics to try to elucidate how sheep have evolved into the big diversity of modern breeds we see today and what demographic events shaped modern sheep genetic landscape in Europe. We were able to characterize the demographic history of three key locations in Europe for sheep: Iberia, the Baltic region and the Mediterranean islands. Our results confirm that the initial Neolithic expansion into Europe followed two independent routes, through the Danube-Rhine axis in Central Europe and sailing through the Mediterranean, and that mouflons from Corsica and Sardinia descend from this last early domestic sheep. We were also able to identify two independent expansions into Europe of Eastern ancestry, one related with archaic long wool, a phenotype retained by primitive European sheep breeds, and a later one associated with more modern woolly phenotypes. This last expansion, that occurred slightly before or during the Roman period in Iberia, didn’t reached the Baltic region, whose breeds are still to this day displaying primitive phenotypes. Lastly, we were able to describe the phylogeny of modern wild and feral mouflons from the Mediterranean and the Middle East. My thesis highlight the dynamic nature of the demographic history of sheep, and how responsive it has been to human demographic and cultural changes.

Sheep, which were domesticated in the Fertile Crescent about 10,000-12,000 years ago, have been a key resource for human populations ever since. We, however, know little about how they were domesticated, and what happened to them after their initial expansion from their domestication area into all corners of Eurasia and later Africa and the Americas. In this thesis I use state-of-the-art methods in population genetics and archaeogenetics to try to elucidate how sheep have evolved into the big diversity of modern breeds we see today and what demographic events shaped modern sheep genetic landscape in Europe. We were able to characterize the demographic history of three key locations in Europe for sheep: Iberia, the Baltic region and the Mediterranean islands. Our results confirm that the initial Neolithic expansion into Europe followed two independent routes, through the Danube-Rhine axis in Central Europe and sailing through the Mediterranean, and that mouflons from Corsica and Sardinia descend from this last early domestic sheep. We were also able to identify two independent expansions into Europe of Eastern ancestry, one related with archaic long wool, a phenotype retained by primitive European sheep breeds, and a later one associated with more modern woolly phenotypes. This last expansion, that occurred slightly before or during the Roman period in Iberia, didn’t reached the Baltic region, whose breeds are still to this day displaying primitive phenotypes. Lastly, we were able to describe the phylogeny of modern wild and feral mouflons from the Mediterranean and the Middle East. My thesis highlight the dynamic nature of the demographic history of sheep, and how responsive it has been to human demographic and cultural changes.

This work examines the effect of equilibration time with extender on ultra-rapidly frozen-thawed wild ruminant epididymal (origin: Iberian ibex) and ejaculated (origin: mouflon) sperm variables. Sperm samples were prepared either without prior equilibration, or equilibrated for 30 min before freezing. Higher quality (p < 0.05) frozen-thawed spermatozoa were obtained when equilibration was allowed, for ejaculated sperm in terms of sperm motility, acrosome apical ridge integrity, sperm viability, and percentage of normal cells, and for epididymal sperm in terms of linearity and straightness of sperm movement. The sperm head area, head perimeter, head length and head width were smaller (p < 0.01) in the equilibrated than non-equilibrated frozen-thawed epididymal sperm; no such dimensional changes were recorded for ejaculated sperm. In conclusion, equilibration prior to ultra-rapid freezing improves the cryoresistance of sperm cells, although viable sperm cells can be obtained without equilibration. The epididymal sperm showed greater cryoresistance, supporting the idea that it is more resistant to freeze-thawing than ejaculated sperm.

In the epididymis, epithelial cells manage changes in the luminal environment for proper sperm maturation. Moreover, aquaglyceroporins, a subgroup of aquaporins (AQP), modulate the transport of water, glycerol and other small molecules in epithelial cells.

A female mouflon, weighing 40 kilograms, was submitted to the diagnostic laboratory of the Institute of Veterinary Medicine of Serbia for determining the potential cause of death. Necropsy revealed massive hemorrhages in subcutaneous andintermuscular tissue and on papillary muscle. Petechiae and ecchymoses were found on the omen-tum, mesentery and adipose tissue of heart, kidneyand costal pleura.Haemorrhagic-necrotic enteritis in duodenum and jejunum was characterized by catarrhal hemorrhagic inflammation withthe presence of mucous and bloody content, whereas gas bubbles in the submucosa have also been confirmed. Bacterial cultures from sampled organs were iden-tified as Clostridium perfringens type A, Clostridium septicum, and Clostridium sordelli.Based on the established pathological and histological changes and the results of the bacteriological, biochemical, and molecular examination, the state of septic shock and toxemia with disseminated massive bleeding was the immediate cause of mouflon death. The septic condition is a consequence of enterotoxemia caused by Clostridium perfringens type A, Clostridium septi-cum,and Clostridium sordelliinfection.

A female mouflon, weighing 40 kilograms, was submitted to the diagnostic laboratory of the Institute of Veterinary Medicine of Serbia for determining the potential cause of death. Necropsy revealed massive hemorrhages in subcutaneous andintermuscular tissue and on papillary muscle. Petechiae and ecchymoses were found on the omentum, mesentery and adipose tissue of heart, kidneyand costal pleura.Haemorrhagic-necrotic enteritis in duodenum and jejunum was characterized by catarrhal hemorrhagic inflammation withthe presence of mucous and bloody content, whereas gas bubbles in the submucosa have also been confirmed. Bacterial cultures from sampled organs were identified as Clostridium perfringens type A, Clostridium septicum, and Clostridium sordelli.Based on the established pathological and histological changes and the results of the bacteriological, biochemical, and molecular examination, the state of septic shock and toxemia with disseminated massive bleeding was the immediate cause of mouflon death. The septic condition is a consequence of enterotoxemia caused by Clostridium perfringens type A, Clostridium septicum, and Clostridium sordelliinfection.

This work identified the presence of AQPs in frozen-thawed sperm of wild ruminants and assessed the influence of the interaction between photoperiod and thyroxine on AQP expression, and on testosterone secretion. Thyroxine and melatonin were administered to ibexes. In a second experiment, performed in mouflons, circulating thyroxine was reduced via treatment with propylth iouracil (PTU), and an artificial long day (LD) photoperiod established. In the ibexes, the melatonin treatment increased the blood plasma testosterone concentration, reduced the cryoresistance ratio (CR) for sperm viability and the presence of an intact acrosome, and increased the percentage of sperm with AQP7 in the acrosome and of AQP3 and AQP10 in the midpiece. In the mouflons, neither the PTU treatment, the LD, nor the combination of both affected the CR of any sperm variable. The percentage of sperm with AQP3 increased in the post-acrosome region but decreased in the tail in the LD+PTU group. The percentage of sperm with AQP10 in the principal piece and endpiece was lower in the PTU+LD group than in the control and LD groups. The influence of photoperiod/melatonin on AQP expression might be indirectly exerted through changes in the testosterone concentration, and thus ultimately affect sperm cryoresistance.

The use of multidisciplinary approaches of investigation including biological, biogeographical, historical, morphological, and genetic analysis, can be useful in identifying and preserving biodiversity. The present study focuses on the characterisation and conservation of a mouflon population (Ovis gmelini musimon) from the Mediterranean island of Giglio. Here we provide the first molecular data on the Giglio population and compare it with mouflons from Sardinia, Elba, and Corsica using both nuclear and mitochondrial markers. Our results suggest that the Giglio mouflon harbours genetic variability likely of Sardinian origin but not represented in the current Sardinian mouflon diversity. Although not presenting the typical characteristics of an invasive alien species, the Giglio mouflon is being subjected to eradication through culling or trapping and surgical sterilization. The molecular evidence we report highlights that such actions are causing the irremediable loss of ancestral genetic variants of the genus Ovis. Finally, we highlight how a multidisciplinary approach is necessary to aid the conservation and management of the anthropochorous populations of Mediterranean mammals.

Population genetic studies provide accurate information on population structure, connectivity, and hybridization. These are key elements to identify units for conservation and define wildlife management strategies aimed to maintain and restore biodiversity. The Mediterranean island of Sardinia hosts one of the last autochthonous mouflon populations, descending from the wild Neolithic ancestor. The first mouflon arrived in Sardinia ~ 7000 years ago and thrived across the island until the twentieth century, when anthropogenic factors led to population fragmentation. We analysed the three main allopatric Sardinian mouflon sub-populations, namely: the native sub-populations of Montes Forest and Mount Tonneri, and the reintroduced sub-population of Mount Lerno. We investigated the spatial genetic structure of the Sardinian mouflon based on the parallel analysis of 14 highly polymorphic microsatellite loci and mitochondrial D-loop sequences. The Montes Forest sub-population was found to harbour the ancestral haplotype in the phylogeny of European mouflon. We detected high levels of relatedness in all the sub-populations and a mitochondrial signature of hybridization between the Mount Lerno sub-population and domestic sheep. Our findings provide useful insights to protect such an invaluable genetic heritage from the risk of genetic depletion by promoting controlled inter-population exchange and drawing informed repopulation plans sourcing from genetically pure mouflon stocks.

Hybridisation of wild populations with their domestic counterparts can lead to the loss of wildtype genetic integrity, outbreeding depression, and loss of adaptive features. The Mediterranean island of Sardinia hosts one of the last extant autochthonous European mouflon (Ovis aries musimon) populations. Although conservation policies, including reintroduction plans, have been enforced to preserve Sardinian mouflon, crossbreeding with domestic sheep has been documented. We identified panels of single nucleotide polymorphisms (SNPs) that could act as ancestry informative markers able to assess admixture in feral x domestic sheep hybrids. The medium-density SNP array genotyping data of Sardinian mouflon and domestic sheep (O. aries aries) showing pure ancestry were used as references. We applied a two-step selection algorithm to this data consisting of preselection via Principal Component Analysis followed by a supervised machine learning classification method based on random forest to develop SNP panels of various sizes. We generated ancestry informative marker (AIM) panels and tested their ability to assess admixture in mouflon x domestic sheep hybrids both in simulated and real populations of known ancestry proportions. All the AIM panels recorded high correlations with the ancestry proportion computed using the full medium-density SNP array. The AIM panels proposed here may be used by conservation practitioners as diagnostic tools to exclude hybrids from reintroduction plans and improve conservation strategies for mouflon populations.

Camera trapping allows scientists to study activity patterns of animals under natural conditions. However, comparisons of activity patterns across seasons or latitudes can be biased, because activity is often attuned to sunrise and sunset, the timing of which varies with latitude and season. Existing transformation methods to solve this problem have limitations. Here, we explore whether and how activity patterns can be transformed more accurately using two alternative ?double anchoring? transformations ? equinoctial and average anchoring ? that anchor activity time to two chosen anchor points during the study period. Using simulated noisy datasets mimicking species with either crepuscular, diurnal or cathemeral activity patterns, we compared the ability of different transformation methods to extract the latent pattern and activity levels under different study conditions. We found that average anchoring best retrieved the original diel activity pattern and yielded accurate estimates of activity level. Two alternative transformation methods ? single anchoring and equinoctial anchoring ? performed less well. Bias in estimates from using untransformed clock times was most marked (up to 2.5-fold overestimation) for longer studies covering 4?5 months either side of an equinox at high latitude, and focusing on crepuscular species. We applied the average anchoring method to 9 months of data on Red deer Cervus elaphus, Wild boar Sus scrofa and Mouflon Ovis amon musimon activity as captured by camera traps in National Park Hoge Veluwe, the Netherlands. Average anchoring revealed more pronounced peaks of activity after sunset than was apparent from untransformed data in red deer and wild boar, but not for mouflon, a cathemeral species. Similarly, activity level was lower when calculated using average anchored time for red deer and wild boar, but no difference was observed for mouflon. We conclude that transformation of time might not be necessary at latitudes below 20

Camera trapping allows scientists to study activity patterns of animals under natural conditions. However, comparisons of activity patterns across seasons or latitudes can be biased, because activity is often attuned to sunrise and sunset, the timing of which varies with latitude and season. Existing transformation methods to solve this problem have limitations. Here, we explore whether and how activity patterns can be transformed more accurately using two alternative ‘double anchoring’ transformations – equinoctial and average anchoring – that anchor activity time to two chosen anchor points during the study period. Using simulated noisy datasets mimicking species with either crepuscular, diurnal or cathemeral activity patterns, we compared the ability of different transformation methods to extract the latent pattern and activity levels under different study conditions. We found that average anchoring best retrieved the original diel activity pattern and yielded accurate estimates of activity level. Two alternative transformation methods – single anchoring and equinoctial anchoring – performed less well. Bias in estimates from using untransformed clock times was most marked (up to 2.5-fold overestimation) for longer studies covering 4–5 months either side of an equinox at high latitude, and focusing on crepuscular species. We applied the average anchoring method to 9 months of data on Red deer Cervus elaphus, Wild boar Sus scrofa and Mouflon Ovis amon musimon activity as captured by camera traps in National Park Hoge Veluwe, the Netherlands. Average anchoring revealed more pronounced peaks of activity after sunset than was apparent from untransformed data in red deer and wild boar, but not for mouflon, a cathemeral species. Similarly, activity level was lower when calculated using average anchored time for red deer and wild boar, but no difference was observed for mouflon. We conclude that transformation of time might not be necessary at latitudes below 20°, or in

L’exploitation durable de la faune sauvage doit minimiser les impacts de la récolte sur l’écologie et l’évolution des espèces exploitées et éviter d’affecter les populations dans les aires protégées. La récolte sélective, surtout si elle est importante, peut induire des conséquences évolutives. Les refuges, aires protégées où aucune chasse n’est permise, peuvent agir comme source d’individus reproducteurs non sujets à cette sélection artificielle et tamponner les effets de la récolte sélective si des individus originaires des aires protégées vont se reproduire dans les zones chassées. Cependant, le rôle des refuges sur la rescousse phénotypique des espèces chassées pour le trophée a rarement été évalué empiriquement. Ce projet de maîtrise visait à évaluer les variations spatiales et temporelles dans les effets de la proximité des refuges sur la taille des cornes, un trait lié au succès reproducteur des mâles, et l’âge à la récolte dans les populations de mouflon d’Amérique (Ovis canadensis) chassées. Pour ce faire, j’ai utilisé une base de données à long terme d’environ 6 000 béliers récoltés sur 39 ans (1975-2013) en Alberta. Les résultats montrent que la longueur des cornes, un trait ciblé par les chasseurs, et l’âge à la récolte augmentaient avec la proportion de refuges à l’intérieur d’une zone tampon de 25 km de rayon autour de chaque localisation de bélier tué. Toutefois, la circonférence à la base des cornes n’était pas influencée par la proximité aux refuges. Le nombre de béliers récoltés augmentait significativement durant les 10 derniers jours de la saison de chasse en octobre, correspondant avec le début de la migration pour le rut. Ceux abattus pendant les 10 derniers jours de la saison étaient en moyenne 17% plus près de la frontière d’un refuge que ceux récoltés plus tôt pendant la saison de chasse. Nos résultats supportent l’hypothèse selon laquelle des mâles commencent à migrer des aires protégées à la fin de la saison de chasse, soit avant le rut, v

Comprendre de quelle façon les populations animales répondent aux conditions qui prévalent dans leur environnement revêt une grande importance. Les conditions climatiques et météorologiques sont une source importante de variabilité dans l'environnement et celles-ci ont des répercussions sur les espèces sauvages, en affectant leur physiologie, leur comportement et leurs ressources. Les ongulés alpins et nordiques font face à une succession annuelle de conditions environnementales favorables et défavorables, entraînant chez ceux-ci d'importants changements de masse saisonniers. Chez ces grands herbivores, la masse est importante puisqu'elle est positivement corrélée à la survie et à la reproduction. C'est pourquoi il est essentiel d'investiguer les paramètres affectant les changements de masse saisonniers. L'objectif principal de ma maîtrise était donc d'identifier et de mieux comprendre l'effet des conditions climatiques et météorologiques sur les changements de masse estivaux et hivernaux d'un ongulé alpin: le mouflon d'Amérique (Ovis canadensis). Pour atteindre cet objectif, j'ai utilisé les données du suivi à long terme de la population de mouflons de Ram Mountain, Alberta. Les mesures de masse répétées prises lors des captures permettent d'estimer la masse printanière et automnale des individus, ainsi que leur gain de masse estival et leur changement de masse hivernal. En affectant les coûts énergétiques de la thermorégulation et des déplacements et en influençant la végétation, les conditions climatiques et météorologiques peuvent avoir d'importantes conséquences sur les changements de masse des ongulés alpins. La température, les précipitations et un indice de climat global (le «Pacific Decadal Oscillation»; PDO) ont donc été utilisés afin de caractériser les conditions environnementales et d'investiguer les effets de ces variables sur les changements de masse saisonniers des individus de différentes classes d'âge et de sexe. Des températures froides au printem

Studies on seasonal horn development and the endocrine mechanism regulating its pattern in wild ruminants are scarce. The aim of this paper was to study the influence of photoperiod and prolactin (PRL) on horn growth in two wild ruminant species the European mouflon and the Iberian ibex. Eighteen male ibexes and 13 mouflon rams, maintained in captivity, were divided into three groups a control group, kept under a natural photoperiod (latitude, 40°25′ N); a long-day group, exposed to an artificial photoperiod of 15-h light and 9-h darkness; and a group treated with bromocriptine (BCR; 10 mg twice weekly during spring and summer) to induce hypoprolactinaemia. Horn length growth (HLG) was recorded weekly for 18 months; plasma PRL concentrations were measured twice monthly by radioimmunoassay. In the ibexes of the long-day group, the period of strong horn development during spring-summer was significantly reduced by 2 months compared with the controls. In the mouflons of the long-day group, this same period was significantly increased by 9 months. In the BCR-treated animals, hypoprolactinaemia was observed in both species, but HLG was the same as in the corresponding controls. The present results suggest that the seasonal pattern of horn growth of wild ruminants is primarily modulated by photoperiod in a species-dependent manner. The persistence of resurgence of horn growth during spring in the BCR-induced hypoprolactinaemic animals of both species suggests that annual variations in blood PRL concentration have no effect on seasonal variation in horn growth. © 2012 Springer-Verlag.

The aim of the present study was to estimate the genetic intra-breed variability of Churra tensina and Churra lebrijana endangered breeds and to establish genetic relationships with Churra, Latxa and Merino breeds, as well as Spanish mouflon, by using 28 microsatellite markers, to provide useful information for their conservation. Allele frequencies and heterozygosity revealed high genetic variation in the two endangered breeds despite their small population size. Estimates of inbreeding coefficient (FIS) were significant for all breeds studied, except for Churra lebrijana breed. The highest inbreeding coefficient (FIS=0.143) was found in the Spanish mouflon. Genetic differentiation tests (FST=0.121) and assignment of individuals to populations indicated the existence of defined breed populations, and low genetic flow between these breeds. The highest pairwise Reynolds distance (DR) values were observed between Mouflon and the domestic sheep breeds. Considering only domestic sheep breeds, the Churra lebrijana breed showed the highest pairwise DR values. The lowest values were found between Latxa and the other domestic sheep, except for Churra lebrijana. Results of pairwise DR values, as well as phylogenetic tree and bottleneck analysis showed an important genetic isolation of the Churra lebrijana breed from the other Churra types, and genetic signatures of a demographic bottleneck. Finally, structure analysis of populations detected a population subdivision in the Latxa sheep breed. In conclusion, this study presents valuable insight into the existing genetic variability of two Spanish endangered breeds, as well as the first study in Spanish mouflon based on microsatellite analysis. The high degree of variability demonstrated in Churra tensina and Churra lebrijana implies that these populations are rich reservoirs of genetic diversity. © 2010 Elsevier B.V.

This study examines the patterns of melatonin secretion during postnatal development in wild (mouflon; n = 7) and domestic (Spanish Merino; n = 6) female lambs under their natural photoperiod conditions. The aim was to determine whether these types of sheep which differ in the timing of puberty, also differ in the establishment of daily melatonin secretory rhythms and/or in the nocturnal plasma melatonin secretion. In addition, the time when the lambs first reached nocturnal levels of melatonin similar to adults was also evaluated. For this purpose, the melatonin secretion in lambs was compared with those of their mothers. A day/night (D/N) difference in plasma melatonin concentration was noticed as early as 1 day after birth in the Merino female lambs (D 5.9 ± 1.0 pg/ml compared to N 22.0 ± 3.3 pg/ml; p < 0.05), and by 1 week after birth in the mouflon female lambs (D 4.9 ± 0.3 pg/ml compared to N 56.9 ± 15.3 pg/ml; p < 0.05). An effect of the genotype (p < 0.05) and age (p < 0.01) was detected on mean nocturnal plasma melatonin concentrations, which were lower in the Merino than in the mouflon lambs. Night-time plasma concentration of melatonin was also high in mouflon than in Merino mothers (p < 0.05). No differences were detected between the wild genotype and the domestic one in the time when the lambs first reached nocturnal levels of melatonin similar to those of their mothers. © 2009 Elsevier B.V. All rights reserved.

Serial transrectal ultrasonographies were performed measuring different structures of mouflon (Ovis gmelini musimon) fetuses to establish their gestational age. Data were obtained from 14 mouflon ewes that became pregnant after estrous synchronization. From day 25 of gestation onward, the crown-rump length and the trunk diameter of the embryo were estimated. Later, when the fetal organs and structures could be distinguished, several measurements were done in the skull (occipito-snout length and biparietal and orbit diameters), the trunk (thoracic diameter and width of vertebrae), and the abdominal cavity (stomach and kidney longitudinal diameters); femur length was also determined. All fetal measurements were correlated with gestational age (P < 0.001), but the parameters showing the highest correlation with time (R2 up to 0.94) were the crown-rump and occipito-snout lengths and the thoracic and biparietal diameters. No significant differences were observed in pregnancies with one or two fetuses in the period studied. Copyright 2005 by American Association of Zoo Veterinarians.

Annual variations in the growth of horns, and their correlation with seasonal changes of testicular size, and prolactin (PRL) and melatonin secretion were monitored in six pubertal mouflon rams living in their original latitude (40°N). Mouflons born and maintained under captive conditions were classified in two age classes sub-adult (2 years; n = 3) and adult (≥3 years; n = 3). The rate of horn growth was greater (P < 0.001) in sub-adult than in adult mouflon rams. Horn growth was influenced by season in both adult and sub-adult mouflons (P < 0.05) with largest monthly growth occurring in spring and summer. Seasonal variations of plasma PRL concentrations were correlated with horn growth in adult, but not in sub-adult mouflon rams. The rate of horn growth was inversely correlated with testicular size (r = -0.5, P = 0.07). Seasonal changes in the amplitude of the daily melatonin rhythm in solstices and equinoxes were observed, which were not correlated with variations in the rate of horn growth. These results provide support for a possible role of PRL in the control of growth of horns in the adult mouflon. © 2004 Elsevier B.V. All rights reserved.

Van oudsher zijn moeflons opgenomen in de jachtwetten van Nederland en België. Als niet inheemse dieren die alleen binnen rasters worden gehouden, zijn ze niet opgenomen in de Flora- en faunawet van 2000. Moeflons worden aan de ene kant beschouwd als wild; aan de andere kant staan ze vermeld in een boek over schapenrassen in Nederland, zij het met de aantekening dat er weinig fokkers zijn en dat er geen stamboom wordt bijgehouden

The aims of this study were to examine whether mouflons exposed to constant long and short day photoperiods are able to exhibit an annual cycle of hair growth and moult, and prolactin (PRL) secretion. Mouflon ewes were assigned to three groups of treatment. Ewes were maintained, either under natural photoperiod (control, n=9), or received a series of subcutaneous melatonin implants from December to April (n=8), or were exposed to a constant long day photoperiod (16-hlight8-hdark; 16L8D) during 18 months (n=7). Blood was collected weekly to determine PRL concentrations, and hair samples were clipped weekly from the base of the neck to measure the length of predominant hair. Under constant long days and with melatonin implants, mouflons expressed an annual rhythm of PRL secretion, even though these treatments modified the times of rise or falling of PRL concentrations throughout the year. Hair growth initiation was almost coincident with the summer solstice in both control and melatonin-implanted mouflons but occurred two months earlier in long day hold mouflons (P<0.001). Long day hold mouflons had a lower hair growth rate than control and melatonin-implanted mouflons (P<0.001), and at the end of the experiment, a shorter hair length (3.4±0.24cm; P<0.01) than control (4.3±0.17cm), and melatonin-implanted mouflons (4.2±0.12cm). Our data support the conclusion that in mouflon, an endogenous circannual rhythm of PRL secretion exists, and that the seasonal cycle of hair growth and moult appears to depend, at least in part, on circulating levels of PRL. © 2004 Elsevier Inc. All rights reserved.

Daily transrectal ultrasonographies were conducted to study development of all follicles with antral diameters ≥2 mm during the follicular phase of oestrous cycle in Mouflon, a strictly monovular wild-sheep. A total of 14 follicular phases was studied after oestrus synchronization with two cloprostenol doses, 9 days apart, in five cyclic Mouflon ewes. In 13 cycles (92.8%), the ovulatory follicle arose from those antral follicles present in both ovaries when luteolysis was induced, being the largest one with a mean size of 4.4±0.3 mm at that moment in 10 cycles (76.9%). The remaining cycles had a larger follicle, but it was decreasing in size. Appearance of new follicles ≥2 mm in size remained unaffected during the follicular phase (3.7±0.2), but there was found a linear decrease in the number of those growing to ≥3 mm (2.5±0.4 to 1.1±0.2, P < 0.05) and ≥4 mm (0.6 ±0.2 to 0.1±0.1, P < 0.005), detection of new follicles growing to ≥5 mm was negligible. Then, number of medium (4-5 mm) growing follicles present in both ovaries decreased from 1.5 ± 0.3 at 0 h to 0.3 ± 0.1 at 72 h (P < 0.005). In conclusion, the single ovulatory follicle is the largest growing follicle present in both ovaries at the moment of luteolysis. This follicle is selected to grow and ovulate while development of other follicles is inhibited. © 2001 Elsevier Science B.V.

The timing of the onset of puberty, duration of seasonal ovulatory activity, and length of postpartum anestrus were studied by means of blood plasma progesterone concentrations in a flock of European female mouflons (Ovis gmelini musimon) maintained in captivity under natural photoperiod (40°25′N). Concentrations of progesterone in the peripheral blood were determined by radioimmunoassay in samples collected from the jugular vein twice a week. First ovulations in the breeding season were highly synchronized and occurred in mid-October. In contrast, the cessation of ovulatory cycles showed significant variation among females and extended from February to May, depending on age, with 2-yr-old animals exhibiting the longest anovulatory period (P < 0.01). When lambing occurred within the breeding season (February-April), 12 out of 26 animals had their first ovulation 25 ± 1.8 days after parturition. The 14 late-lambing females had the first postpartum ovulation delayed until the next breeding season. March/April-born mouflon lambs that reached a minimum threshold body weight (23.8 ± 0.6 kg) in their first breeding season reached puberty at 8 mo of age. In those with slower growth rates, however, the prepubertal period was extended throughout the first breeding and nonbreeding seasons, reaching puberty during the breeding season of the following year at 19 mo of age and 27 ± 0.3 kg body weight. Further, attainment of puberty in ewe lambs born in June/July was also delayed until the breeding season of the following year, when animals had reached a threshold body weight at 17 mo of age.

Embryos from five anesthetized mouflons (Ovis gmelini musimon), superovulated with FSH-o (Ovagen™) were transferred into preselected Spanish Merino sheep (Ovis aries). Myorelaxation was complete in four of five donor mouflons. The status of the uterus of potential recipients was evaluated by transrectal ultrasonography, and those ewes with fluid in the uterine horn were rejected. The corpus luteum in each ewe was assessed ultrasonographically the day before surgery. Plasma progesterone levels and the quality of the corpora lutea were the criteria for selection of recipients. Ten embryos were transferred to the five selected Spanish Merino recipients, resulting in four pregnancies and seven live-born lambs, including three sets of twins. This study shows that determination of plasma progesterone levels combined with ultrasonographic assessment of the corpus luteum provides information useful for screening of potential recipients.

Seasonal changes in nocturnal prolactin secretion and their relationship with melatonin secretion were monitored in wild (Mouflon, Ovis gmelini musimon) and domesticated sheep (breed Manchega, Ovis aries). Two groups of eleven adult females each, were maintained outdoors under natural photoperiod. Plasma concentrations of prolactin and melatonin were determined during the summer and winter solstices and the autumn and spring equinoxes. Blood samples were collected every 3 h during the night hours, and 1 h before and after the onset of darkness and sunrise. Maximum mean plasma concentrations of prolactin during the dark-phase in Mouflons were observed in the summer solstice, (P < 0.001) and in the summer solstice and spring equinox in Manchega ewes (P < 0.001). Mean plasma concentrations of prolactin were higher in the wild species (P < 0.001) during the summer solstice. In contrast, during the spring equinox, mean levels of prolactin were higher in Manchega ewes than in Mouflons (P < 0.05). Plasma prolactin concentrations showed a nocturnal rhythm in both breeds, with seasonal variations (P < 0.001). The increase in plasma melatonin levels during the first hour after sunset was accompanied to increasing concentrations of PRL 1 h after the onset of darkness, only in the autumn and spring equinox for the Mouflon, and in the summer solstice and spring equinox for the Manchega ewes. In Mouflons, the fall of plasma PRL concentrations about the middle dark-phase in all the periods studied, coincided with high levels of melatonin. A similar relation was observed in Manchega ewes only in the winter solstice and spring equinox. The current study shows that the nocturnal rhythm of prolactin secretion exhibits seasonal variation; differences in the patterns of prolactin secretion between Mouflon and Manchega sheep are taken to represent the effects of genotype. © 2000 Elsevier Science B.V.

Seasonal changes in ovulatory activity, plasma prolactin and melatonin concentrations were monitored in a wild (Mouflon) and a domesticated (Manchega) breed of sheep, both originating and living under similar latitudes (40°N). Mouflons express ovarian cycles significantly later than Manchega ewes (October vs. July, P < 0.001); however, they ended cycling one month later than Manchegas (April vs. March, P < 0.05). While prolactin concentrations were high when Manchega ewes started to cycle, they were at their lowest concentrations when Mouflons started cycling. Overall, mean prolactin concentrations were higher (P < 0.001) in Mouflons than Manchegas throughout most of the year. Within the limits of sampling frequency, the duration of melatonin secretion was similar in both groups during the solstice and equinox periods; however, the amplitude was lower (P < 0.01) in Mouflons than Manchegas during the solstice periods. The significant breed differences in the seasonal hormonal changes may be attributed to a genetic influence in the endocrine responses to the same photoperiodic cues.

The objective of this study was to compare ovulatory activity of Mouflon and Manchega ewes lambing at different times of the year. A total of 38 adult European Mouflon and 26 Manchega ewes were divided into two groups according to whether lambing occurred in late winter/early spring or summer. Plasma progesterone concentrations were monitored to assess the interval to first ovulation after parturition. Both season and type of sheep affected the postpartum interval. When parturition occurred towards the end of the breeding season for Mouflon (February-March), 12 of 26 animals had a mean (±s.e.) interval to first ovulation of 25 ± 1.8 days and exhibited between 1 and 6 short or normal cycles before the onset of anoestrus. The remaining 14 animals did not resume ovulatory activity until the following breeding season which started in October. Similarly, female Mouflon (n = 12) giving birth in June reinitiated their breeding activity only at the start of the following season in October. Manchega ewes that lambed in April (n = 11) and June (n = 15) had postpartum intervals to first ovulation of 111.5 ± 4.1 and 31.5 ± 1.9 days, respectively. Both groups of Manchegas reinitiated ovulatory activity at the start of the expected breeding season for the breed (July). It can be concluded that the time of year is a major factor controlling the duration of ovarian inactivity following parturition in both Mouflon and Manchega ewes. (C) 2000 Elsevier Science B.V.

Die Verdaulichkeit langsam abbaubarer Pflanzenbestandteile (Cellulose) steigt mit zunehmender Partikelverweilzeit im Vormagen von Wiederkäuern. Die Ingestaverweilzeit im Magen-Darm-Kanal ist abhängig von der Größe der Fermentationskammern, der Nahrungsaufnahme, vom Speichelfluß und von der selektiven Retention von Futterpartikeln. Die mittlere Retentionszeit (MRT) von Flüssigkeit und Partikeln müßte sich zwischen den Tierarten unterscheiden und saisonbedingt in Abhängigkeit von der Qualitüt und des Angebotes der Nahrung verändern. Mit der Messung der Ingestapassage an Rehen als Konzentratselektierer im Vergleich zu Mufflons als Grasfresser werden Faktoren der Anpassung an das jahreszeitlich wechselnde Nahrungsangebot dieser verschiedenen Wildtierarten untersucht. Voraussetzung für die Durchführung der Versuche war die Handaufzucht von sechs Rehkitzen und fünf Mufflonlämmern. Den Tieren wurde zum dorsalen Pansensack eine Vormagenkanüle implantiert. Die Haltung der Tiere erfolgte in Gehegen mit natürlicher Vegetation. Den Rehen und Mufflons wurden über die Vormagenfistel ein Marker für Flüssigkeit (Co-EDTA) und ein Marker für Partikel (Chrom-markiertes Heu) verabreicht. Anschließend wurde 5 Tage regelmäßig alle 3 bis 4 h Kot gesammelt. Die Co-/Cr-Konzentrationen der mit Schwefelsäure aufbereiteten Proben wurden atomabsorptionsspektrometrisch gemessen. Die Berechnung der Retentionszeiten der Flüssigkeit und Partikel im Gastro-Intestinal-Trakt (GIT) und im Ruminoretikulum (RR) erfolgte nach Thielemans et al. (1978), nach Grovum und Williams (1973) und Lechner-Doll (1990). Derartige Untersuchungen wurden erstmals unter annähernd natürlichen Bedingungen vergleichend an Rehen und Mufflons durchgeführt. Die Gesamtverweildauer von Flüssigkeit und Partikeln im Gastro-Intestinal-Trakt war beim Reh (MRTFlüss.GIT = 18,1 ± 2,4 h, MRTPart.GIT = 23,6 ± 3,8 h) im gesamten Jahresverlauf kürzer als beim Mufflon (MRTFlüss.GIT = 22,5 ± 3,9 h, MRTPart.GIT = 36,0 ± 4,2 h). Die Partikelver, The digestibility of slowly fermentable/digestible plant material (cellulose) increases with increasing particle retention time in the forestomach of ruminants. The retention time in the gastro-intestinal-tract depends on the size of the fermentation chambers, the food intake, the saliva flow and the selective retention of food particles. The mean retention time (MRT) of fluid and particles should differ between ruminant species and, according to differences in food quality and availability, between seasons. By measuring the ingesta passage rate of roe deer, a concentrate selector, in comparison with mouflon, a grass and roughage eater, adaptation factors of these different species to the seasonally changing forage supply were investigated. A prerequisite for the trials was the hand-rearing of six roe deer fawns and five mouflon lambs. Rumen fistulas were implanted in all adult animals leading to the dorsal ruminal chamber. The animals were kept in adequate enclosures with natural vegetation. A fluid (Co-EDTA) and a particle (Cr-mordanted fibre) marker were applied to roe deer and mouflons via the rumen fistula. After marker application, faecal samples were collected every 3 to 4 hours for 5 days. Faecal samples were prepared with sulphuric acid and the Co- and Cr-concentrations were measured by atomic absorption spectrophotometry. The retention time of fluid and particle phase in the gastro-intestinal-tract and in the ruminoreticulum were calculated according to Thielemans et al. (1978), Grovum und Williams (1973) und Lechner-Doll (1990). Such investigations were carried out for the first time under natural conditions comparing roe deer and mouflons. The total retention time of fluid and particles in the gastro-intestinal-tract was for roe deer (MRTfluid GIT = 18,1 ± 2,4 h, MRTpart.GIT = 23,6 ± 3,8 h) shorter than for mouflon (MRTfluid GIT = 22,5 ± 3,9 h, MRTpart.GIT = 36,0 ± 4,2 h ) during the whole year. The retention time of particles in the ruminoreticulum was

Die Verdaulichkeit langsam abbaubarer Pflanzenbestandteile (Cellulose) steigt mit zunehmender Partikelverweilzeit im Vormagen von Wiederkäuern. Die Ingestaverweilzeit im Magen-Darm-Kanal ist abhängig von der Größe der Fermentationskammern, der Nahrungsaufnahme, vom Speichelfluß und von der selektiven Retention von Futterpartikeln. Die mittlere Retentionszeit (MRT) von Flüssigkeit und Partikeln müßte sich zwischen den Tierarten unterscheiden und saisonbedingt in Abhängigkeit von der Qualitüt und des Angebotes der Nahrung verändern. Mit der Messung der Ingestapassage an Rehen als Konzentratselektierer im Vergleich zu Mufflons als Grasfresser werden Faktoren der Anpassung an das jahreszeitlich wechselnde Nahrungsangebot dieser verschiedenen Wildtierarten untersucht. Voraussetzung für die Durchführung der Versuche war die Handaufzucht von sechs Rehkitzen und fünf Mufflonlämmern. Den Tieren wurde zum dorsalen Pansensack eine Vormagenkanüle implantiert. Die Haltung der Tiere erfolgte in Gehegen mit natürlicher Vegetation. Den Rehen und Mufflons wurden über die Vormagenfistel ein Marker für Flüssigkeit (Co-EDTA) und ein Marker für Partikel (Chrom-markiertes Heu) verabreicht. Anschließend wurde 5 Tage regelmäßig alle 3 bis 4 h Kot gesammelt. Die Co-/Cr-Konzentrationen der mit Schwefelsäure aufbereiteten Proben wurden atomabsorptionsspektrometrisch gemessen. Die Berechnung der Retentionszeiten der Flüssigkeit und Partikel im Gastro-Intestinal-Trakt (GIT) und im Ruminoretikulum (RR) erfolgte nach Thielemans et al. (1978), nach Grovum und Williams (1973) und Lechner-Doll (1990). Derartige Untersuchungen wurden erstmals unter annähernd natürlichen Bedingungen vergleichend an Rehen und Mufflons durchgeführt. Die Gesamtverweildauer von Flüssigkeit und Partikeln im Gastro-Intestinal-Trakt war beim Reh (MRTFlüss.GIT = 18,1 ± 2,4 h, MRTPart.GIT = 23,6 ± 3,8 h) im gesamten Jahresverlauf kürzer als beim Mufflon (MRTFlüss.GIT = 22,5 ± 3,9 h, MRTPart.GIT = 36,0 ± 4,2 h). Die Partikelver, The digestibility of slowly fermentable/digestible plant material (cellulose) increases with increasing particle retention time in the forestomach of ruminants. The retention time in the gastro-intestinal-tract depends on the size of the fermentation chambers, the food intake, the saliva flow and the selective retention of food particles. The mean retention time (MRT) of fluid and particles should differ between ruminant species and, according to differences in food quality and availability, between seasons. By measuring the ingesta passage rate of roe deer, a concentrate selector, in comparison with mouflon, a grass and roughage eater, adaptation factors of these different species to the seasonally changing forage supply were investigated. A prerequisite for the trials was the hand-rearing of six roe deer fawns and five mouflon lambs. Rumen fistulas were implanted in all adult animals leading to the dorsal ruminal chamber. The animals were kept in adequate enclosures with natural vegetation. A fluid (Co-EDTA) and a particle (Cr-mordanted fibre) marker were applied to roe deer and mouflons via the rumen fistula. After marker application, faecal samples were collected every 3 to 4 hours for 5 days. Faecal samples were prepared with sulphuric acid and the Co- and Cr-concentrations were measured by atomic absorption spectrophotometry. The retention time of fluid and particle phase in the gastro-intestinal-tract and in the ruminoreticulum were calculated according to Thielemans et al. (1978), Grovum und Williams (1973) und Lechner-Doll (1990). Such investigations were carried out for the first time under natural conditions comparing roe deer and mouflons. The total retention time of fluid and particles in the gastro-intestinal-tract was for roe deer (MRTfluid GIT = 18,1 ± 2,4 h, MRTpart.GIT = 23,6 ± 3,8 h) shorter than for mouflon (MRTfluid GIT = 22,5 ± 3,9 h, MRTpart.GIT = 36,0 ± 4,2 h ) during the whole year. The retention time of particles in the ruminoreticulum was

Indien men overweegt om eigen schapen met andere schapenrassen te kruisen uit het oogpunt zo een bescheidener voedergedrag te creeren, dan dient men zich te realiseren dat andere nadelen weer binnengehaald kunnen worden

Le maintien de la diversité génétique des populations d'espèces fragiles, en voie de disparition, est un sujet primordial de la biologie de la conservation. Dans ce cadre, la compréhension des mécanismes qui vont affecter la diversité génétique au cours du temps est essentielle. Mon travail de doctorat a consisté en l'étude de la dynamique de la diversité génétique d'une population de mouflons Ovis aries, fondée en 1957 par un unique couple sur une île de l'archipel de Kerguelen (océan Indien). Durant cette étude, j'ai tout d'abord suivi les variations de l'hétérozygotie (He, évaluée à partir du typage génétique des individus à 25 marqueurs microsatellites) depuis la fondation jusqu'à 2003. J'ai montré que la valeur observée de He est supérieure à celle attendue à partir de modèles théoriques. Nos résultats, complétés par une étude par simulation, suggèrent que cette forte He pourrait être due à la sélection. Puis, pour mesurer la dérive, je me suis intéressé à la taille efficace de la population de mouflons. Malgré des conditions défavorables (démographie cyclique et système de reproduction de promiscuité caractérisé par une forte compétition entre les mâles), la dérive est apparue limitée. Mes résultats suggèrent que les variations de densité diminuent la compétition entre mâles, ce qui permet à la plupart de se reproduire, limitant ainsi la perte de la diversité génétique. La structure génétique des populations peut aussi influencer la perte de la diversité génétique. A partir d'un logiciel couramment utilisé (STRUCTURE, Pritchard et al. 2000), j'ai pu détecter une structure génétique dans la population de mouflons. Pourtant cette structure ne semble pas avoir de sens biologique et serait causée par des particularités des marqueurs génétiques utilisés. Enfin, j'ai mesuré les effets de la diversité génétique sur la valeur sélective des individus. J'ai tout d'abord pu révéler les effets négatifs de la diversité génétique et de la charge parasitaire sur la condition