Seasonal Breeding Patterns Research Articles

Captive Breeding Reveals Insights Into the Ecology and Reproductive Biology of 11 Little-Known Malagasy Frog Species.

Amphibians are facing an extinction crisis, with ex situ programs increasingly being used as a tool for their conservation. However, conservation efforts are often limited because we do not understand the ecological, behavioral, and life history traits of many amphibian species. Here, we report on the seasonal breeding patterns, egg-laying behavior, clutch size, and development of 11 frog species maintained at a conservation breeding facility in Andasibe, Madagascar. The frogs exhibited diverse breeding strategies aligned with life history theory. Counting the eggs in 1239 egg masses across these 11 species, we found endotrophic microhylids and terrestrial-breeding species had the smallest clutch size yet completed metamorphosis quickly, whereas species that laid eggs above or in water with exotrophic larvae had larger clutch sizes and took longer to develop. Most reproduction in captivity occurred during the warm, rainy season and followed seasonal patterns in temperature variation. Yet, Mantidactylus betsileanus bred throughout the year, and Heterixalus betsileo required additional environmental stimuli to trigger reproduction. Notably, we confirmed that Gephyromantis mitsinjo lays eggs on land with tadpoles developing terrestrially within jelly, a behavior previously theorized but which until now remained unobserved. Such observations show how captive breeding programs can be used to gain valuable data on the life history traits of species that are otherwise challenging to observe in nature. Our findings can be used to assess threats to closely related species, helping inform conservation efforts in a country harboring exceptional amphibian species richness and endemism.

Comparative analysis of breeding patterns and reproductive efficiency of mares in subtropical conditions of Pakistan.

The present study aimed to evaluate and compare the overall and breed-specific seasonal breeding patterns, fertility rates, cyclicity, and follicular dynamics of Arab, Thoroughbred, and Percheron mares under the subtropical conditions of Pakistan. A retrospective analysis of climatic data and breeding records of eleven breeding studs spanning four years (2020-2023) was made to find out the overall seasonality in the breeding pattern of mares. Fifty mares of each breed (n=150 in total) were scanned by ultrasonography for a calendar year to find the cyclicity pattern and follicular dynamics (follicular growth rate, size of ovulatory follicle, and days from estrus till ovulation). The statistical analysis of breeding records demonstrated a clear pattern of seasonal breeding (p<0.05). The highest monthly foalings were noted in March (247±45.37), and overall breeding activities peaked in Spring season (p<0.05). Breed-specific results of Arab, Thoroughbred, and Percheron mares revealed that Arab mares maintained stable breeding activity throughout the year, with the highest activity in spring and peak conception rate in winter (56.25%±32.78; p>0.05). Thoroughbred mares experienced significant seasonal declines from spring to winter with a peak conception rate in winter (63.89%±27.37, p>0.05). Percherons showed the most pronounced seasonal effects, especially with a high fall conception rate (73.04%±19.61) and a sharp decrease in winter breeding metrics (p<0.05). Furthermore, Thoroughbred and Percheron mares displayed the most pronounced seasonal effects on the percentage of cyclic mares 77.3% and 56% in winters (p<0.05). Moreover, the follicular dynamics of the three breeds also exhibited significant differences (p<0.05). The current study concludes that seasonal and breed-specific variability exists among the reproductive parameters of Arab, Thoroughbred, and Percheron mares in subtropics, necessitating breed-specific reproductive management measures to maximize mare breeding efficiency.

Protection Gains and Potential Risks: Insights from a Decade of Change of Chiru in the Arjinshan

As a migratory ungulate species, the chiru ( Pantholops hodgsonii ) primarily inhabits the Qinghai–Xizang Plateau. The population of the chiru has experienced a steady increase in recent years due to the implementation of rigorous conservation measures, including the establishment of nature reserves and legislation prohibiting hunting and killing. However, the study of chiru population ecology remains poorly understood duo to the unique and harsh natural conditions, as well as the seasonal migration and breeding patterns. In our study, we observed a higher overall population of the chiru (with average daily observations of 352 in 2012–2013 and 453 in 2023) and a demographic shift toward younger age groups (with juvenile percentage at 17.23% in 2023 and 15.85% in 2012–2013), implying the effectiveness of conservation efforts. But the marked increase in mortality rates among chiru warrants serious attention, particularly with regard to juvenile fatalities (from 1 death in 2012–2013 to 51 deaths in 2023). During past conservation efforts, the chiru population has gradually recovered; however, it is imperative to acknowledge the potential future risks due to accelerated climate change and intensification of human activity.

Administration of melatonin prior to modified synchronization protocol improves the productive and reproductive efficiency of Chinese crossbred buffaloes in low breeding season.

Melatonin is a neurohormone involving various biological processes, including restoration of cyclicity in animals with seasonal breeding patterns. The use of melatonin in different forms has gained broader acceptance in different species, particularly in summer anestrous buffaloes. The objective of the current study was to evaluate the melatonin effect on the reproductive and productive performance of crossbred buffaloes during the low breeding season. Sixty-five cyclic and reproductively sound crossbred buffaloes were randomly allocated to three groups: the G1 (n = 20) served as the control group and received no single melatonin, G2 received melatonin (n = 22; 18 mg/50 kg, body weight) once prior to synchronization and G3 group was administered multiple melatonin injections (n = 23; 6 mg/50 kg body weight) for three consecutive days before the start of the synchronization protocol. The reproductive performance, milk yield traits, and serum immunoglobulin M (IgM) and melatonin levels were evaluated in treated and untreated crossbred buffaloes. The results revealed that a single dose of melatonin administration has (p < 0.05) improved estrus response, ovulation occurrence and follicular growth in crossbred buffaloes compared to control groups. Higher pregnancy rates were observed in both melatonin-treated buffalo groups compared to the control. Following the administration of melatonin, serum IgM level increased in G2 and G3; however, an increment in melatonin level (p < 0.05) was detected in the G2 group only as compared to the control group subsequent day of melatonin administration. The milk compositions were not affected by melatonin administration except for milk urea nitrogen and somatic cell count (SCC). The melatonin administration (p < 0.05) decreased the somatic cell count in buffalo milk compared to untreated. In conclusion, single or multiple doses of melatonin before initiating the synchronization protocol improved the ovulation, ovulatory follicle diameter and pregnancy rates in crossbred buffaloes during the low breeding season. Moreover, the administration of melatonin enhanced the IgM values along milk traits in terms of milk protein, MUN and somatic cell count in treated buffaloes.

Seasonality of reproduction in Bathyergidae is a function of group size: A novel hypothesis (Rodentia)

In the African mole-rat family (Bathyergidae), species show both year-round and seasonal breeding patterns even though all species inhabit regions with varying seasonal rainfall patterns (a well-known selection driver of seasonal breeding). This short review suggests a novel hypothesis explaining why some African mole-rat species breed seasonally and others year-round. Namely, group-living African mole-rat species (with a mean colony size greater than five) exhibit an aseasonal reproduction pattern, as breeders, particularly females, possess year-round high body conditions. This is likely due to access to abundant and high-quality resources (food and water) throughout the year and reduced frequency of engaging in strenuous activities, such as digging, due to the increased efficiency of locating and retrieval of resource as a function of group size. While in the solitary and social species, with mean colony sizes of five or less, there are too few colony members to provide sufficient cooperative care benefits, the breeders show a seasonality to their body condition and thus breeding investment. As such, we hope to start a discussion on how group size could affect circannual breeding rhythms and propose some avenues for future research.

Reproduction and Fertility of Buffaloes in Nepal.

Water buffalo (Bubalus bubalis) in Nepal contributes 57% of the total milk and 36% of the total meat production in the country. The productive efficiency of Nepalese buffaloes is quite low, due mainly to subfertility and infertility. Delayed puberty and prolonged inter-calving intervals, attributed mainly by anestrus due to silent cyclicity and ovarian acyclicity, are the major forms of infertility in Nepalese buffaloes. Moreover, buffaloes in Nepal show a distinct seasonal breeding pattern, with July to December as the active breeding season, and with April to June and January to March as the low and transitional breeding seasons, respectively. Endoparasitic infection and poor nutritional status, which are more severe during the low season, are found to be the major factors causing anestrus and compromising its treatment response in buffaloes. Various hormonal protocols for timed artificial insemination (TAI) have been attempted, with a varying pregnancy outcome. Recently, an integrated technique including anthelmintic treatment, nutritional supplementation and hormone-based fertility management programs for TAI has been developed and implemented successfully. A wider adoption of this technique as a package of practices could be key to improving the reproductive efficiency of buffaloes in Nepal.

Reproductive performance and sex ratio adjustment of the wild boar (Sus scrofa) in South Korea

The wild boar (Sus scrofa), a polygynous species, rapidly expanded its geographical range and increased its population size in South Korea following the extinction of large carnivores and changes to rural environments. Understanding wild boar reproductive traits and strategies is essential for their effective management; however, studies in this area are lacking. Using samples collected from hunting bags, the relationships between 1) litter size and female weight and 2) fetal sex ratio and female body condition were examined to understand wild boar life-history strategies. Wild boars showed a seasonal breeding pattern that maximized reproduction. Litter size (mean = 5.7 ± 1.7) was correlated with female weight, whereas fetal sex ratio was not explained by female body condition. However, the heaviest ranked fetuses within the litters were male-biased. Wild boars aged three years or less accounted for 90% of the total population, and sexual dimorphism developed from two years of age. Considering that their reproductive strategy is more effective (i.e., early gestation and large litter size) than that of other polygynous species, the Trivers–Willard model was not supported for the wild boars in this study. Instead, females adjusted the sex of the heaviest fetus in the litter to maximize lifetime reproductive success.

Seasonal Dynamics of Faunal Diversity and Population Ecology in an Estuarine Seagrass Bed

Biodiversity is important for communities to be resilient to a changing world, but patterns of diversity fluctuate naturally over time. Understanding these shifts — and the species driving community dynamics — is crucial for informing future ecological research and conservation management plans. We investigated the impacts of seasonality, small-scale changes in seagrass cover, and small-scale spatial location on the epifaunal communities occupying a temperate seagrass bed in the South Island of New Zealand. By sampling epifaunal communities using a fine-mesh push net two to three times per season for 1 year, and using a combination of multivariate and hierarchical diversity analyses, we discovered that season, seagrass cover, and the location within the bay, and their interactions, explained 88.5% of the variation in community composition. Community composition and abundances, but not numbers, of species changed over seasons. The most common taxa were commercially important Caridean shrimp and juvenile flounder (Rhombosolea spp.), and both decreased in abundance in summer (shrimp: 1.40/m2 in winter to 0.80/m2 in summer; flounder: 0.15/m2 in winter to 0.01/m2 in summer). Other commercially important species were captured as juveniles, including blue cod (Parapercis colias), kahawai (Arripis trutta), and whitebait (Galaxias spp.). The only adult fish captured in the study were two pipefish species (Stigmatopora nigra and Leptonotus elevatus), which had distinctly seasonal breeding patterns, with reproductively active adults most likely to be found in the spring and fall. Our study highlights the importance of estimating biodiversity parameters based on sampling throughout the year, as some species will be overlooked. We demonstrate that the temperate estuarine seagrass-affiliated animal communities differ in response to season and fine-scale local environments, causing fluctuations in biodiversity throughout the year.

Breeding Dynamics of Gopher Frog Metapopulations Over 10 Years

Abstract Populations of amphibians that breed in isolated, ephemeral wetlands may be particularly sensitive to breeding and recruitment rates, which can be influenced by dynamic and difficult-to-predict extrinsic factors. The gopher frog Rana capito is a declining species currently proposed for listing under the U.S. Endangered Species Act, as well as one of many pond-breeding amphibians of conservation concern in the southeastern United States. To represent gopher frog breeding dynamics, we applied an occupancy modeling framework that integrated multiple data sets collected across the species' range to 1) estimate the influence of climate, habitat, and other factors on wetland-specific seasonal breeding probabilities; and 2) use those estimates to characterize seasonal, annual, and regional breeding patterns over a 10-y period. Breeding probability at a wetland was positively influenced by seasonal precipitation (Standardized Precipitation Index) and negatively influenced by fish presence. We found some evidence that the amount of suitable habitat surrounding a wetland was positively correlated with breeding probability during drought conditions. The percentage of sampled wetlands (N = 192) predicted to have breeding varied seasonally, annually, and regionally across the study. Within-year temporal patterns of breeding differed across the range: in most locations north of Florida, peaks of breeding occurred in winter and spring months; whereas breeding was more dispersed throughout the year in Florida. Peaks of breeding across the 10-y period often occurred during or in the season following high rainfall events (e.g., hurricanes). These results have direct applications for site-level management that aims to increase successful breeding opportunities of gopher frogs and other associated pond-breeding amphibians, including monitoring protocol and intensity, removal of fish, and improving terrestrial habitat conditions surrounding wetlands (e.g., via tree or shrub removal and prescribed fire). The results also have implications for better-informed management through the closer alignment of breeding activity monitoring with predicted seasonal peaks. Furthermore, estimates of breeding frequency can be incorporated into population viability analyses to inform forthcoming assessments of extinction risk and designation of the species' conservation status by the U.S. Fish and Wildlife Service.

Filling in the holes: The reproductive biology of the understudied Mahali mole-rat (Cryptomys hottentotus mahali)

African mole-rats have provided great insight into mammalian evolution of sociality and reproductive strategy. However, some species have not received attention, and these may provide further insights into these evolutionary questions. The cooperatively breeding Mahali mole-rat (Cryptomys hottentotus mahali (Roberts, 1913)) is one such species. Body mass, reproductive-tract morphometrics, gonad histology, and plasma reproductive hormone concentrations were studied for breeding and non-breeding males and females over 1 year. This study aimed to discern if this species exhibits a seasonal or aseasonal breeding pattern and whether there is a relaxation of reproductive suppression at any point in the year in non-breeding animals. The pattern of reproductive relaxation during the wetter months is similar to other African mole-rat species. Interestingly, births and pregnant breeding females were recorded throughout the year, thus indicating an aseasonal breeding strategy, despite inhabiting a region that experiences seasonal rainfall. However, there were periods of the year favouring increased reproduction to enable an increased likelihood of offspring survival. This suggests that the Mahali mole-rat may be an opportunistic breeder possibly brought about by the benefits of living in a cooperatively breeding group and potentially moving into more arid environments that were previously unexploited by the genus Cryptomys Gray, 1864.

Synergy between behavioural research on beluga whales (Delphinapterus leucas) conducted in zoological and wild settings

Behavioural observations of captive beluga whales have complemented and extended much of what has been learnt about this species in the wild. Aquarium-based research has provided finer-scale specificity for many topics, including the seasonal breeding pattern that is characteristic of this species, as well as socio-sexual behaviour that appears to be an important part of the behavioural repertoire of this species. One example is a strong propensity for male–male social interactions that begin to develop at an early age. In addition, detailed behavioural milestones in calves have been documented in ways that extend that which have been collected from wild populations. These include swim positions with mother, separations/reunions with mother, and other social interactions, and play. Characteristics of beluga maternal care have also been studied more often in captive settings than in the wild, particularly with respect to details pertaining to nursing behaviour, individual differences in maternal style and allomaternal care. Other topics that have received scientific scrutiny in zoological settings include individual differences and behavioural laterality. Thus, a greater understanding of beluga behavioural biology has the potential to emerge as a consequence of synergy between research conducted in the two settings.

Divergent Seasonal Reproductive Patterns in Syntopic Populations of Two Murine Species in Southern Spain, Mus spretus and Apodemus sylvaticus.

Simple SummaryIn temperate zones of the Earth, most species reproduce in seasons providing the most favourable environmental conditions. Producing gametes is expensive in energetical terms, so both males and females either reduce or abolish gametogenesis during the non-breeding period. We thoroughly studied the testes of sexually inactive males of two rodents, the wood mouse, Apodemus sylvaticus, and the Algerian mouse, Mus spretus, in southern Iberian peninsula. These populations are syntopic, that is, animals of the two species share their territories and resources, so one would expect them to show similar or identical seasonal reproduction patterns. Contrarily, we found that both species reproduce during most of the year, but wood mice stop breeding in the summer whereas Algerian mice do it in winter. These divergent seasonal breeding patterns imply that either very subtle animal features and/or environmental cues operate to determine reproduction timing and support the notion that multiple models of circannual reproduction patterns are possible for different populations of the same species, showing that the mechanisms controlling seasonal reproduction are in fact very plastic and fast evolving. Hence, small mammals probably have multiple ways available to get adapted to the unstable environmental conditions derived from the ongoing global climate change.In most mammals with seasonal reproduction, males undergo testis regression during the non-breeding period. We performed a morphological, hormonal, functional, and molecular study of the testes of sexually inactive males of two species of murine rodents, the wood mouse, Apodemus sylvaticus, and the Algerian mouse, Mus spretus, in syntopic populations of southern Iberian peninsula. Both species reproduce during most of the year, but wood mice stop breeding in the summer whereas Algerian mice do it in winter. Sexually inactive males of A. sylvaticus show complete testis regression with reduced levels of serum testosterone and abnormal distribution of cell-adhesion molecules. Contrarily, inactive males of M. spretus maintain almost normal spermotogenesis despite a significant reduction of androgenic function. The lack of an evident explanation for the divergent seasonal breeding patterns found in southern populations of A. sylvaticus and M. spretus, compared with northern ones, implies that very subtle species/population-specific features and/or non-conspicuous environmental cues probably operate to determine their seasonal breeding pattern. These results also support the notion that multiple models of circannual testis variation are possible for different populations of the same species, showing that the mechanisms controlling seasonal reproduction are in fact very plastic and fast evolving.

Sexual maturity, seasonal estrus, and gestation in female Indo-Pacific bottlenose dolphins Tursiops aduncus inferred from serum reproductive hormones.

Reproductive hormones in serum concentrations of progesterone, estradiol, and testosterone in female Indo-Pacific bottlenose dolphins (Tursiops aduncus, n = 12) housed in Ocean Park Hong Kong were investigated in the present study. Results showed that, onset of puberty of captive Indo-Pacific bottlenose dolphins was at 5 years while sexual maturity was at 6. Average serum progesterone concentrations in non-pregnant sexually mature individuals was 0.33 (0.25-0.97) ng/mL (interquartile), significantly higher than in immature ones 0.26 (0.25-0.38) ng/mL. This study found significant difference in serum estradiol concentrations between individuals at the onset of puberty (9.5± 1.7 pg/mL, ±SD) and not (below detection limit 9 pg/mL). A slightly seasonal breeding pattern, with progesterone values tend to be higher from February to October (0.38 [0.25-1.07] ng/mL) was inferred. During pregnancy, serum progesterone concentrations range from 10.54 ± 8.74 ng/mL (indexed month post-conception [IMPC] 0) to 25.49 ± 12.06 ng/mL (IMPC 2), and display a bimodal pattern with 2 peaks in early- (25.49 ± 12.06 ng/mL, IMPC 2) and late-pregnancy (21.71 ± 10.25 ng/mL, IMPC 12), respectively. Serum estradiol concentrations can seldom be detected in early-pregnancy and increase constantly in mid- (9.45 ± 1.83 pg/mL) and late-pregnancy (11.88± 3.81 pg/mL), with a spike (15.45 ± 6.78 pg/mL) 1 month prior to delivery. Serum testosterone concentrations elevate significantly in IMPC 7 (0.36± 0.10ng/mL) compared to other months (0.16± 0.10ng/mL) of the year. The present study provides normal concentration profiles for some reproductive hormones in female Indo-Pacific bottlenose dolphins and can contribute to the breeding monitoring of this species. Also, our study would shed further light on the reproductive physiology of small cetaceans.

Destined for Slaughter: Identifying Seasonal Breeding Patterns in Sheep and Goats in Early Babylonia

Previous articleNext article No AccessDestined for Slaughter: Identifying Seasonal Breeding Patterns in Sheep and Goats in Early BabyloniaMagnus WidellMagnus WidellUniversity of Liverpool* Search for more articles by this author PDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Journal of Near Eastern Studies Volume 79, Number 2October 2020 Article DOIhttps://doi.org/10.1086/710168 Views: 173Total views on this site © 2020 by The University of Chicago. All rights reserved.PDF download Crossref reports no articles citing this article.

Comparative assessment of the seasonal breeding patterns of the paddlefish Polyodon spathula (Walbaum, 1792) and the impact of growth tendency during winter and summer feeding

Comparative assessment of the seasonal breeding patterns of the paddlefish Polyodon spathula (Walbaum, 1792) and the impact of growth tendency during winter and summer feeding

Mismatched seasonal patterns of larval production and quality in subtropical barnacle populations along a coastal trophic gradient

The seasonal breeding patterns of a wide array of marine invertebrates are shaped by strong and deterministic environmental factors over their geographic distribution range, such as temperature or photoperiod. Whether or not such patterns will remain adaptive at more localized scales may depend on how consistent are secondary drivers controlling resource supply to parents and offspring. We address this question by examining the seasonal patterns of both the trophic state of coastal waters, and larval production and quality produced by a filter-feeding invertebrate, the intertidal barnacle Chthamalus bisinuatus, along a 150 km long trophic gradient in Southeastern Brazil. Results are consistent to previous remote sensing work showing strong seasonal variation of chlorophyll-a and particulate organic carbon concentrations, increasing 2 to 2.5 times from summer – early autumn to winter, compatible to enhanced production through vertical mixing caused by passing cold fronts. The spatial gradient was also verified and found to be consistent between seasons, but contrasts were of smaller magnitude (coefficients of variations between 15 and 35%). All reproductive parameters showed important seasonal but no spatial trends. Larval production was much higher in summer-early autumn, agreeing with previous results based on gonad development and early recruitment rate for this same species and published results for other chthamalids. However, per capita parental transfer of neutral fatty acids to larvae and larval survival without exogenous food increased 2 and 1.4 times from the breeding to the non-breeding season, respectively, indicating that coastal oceanographic processes favor larval quality when reproductive activity is lower. Given that food limitation is likely frequent in the study region, shifting from oligotrophic to mesotrophic, and that effects of larval nourishing can be carried over to benthic barnacle stages, results also suggest that the contribution of out-of-season offspring to overall recruitment may be disproportionately higher.

Timing of breeding and female fecundity of the greater bilby (Macrotis lagotis) in the temperate zone of South Australia: implications for translocations of a previously widespread species

Context Many of Australia’s threatened mammals were once widespread across the continent and present in both arid, semiarid and temperate habitats. However, data on breeding biology can be lacking for some climatic regions due to local extinctions of populations. The breeding biology of the greater bilby (Macrotis lagotis) has previously only been studied in captive colonies or free-ranging arid zone populations. Between 1997 and 2005, captive-bred bilbies were released at two sites in temperate South Australia. These populations provided an opportunity to determine whether bilbies adopt a seasonal reproductive strategy in the temperate zone, where this species has not been present since the early 1900s. Aims To determine the season of births, litter size and female reproductive potential in two free-ranging populations of the bilby in the temperate zone of South Australia. Methods Bilbies were regularly cage-trapped at Venus Bay Conservation Park and Thistle Island between August 2007 and April 2010 to obtain data on reproductive activity in both populations. Key results Births of pouch young in both populations occurred in winter (June–August), spring and early summer, but not between February and mid-May. Males had a significantly smaller mean testes size relative to head length in late summer, when breeding activity ceased. Average litter size at pouch emergence was between 1.00 and 1.47 pouch young, with females producing up to three litters per annum. The mean head length of females that successfully raised twins was significantly larger than that of females who raised a single pouch young. Conclusions The seasonal breeding pattern observed in the present study differs from that of year-round reproductive activity in captivity and the arid zone. The present study suggests that female body size influences fecundity, and that releasing large females at the start of the breeding season in temperate areas may maximise the initial rate of increase of a translocated bilby population. Implications The present study suggests previously widespread species such as the bilby can adapt their reproductive strategy to suit local conditions. Cessation of breeding in autumn, as observed in this study, has also been observed in other bandicoot species in southern Australia.

Detection of pregnancy in sheep using an ELISA for pregnancy-specific protein B.

The early detection of pregnancy and the determination of fetal numbers have economic benefits in sheep production because of the seasonal breeding patterns where missing a breeding opportunity means the loss of one productive year. The purpose of this study was to evaluate the efficacy of the B6-HRP ELISA for ovine pregnancy-specific protein B (oPSPB) measurement in the detection of pregnancy and estimation of fetal numbers in different sheep breeds. BioPRYN® ELISA assay kit was used for the detection of pregnancy in the experimental animals. Ninety-three ewes of three breeds (British Milksheep - BM, Lacaune - L and Transylvanian Racka - TR), each from three farms in Hungary, were included in the study. BM and L ewes were artificially inseminated (AI). Thirty-five days after AI, all ewes were examined by transabdominal ultrasound. The TR flock was mated naturally over a six-week period. At the end of the mating period, the ewes were similarly examined by ultrasound. Blood samples were taken from all pregnant ewes twice (35 and 65 days after AI), and serum samples were assayed by the BioPRYN test. It can be concluded that the detection of serum PSPB by ELISA is a much easier, safer, less expensive and highly accurate method for the detection of ovine pregnancy. Although some breed-related differences were detectable at 35 and 65 days post breeding, no differences in oPSPB levels were found in pregnant ewes carrying different numbers of fetuses.

Oviduct morphology and estrogen receptors ERα and ERβ expression in captive Chinchilla lanigera (Hystricomorpha: Chinchillidae)

Chinchilla lanigera is a hystricomorph rodent from South America whose reproductive biology presents particular characteristics that distinguishes it from other Rodentia species, such as low reproductive rate, seasonal breeding pattern, and long estrous cycle. Nevertheless, reproductive features in female chinchillas are still poorly investigated, with a scarce knowledge concerning the estrous cycle and the histology of reproductive organs. In this study, we investigate the morphology, histomorphometry, secretory activity, and immunolocalization of estrogen receptors ERα and ERβ in oviducts of nulliparous chinchillas, euthanized at fall season in Brazil. Follicular phase of estrous cycle of all studied animals was characterized by ovary and uterine morphology inspection, as well as vaginal cytology. Similar to other mammals, the oviduct wall of infundibulum, ampulla and isthmus was composed of mucosa, muscle, and serosa layers. Morphometric data of oviduct layers were used for identifying each oviduct segment. In the follicular phase, the oviduct was characterized by intense secretory activity, mainly in the ampulla, and expression of ERα and ERβ throughout the oviduct epithelium. Both ERα and ERβ were also detected in the connective tissue and smooth muscle cells. Our findings point out to the important role of estrogen in this female organ. Similar wide distribution of both ER proteins has been described for human Fallopian tube. Taken together, our data add to the understanding of the reproductive biology of female chinchillas, and may assist in the intensive breeding of this species and any eventual endeavor for conservation of chinchillas in the wild.

Effects of natural environment on reproductive histo-morphometric dynamics of female dromedary camel

Camel shows a seasonal breeding pattern with enhanced reproductive activity during the period of low climatic temperature, high rainfall and better food conditions. Therefore, the study was conducted to explore the underlying seasonal effects on histological dimensions of reproductive tract in adult female one-humped camel (Camelus dromedarius) kept in the natural environment of Pakistan. A total 25 reproductive tracts were collected during spring, summer, autumn and winter seasons and were analysed for histo-morphometric parameters during different environmental conditions. A significant increase in number (p<0.05) and size (p<0.05) of surface with secondary and tertiary ovarian follicles was observed in winter season. The epithelial height (p<0.05) and luminal diameter (p<0.05) of infundibulum, ampulla and isthmus of uterine tubes were also significantly increased during winter season. Moreover, significantly increased length (p<0.05) and circumference (p<0.05) of uterine cornua, increased number (p<0.001) and diameter (p<0.001) of endometrial glands with enlarged surface and glandular epithelia (p<0.001) were found in winter compared to summer season. Therefore, we concluded that quiescent ovarian follicular and uterine glandular activities are the main reason of camel low breeding during summer season.