Theriogenology wild最新文献

Animal capture is essential in conservation and management programs, both for captive and wild species. This paper describes the effect of midazolam sedation in domestic and wild phasianids with respect to dorso-abdominal massage for obtaining semen samples, and on the quality of the sperm thus collected. Three experiments were performed. Experiment 1 - Determination, with respect to semen quality, of the optimum midazolam treatment for sedation in the domestic chicken. This involved sedating birds with either: 1) 2 mL of saline (control [C]), 2) 2 mg/kg of midazolam (low dose [LD]), 3) 6 mg/kg of midazolam (high dose [HD]), or 4) 6 mg/kg of midazolam and waiting 10 min before starting to massage (HD-10) (all performed in duplicate). The response time to the sedative (T1) was recorded, as were the times from the start of massage to ejaculation (T2) and its end (T3). The proportion of animals that showed stress during massage was noted via their waking, wing flapping, and the heterophil-lymphocyte ratio. The volume of all sperm samples obtained was determined, along with sperm concentration, motility, viability, and DNA integrity. Experiment 2 - The same determinations were made in captive red-legged partridges. Experiment 3 - The effect of the discovered optimum conditions (HD-10) for the above species was examined in the capercaillie (a wild species). Sperm quality was not affected by sedation with midazolam in any of the examined species, although the capercaillies and partridges were more nervous during semen collection than were the chickens.

Mammals are categorized along an altricial-precocial spectrum based on degrees of neonatal development. Altricial neonates are immature at birth and dependent on care, whereas precocial neonates are relatively well developed and independent post-partum. The Eurasian beaver (Castor fiber) is a large, semiaquatic, relatively precocial mammal in the order Rodentia. However, the extended care of kits in burrows begs the question of why beavers have precocial characteristics. A study of fetal development might enable understanding of the traits that are significant for neonatal survival. The present study examined external morphological characteristics, external biometry and the development of internal organs in 80 Eurasian beaver fetuses (crown-rump length [CRL], 2.5–19.3 cm) derived from 33 wild pregnant females hunted in Norway (33 gestational age). We also created equations to predict fetal ages from biometric parameters based on a linear relationship between biometric parameters and fetal ages estimated from fetal weight. Fetal features appeared in the following chronological order; eyelid bulbs and tactile hairs (CRL ≥ 7.3 cm), outer ears, claws, skin differentiation (CRL ≥ 8.9 cm), and hair coverage and tooth eruption (CRL ≥ 9.4 cm). All biometric parameters increased linearly and positively as the CRL increased and did not tend to stabilize. Notably, slopes of hindfoot parameters were higher than those of forefeet, suggesting that the hindfeet of beavers grow faster than forefeet, as they do in other semi-aquatic mammals. Our calculations revealed that dorsal length, CRL, thoracic and abdominal circumferences were candidate predictors of fetal age due to a high coefficient of determination (≥ 0.95) and broad range (≥ 10 cm). Our findings revealed that beaver growth was precocial in terms of differentiated skin, hair coverage, and tooth eruption, but not fully completed, as none of the fetuses had open eyes. The rapid growth of the hindfoot and some precocial traits (skin and hair differentiation) may be involved with the ability of neonatal beavers to move in water.

Assisted reproductive technologies (ARTs) have been proposed as a potential complementary strategy to other conservation efforts aimed at addressing the pressing challenges associated with managing endangered species. The Equidae family belongs to the order Perissodactyla and comprises various species, including domestic horses, donkeys, wild asses, zebras, and the Przewalski's horse, all of which belong to the genus Equus. Unfortunately, numerous subspecies of this order have become extinct in recent centuries, and many extant species are currently at risk of extinction. Recent decades have witnessed considerable progress in in vitro technologies, particularly in the domestic horse, including gamete collection and cryopreservation, as well as the successful production of embryos through in vitro fertilization techniques and cloning. Furthermore, some progress has been made in domestic donkeys and other wild equid species. However, for the majority of endangered species, effective ARTs protocols are not yet available. This review summarizes the main advances made in in vitro assisted reproductive technologies and genetic conservation efforts in equids and discuss the challenges and future prospects of these technologies in the context of wild equid conservation.

Whooping cranes (Grus americana) are naturally seasonal breeders and rely on wetland habitats throughout the annual cycle. However, captive cranes are commonly housed in dry outdoor pens, which may lack key environmental stimuli that in turn compromise reproduction. Our study sought to first, assess seasonal patterns of reproductive hormones in successful versus non-successful bird pairs and second, determine endocrine responses to alterations in enclosure environments. Fecal samples were collected from eight crane pairs year-round for 3 consecutive years, once a week during non-breeding season and three times a week during the breeding season. During Year 1, all pairs were housed in traditional dry pens, whereas during January of Year 2 all pairs were moved to either new dry pens (control, n = 4) or ponded pens (wetland, n = 4) and remained in the same pen until the end of the study. Fecal samples were assessed for gonadal (year-round) and adrenal (breeding season only) hormones. Estrogen and progestagen metabolite concentrations were low during non-breeding season in all females. However, as birds transition into a breeding season, gonadal hormone concentrations significantly increased (p < 0.001) in laying females but not in non-laying individuals. Androgen metabolite concentrations during breeding seasons were higher (p < 0.001) in males paired with non-laying females, with no variations observed during non-breeding months and within birds of the same reproductive output. We observed significant effect of enclosure environment on ovarian function of female whooping cranes. Specifically, mean estrogen metabolite concentrations increased after birds were moved from dry pen to wetland enclosures (Year 1: 349.1 ± 83.4 ng/g feces; Year 2: 382.7 ± 82.9 ng/g feces; Year 3: 556.5 ± 85.4 ng/g feces, p = 0.008 and 0.019 respectively,), whereas those of the control females remained constant. Further, estrogen concentration assessed during breeding season of Year 3 in females housed in wetland pens was higher than birds housed in a dry pen (556.5 ± 85.4 vs 311.7 ± 85.12 ng/g feces; p = 0.019). The number of eggs laid increased in three of the four pairs housed in the wetland pens, while there was no change in egg production in control birds (9 vs. 2 combined number of eggs produced by all pairs in each respective group in Year 3). Finally, moving birds to an enclosure that mimic natural environment did not impact androgen or glucocorticoid excretion. The findings demonstrate that differences in gonadal hormone production between laying and non-laying whooping crane females exist primarily during the breeding season, and that a more natural environment can have a positive influence on ovarian function in female whooping cranes.

Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) are important estrogen precursors, secreted mainly by the adrenal cortex. At late gestation, both DHEA and DHEAS (DHEA(S)) are produced at high concentrations in some species due to the developing fetal adrenal gland. Failure in DHEAS increase during late gestation can indicate fetal death, which prompts its use as a biomarker of pregnancy and fetal health in wildlife. Here, we review the most common non-invasive biomarkers of reproduction in wildlife, the molecular mechanisms of DHEAS synthesis and action during gestation, in addition to the advantages and limitations of incorporating DHEA(S) in these studies. Using previously published data, we tested the specificity and sensitivity of fecal DHEAS as a predictor of successful gestation in four captive primate species (orangutans (Pongo pygmaeus), siamangs (Symphalangus syndactylus), Japanese macaques (Macaca fuscata), and howler monkeys (Alouatta caraya)). Using data from non-pregnant/non-lactating females, we set a threshold on fecal DHEAS levels for detecting successful pregnancy per species, controlling for age and housing condition (social vs single). We found that DHEAS had 100% specificity for all species (non-pregnant samples were below the threshold for pregnancy), and 100% sensitivity for Japanese macaques housed individually, and for orangutan and siamangs (all samples from successful pregnancies were above the threshold, and all samples from stillbirth were below the threshold). However, the sensitivity was 80% in howler monkeys and 50% in Japanese macaques housed socially. Our preliminary results indicate that, while DHEAS is a promising biomarker of fetal health, it is limited to late gestation and to some species. We suggest increasing the sample size to calculate the pregnancy threshold per species and to test multiple samples from the same individual when using this method.

Male reproductive cycles in lizards can be continuous or seasonal depending on the environmental conditions and female availability. The aim of this study is to investigate whether adult males of the psammophilus lizard Liolaemus cuyanus present seasonal changes of reproductive traits throughout the reproductive cycle. In order to carry out this task, sampling of specimens (N = 27) was carried out monthly from October to March in Valle de Matagusanos, Ullúm, San Juan, Argentina (31°06′46.08′’ S, 68°38′03.84′’ W; altitude: 945 m), a semi-arid zone. The animals captured in different months were grouped based on reproductive criteria according to three relevant periods: pre-reproductive (PrR), reproductive (R) and post-reproductive (PsR). In order to identify and characterize these periods, several male reproductive traits were obtained, like morphometric parameters (body mass, snout-vent length, testes and abdominal fat body mass), tubular surface and estimation of the interstitial tissue coverage, combined with histological and cell seminiferous tubule observations (germ cells types, histological and ultrastructural details) and presence of sperm in the cauda epididymis. During the PrR period, which occurred during spring, well-developed testes with free tubular sperm cells were present, but these were less frequent than during the R period. On the other hand, luminal sperm cells were evident at the seminiferous tubules from the beginning of the R period, in conjunction with the maximum testes mass and seminiferous tubular surfaces. This was also coincident with a higher abundance of sperm cells in the cauda epididymal lumen. At the end of this period, the initial regression of the seminiferous epithelium was corroborated by organelle regression which was observed in the ultrastructure of spermatogenic cells. At the beginning of the PsR period, before autumn, a marked decrease in male reproductive traits above described was detected. Instead, an increase in abdominal fat body mass could be observed indicating the onset of the lethargy period. The results obtained suggest that this population of L. cuyanus has a seasonal reproductive cycle, with its reproductive activity occurring during the spring-summer months (PrR-R periods) and finishing in late summer (PsR).

Artificial insemination (AI) can aid conservation of African wild dogs (AWD), but methods to determine the appropriate timing of AI in females are not feasible without immobilization. This study determined whether certain behaviors coupled with fecal estrogen (fEM) and progestogen (fPM) metabolite concentrations, could be used as non-invasive parameters to predict the fertile period in female AWDs. Behavior was observed in three alpha females before, during and after the mating period, and feces analyzed for hormone metabolites. During the periovulatory period, females were immobilized 2–3 times to evaluate vulvar condition, blood hormone concentrations and vaginal cytology, and to conduct vaginoscopy. Late estrus (fertile period) could be distinguished from pro-estrus, early estrus, and diestrus using behavior; with a 2- to 5-fold higher rate of male-female affiliative behavior, sexual and non-sexual follow, alpha male initiating behavior, ride-up and copulation (P ≤ 0.05). Sexual behaviors, and male-female resting patterns declined significantly or ceased the day after last mating. Two females showed a 2.5- to 3-fold increase in fPM concentrations during late estrus compared to the pro-estrus period (P ≤ 0.05) and elevated fEM levels that rose in pro-estrus, declined to baseline by late estrus. The one anovulatory female showed no distinct pattern in fPM or fEM concentrations. Vaginal cytology and vaginoscopy could not discriminate between different phases. In summary, behavioral observations coupled with rising fPM and declining fEM can determine the fertile period in African wild dog females, whereas infrequent measurement of blood hormone concentrations, vaginal cytology and vaginoscopy are unreliable.