Estrous cyclicity and reproductive success are unaffected by translocation for the formation of new reproductive pairs in captive red wolves (Canis rufus).

This study investigated possible female-related causes for inconsistent success among reproductive pairs in the zoo-based red wolf (Canis rufus) population. Females (n = 13) at seven institutions were assessed for evidence of ovulation and normal reproductive cycles through the measurement of estradiol and progesterone metabolite excretion in feces. Fecal cortisol metabolites (FCM) were also measured. Factors potentially affecting FCM and/or estrous cyclicity were recorded, including exhibit status (on vs. off), reproductive history (proven vs. unproven), copulatory behaviors (ties observed: yes or no), pregnancy/parturition (pups or no pups produced), and translocation before the observed breeding season (yes or no). No differences were observed in baseline FCM between females housed on versus off-exhibit (p = .46) or between females producing pups and those who did not (p = .19). Baseline FCM were significantly lower among females observed in copulatory ties compared to females never observed in a tie (p = .04), and tended to be higher in females translocated before the breeding season compared to females in existing reproductive pairs (p = .11), and among historically unproven females compared to proven females (p = .11). All females evaluated had an endocrine profile indicative of ovulation and among the four females translocated to be paired with a new male before the breeding season, two had successful pregnancies, producing litters. Therefore, despite observed differences in baseline FCM among factors, estrous cyclicity and reproductive success are unaffected by translocation for the formation of new reproductive pairs in the zoo-based red wolf population.

Red wolf (Canis rufus) sperm quality and quantity is affected by semen collection method, extender components, and post-thaw holding temperature.

Cryopreserving genetic resources is becoming increasingly important for species management. In the zoo-based red wolf (Canis rufus) population, inbreeding continues to increase in the absence of new founders. Through banking sperm, we preserve genetic diversity and create the ability to decrease inbreeding accumulation in the future. The quality and quantity of banked sperm can be affected by cryopreservation media and semen collection methods. This study's objectives were to further optimize semen extender used for red wolf sperm cryopreservation, investigate effects of post-thaw holding temperature, and to determine if urethral catheterization is an effective method for semen collection in this species. Semen collection via electroejaculation (EE) was performed on 39 adult red wolf males (ages 1 to 11) from 15 institutions. Urethral catheterization (UC) was attempted on a subset (n = 14) of those males, prior to EE. Thirteen different semen extenders were used for cryopreservation, which varied in osmolarity (HI or NORM), sugar source (glucose, fructose, or a combination), and cryoprotectant (glycerol or DMSO). Significant decreases in percent motility, forward progressive status (FPS), and acrosomal integrity were observed over time across all extenders (P < 0.0001). Among the extender components examined, post-thaw sperm motility and FPS were lower in DMSO versus glycerol based treatments (P < 0.005). Therefore, DMSO should be considered unsuitable as a cryoprotectant when freezing red wolf sperm. Effects of osmolarity and sugar source were minimal and temporally variable, however notably, a higher percentage of morphologically normal sperm were observed in the fructose-based extenders compared to glucose-based extenders post-thaw (P < 0.05). Additionally, post-thaw sperm motility and FPS declined more rapidly in samples maintained at 37 °C compared to samples held at room temperature (P < 0.05). Greater volumes of semen were collected using EE compared to UC (P = 0.041), and sperm samples collected using EE also had greater motility and FPS (P < 0.05). Additionally, though no gross morphological differences were observed, there were fewer sperm with intact acrosomes in the samples collected via UC (P = 0.0443). Thus, UC should not be considered sufficient for semen collection in red wolves when the desired fate of sperm is cryopreservation and/or AI. However, UC does provide an opportunity for a basic reproductive evaluation of a red wolf male.

Ultrasonographic characteristics of the reproductive tract and serum progesterone and estradiol concentrations in captive female red wolves (Canis rufus) with and without reproductive tract disease.

OBJECTIVE To describe ultrasonographic characteristics of the reproductive tract and serum progesterone and estradiol concentrations in captive female red wolves (Canis rufus) with and without reproductive tract disease. DESIGN Prospective study. ANIMALS 13 adult female red wolves. PROCEDURES Wolves with varying parity and history of contraceptive treatment were anesthetized to facilitate ultrasonographic examination and measurement of the reproductive tract and blood collection for determination of serum progesterone and estradiol concentrations in December 2011 and June 2012. Additionally, during the December evaluation, fine-needle aspirate samples of the uterus were obtained for cytologic evaluation. Measurements were compared between wolves with and without reproductive tract disease and between wolves that had and had not received a contraceptive. RESULTS 7 of 13 wolves had or developed reproductive tract disease during the study. Ranges for measurements of reproductive tract structures overlapped between ultrasonographically normal and abnormal tracts, but measurements for abnormal tracts were generally greater than those for normal tracts. The ultrasonographic diagnosis was consistent with the histologic diagnosis for reproductive tracts obtained from wolves that were sterilized, were euthanized, or died during the study. Cytologic results for fine-needle aspirate samples of the uterus and serum progesterone and estradiol concentrations were unable to distinguish wolves with and without reproductive tract disease. Reproductive tract disease was not associated with parity or contraceptive administration. CONCLUSIONS AND CLINICAL RELEVANCE The ultrasonographic images, reproductive tract measurements, and descriptions of reproductive tract lesions provided in this study can be used as diagnostic guidelines for the treatment and management of red wolves with reproductive tract disease.

A SURVEY OF DISEASES IN CAPTIVE RED WOLVES (CANIS RUFUS), 1997-2012.

Conservation efforts to preserve the red wolf (Canis rufus) have been in progress since the 1970s through the U.S. Fish and Wildlife Service Red Wolf Recovery Program and the Association of Zoos and Aquarium's Red Wolf Species Survival Plan. An ongoing part of this project has been to monitor mortality trends, particularly to look for potential genetic conditions resulting from inbreeding given the small founding population of only 14 individuals. An initial survey was conducted in the 1990s but a comprehensive assessment of the population has not been done since then. This retrospective review evaluates mortality in the population from 1997 to 2012 through analysis of gross necropsy and histology records provided by cooperating institutions that housed red wolves during the time period of interest. Of the 378 red wolves that died during this 15-yr period, 259 animals had gross necropsy records, histology records, or both that were evaluated. The major causes of neonatal death were parental trauma, stillbirth, or pneumonia. Overall, juveniles had very low mortality rates with only 12 wolves aged 30 days to 6 mo dying during the study period. The most common cause of death within the adult populations was neoplasia, with epithelial neoplasms, carcinomas, and adenocarcinomas being the most common types reported. Gastrointestinal disease was the second most common cause of death, particularly gastric dilation and volvulus, inflammatory bowel disease, and gastrointestinal perforations. These findings are in stark contrast to causes of mortality in the wild population, which are primarily due to human-related activities such as vehicular trauma, gunshot, or poisoning. Overall, the captive population has few health problems, but an increase in inflammatory bowel disease in particular warrants further investigation.

Infectious disease and red wolf conservation: assessment of disease occurrence and associated risks.

Infectious diseases pose a significant threat to global biodiversity and may contribute to extinction. As such, establishing baseline disease prevalence in vulnerable species where disease could affect persistence is important to conservation. We assessed potential disease threats to endangered red wolves (Canis rufus) by evaluating regional (southeastern United States) disease occurrences in mammals and parasite prevalence in red wolves and sympatric coyotes (Canis latrans) in North Carolina. Common viral pathogens in the southeast region, such as canine distemper and canine parvovirus, and numerous widespread endoparasites could pose a threat to the red wolf population. The most prevalent parasites in red wolves and sympatric coyotes were heartworm (Dirofilaria immitis), hookworm (Ancylostoma caninum), and Ehrlichia spp.; several red wolves and coyotes were also positive for bacteria causing Lyme disease (Borrelia burgdorferi). Coyotes had a more species-rich parasite community than red wolves, suggesting they could harbor more parasites and act as a disease reservoir. Species identity and sex did not significantly affect parasite loads, but young canids were less likely to have heartworm and more likely to have high levels of endoparasites. Continued disease monitoring is important for red wolf recovery because low levels of genetic variability may compromise the wolves' abilities to combat novel pathogens from closely related species, such as domestic dogs and coyotes.