Faecal glucocorticoid metabolites and alarm calling in free-living yellow-bellied marmots.

When individuals of a variety of species encounter a potential predator, some, but not all, emit alarm calls. To explain the proximate basis of this variation, we compared faecal glucocorticoid metabolite concentrations in live-trapped yellow-bellied marmots (Marmota flaviventris) between occasions when they did and did not emit alarm calls. We found that marmots had significantly higher glucocorticoid levels when they called than when they did not call, suggesting that stress or arousal may play an important role in potentiating alarm calls. Marmots are sensitive to variation in the reliability of callers. The present finding provides one possible mechanism underlying caller variation: physiological arousal influences the propensity to emit alarm calls.

Long-term suppression of fertility in female giraffe using the GnRH agonist deslorelin as a long-acting implant.

Zoological institutions provide an environment conducive to studying proximate mechanisms influencing reproduction that can provide guidance to both field and captive settings seeking to manage their stock. Both national parks and zoos have space limitations that sometimes require the use of reversible contraception in order to reduce reproductive rate or limit specific individuals from reproducing. We designed a study to test the efficacy of a long-lasting contraceptive in female giraffe by monitoring reproductive endocrinology and behavior. We implanted two animals with the GnRH agonist deslorelin and monitored their endocrine status using fecal steroid analysis. We have previously validated an assay for fecal pregnanes and here we report our validation for fecal estrogens. Both sex steroid concentrations were suppressed in two females, although one female exhibited an immediate post-implantation positive feedback response. Sexual activity nearly disappeared in one animal, whereas the other showed regular sexual behavior. The contraceptive effect lasted for at least 472 d, and successfully suppressed estrous cyclicity in one female for >2 y. We conclude that deslorelin implants provide a minimally invasive means for long-term suppression of reproduction in female giraffe.

The effect of long non-reproductive periods on the genital health in captive female white rhinoceroses (Ceratotherium simum simum, C.s. cottoni).

White rhinoceroses suffer from a low reproductive rate in captivity. Intensive efforts to propagate specifically the northern white rhinoceros have been very limited. The dismal outlook for this subspecies in the wild makes successful ex situ breeding programs paramount. In this context, this study examined 48 southern and 6 northern white rhinoceroses using ultrasound and faecal hormone analysis to elucidate causes for female reproductive failure and to determine whether long non-reproductive periods have a detrimental impact on genital health. Results showed that 76% of the nulliparous females had intact hymenal membrane indicating these females had never been bred, at an age when their wild counterparts have delivered multiple offspring. Fifty-six percent of the studied population had various reproductive pathology. Cystic endometrial hyperplasia; leiomyomas of the cervix, uterus and ovary, adenoma; para-ovarian cysts and hydromucometra represent the scope of lesions identified. The stages of the lesions in nulliparous females correlated with age (r = 0.4, P < 0.05). Due to the severity of the lesions, 28% of the study population was considered post-reproductive. Therefore, the reproductive life span in some individuals was 10-20 years shorter than expected. However, in parous females the incidence of pathological lesions was significantly lower (P < 0.0001). Seventy-eight percent females studied had erratic or absent luteal activity. The hormone data corresponded with two ultrasonographic levels of ovarian activity, active and inactive, occurring within an age range of 3-19 years and 15-38 years, respectively. This suggests the lack of ovarian activity by reproductive mid-life in non-reproducing females. The accuracy of the ultrasound findings was validated by necropsy in nine animals showing a strong positive correlation (r2 = 0.9, p < 0.001). Our data suggests that the development of reproductive pathology and ovarian inactivity in white rhinoceros is an age-related consequence of long non-reproductive periods. This asymmetric ageing process of the genital organs can be prevented with the achievement of at least one pregnancy.

Fecal steroid analysis of female giraffe (Giraffa camelopardalis) reproductive condition and the impact of endocrine status on daily time budgets.

Gestation and lactation can impose substantial energetic costs on female mammals. We developed a non-invasive means to determine reproductive condition in female giraffe using fecal steroid analysis. Giraffe may be especially challenged during their reproductive cycle because of two characteristics: they are impregnated while lactating and they do not breed seasonally. We studied the social behavior and endocrinology of seven female giraffe in a large naturalistic outdoor enclosure in order to chart connections between maternal physiology and behavior across the reproductive cycle. We found that giraffe gestation averages 448 days among females producing a calf that survived, with fecal pregnane concentrations reaching a zenith during the last trimester of pregnancy. Resumption of ovarian cyclicity following parturition was accelerated after neonatal calf mortality, but ovarian cycles resumed as early as 39 days postparturition while nursing. Although time spent feeding was unaffected by reproductive state, pregnant females significantly reduced time allocated to social behavior and had a tendency to locomote less than when cycling or acyclic. We suggest that modifications in foraging strategies as a function of reproductive state among wild giraffe derive from antipredator activity rather than from metabolic demands. Female giraffe probably cope with simultaneous lactation and gestation by producing high quality milk for neonatal calves commensurate with slow fetal growth and accelerating fetal growth simultaneous with weaning of nursing calves.

Reproductive soundness of captive southern and northern white rhinoceroses (Ceratotherium simum simum, C.s. cottoni): evaluation of male genital tract morphology and semen quality before and after cryopreservation.

White rhinoceroses suffer from a low rate of reproduction in captivity. This study examines the role of male reproductive function as a contributing factor. We used ultrasonography to image accessory sex glands, testis and epididymis. Electroejaculation provided 36 ejaculates from 21 rhinoceroses. Based on the percentage of progressively motile spermatozoa, semen was categorized in three groups, high (I: >75%), intermediate (II: 50-70%) or low (III: <50%) quality. Only 52% of the males showed high semen quality. Ejaculates in the high motility category also had the highest proportion of morphologically intact spermatozoa. Both semen parameters, sperm motility and morphology, were found to positively correlate with size of the accessory sex glands. The semen category was associated with group size suggesting that the social status influenced functional reproductive parameters. Change of territorial status (n = 1) improved semen quality. Testicular fibrosis was characterized as a sign of reproductive ageing in all males older than 15 years of age (n = 13); although, this ageing process did not notably affect semen parameters. Furthermore, for the benefit of assisted-reproduction and genetic banking programs protocols for the storage of cooled semen and the cryopreservation of spermatozoa were designed using different cryodiluents. This report provides basic data for the evaluation of reproductive components and of breeding management in male rhinoceros. Our results indicate that low rate of reproduction in captivity can be attributed to reduced male reproductive fitness. Changes in management of white rhinoceroses may positively affect male reproductive function.