Selected aspects of female white-faced saki (Pithecia pithecia) reproductive biology in captivity

Little is known regarding the reproductive biology of the white-faced saki. Although sakis have been in zoos since the mid-1970s, little attention has been paid to the reproductive biology of this threatened species. This study describes the results of a 3-year study of the reproduction of the white-faced saki in captivity. Using noninvasive methods to determine levels of estrone conjugates (E₁C) and pregnanediol-3-glucuronide (PdG) in daily urine samples, we have characterized the female reproductive cycle of this species. Nonconceptive ovarian cycles were 16.95 ± 1.57 (SD) days, gestational length was 146.1 ± 5.2 (SD) days, and the length of lactationally induced infertility varied among females but averaged 163 ± 40.6 (SD) days. Attempts to accelerate puberty by pairing a young female with an adult male was without effect. Puberty occurred at 32 months of age in one female. This study provides information that enhances our understanding of the reproductive biology of this species. © 1995 Wiley-Liss, Inc.     

Assessment of female reproductive status in captive-housed Hanuman langurs (Presbytis entellus) by measurement of urinary and fecal steroid excretion patterns

The study reports on the use of urinary and fecal hormone measurements for monitoring female reproductive status in captive-housed Hanuman langurs (Presbytis entellus). Matched urine and fecal samples collected throughout 7 complete menstrual cycles of two females, and during part of one pregnancy in a third female were analyzed. Estrone conjugates (E1C) and immunoreactive pregnanediol glucuronide (PdG) in urine and immunoreactive estradiol (E2), progesterone (P4), pregnanediol (Pd) and 20α-hydroxyprogesterone (20αOHP) in feces were measured by enzymeimmunoassay. E1C and PdG in urine were excreted in a cyclic pattern with E1C levels increasing 3- to 4-fold during the follicular phase to reach preovulatory peak values 2 days before a defined rise in PdG concentrations. Cycle lengths ranged between 20 and 34 days comprising a variable follicular phase of 7–21 days and a more consistent luteal phase of 12–14 days. High pressure liquid chromatography (HPLC) analysis of fecal extracts confirmed the presence of all fecal hormones measured, but indicated large amounts of additional immunoreactivity in the three progestin assays. The patterns of excretion of fecal E2 and all three fecal progestins corresponded well with those of steroid metabolites in urine in showing a clear and well defined follicular phase E2 rise followed by a luteal phase progestin increase. Measurement of 20αOHP immunoreactivity revealed the most stable baseline and the highest follicular/luteal phase differential. Levels of all hormones were clearly elevated during pregnancy although urinary E1C and PdG showed a more pronounced increase compared to fecal metabolites. The results indicate that urinary and fecal hormone analysis can be applied to noninvasive monitoring of reproductive status in the Hanuman langur. © 1995 Wiley-Liss, Inc.     

Naturally occurring fatal herpes simplex virus 1 infection in a family of white-faced saki monkeys (Pithecia pithecia pithecia)

A family of three white-faced saki monkeys (Pithecia pithecia pithecia) died 48-96 hours after the onset of anorexia, nasal discharge, pyrexia and oral ulceration. One animal also had clonic seizures. Lesions found post-mortem consisted of oral and esophageal ulcers, hepatic and intestinal necrosis, meningoencephalitis and sporadic neuronal necrosis. Intranuclear inclusion bodies and syncytial cells were present in oral lesions and affected areas of liver. Herpes simplex virus 1 (HSV-1) was identified as the etiology of disease by virus isolation, polymerase chain reaction, or in situ hybridization in all three animals. Immunohistochemistry for detection of apoptotic DNA and activated caspase-3 showed significant levels of apoptosis in oral and liver lesions and occasional apoptotic neurons in the brain. These findings demonstrate the vulnerability of white-faced saki monkeys to HSV-1 and provide initial insight into the pathogenesis of fatal HSV-1-induced disease, indicating that apoptosis plays a significant role in cell death.     

Application of fecal steroid techniques to the reproductive endocrinology of female verreaux's Sifaka (Propithecus verreauxi)

Solid phase extraction, high performance liquid chromatography, and radioimmunoassay were used to test the validity of fecal steroid analysis for assessing ovarian function in sifaka (Propithecus verreauxi). Daily fecal samples were collected over a 4 month period from two cycling female sifaka, and single samples were collected from females during normal gestation and males while housed at the Duke University Primate Center. Tests of radioimmunoassay validity indicated that solid phase extraction and microradioimmunoassay techniques were reliable and accurate methods for quantifying ovarian steroids in sifaka feces. The progesterone (P₄) antibody specifically quantitated only P₄, while several estrogen metabolites made small contributions to immunoreactive measures of estradiol (E₂). A 1:10 dilution reduced these contributions to 3–15% of the estimated E₂ concentration. Although the spectral data suggested that E₂ was not the major metabolite present, it accounted for the majority of the immunoreactivity at normal assay dilutions. Fecal profiles of immunoreactive E₂ and P₄ in the conceptive female resembled serum profiles of other strepsirhines. E₂ and P₄ were elevated at the end of the conceptive cycle and were more markedly increased in late pregnancy in the two pregnant females. Mating behavior and indices of sexual interest were observed in conjunction with E₂ peaks, although not all peaks were accompanied by observations of sexual behavior. © 1995 Wiley-Liss, Inc.     

Excretion of estrone,estradiol, and progesterone in the urine and feces of the female cotton-top tamarin (Saguinus oedipus oedipus)

The excretion of three gonadal steroids was studied in the urine and feces of female cotton-top tamarins (Saguinus oedipus oedipus). Each steroid, ¹⁴C-estrone, ¹⁴C-estradiol, and ¹⁴C-progesterone, was injected into a separate female cotton-top tamarin. Urine and feces were collected at 8 hr intervals for 5 days on the three tamarins. Samples were analyzed to determine the proportion of free and conjugated steroids. Steroid excretion patterns were determined by sequential ether extraction, enzyme hydrolysis, and chromatography. Labeled estrone was excreted in a slow and continuous manner into the urine (57%) and feces (43%) with 90% of the steroid conjugated. The nonconjugated form had an elution profile identical to ³H estrone, but the conjugated portion was not completely hydrolyzed by enzyme. Labeled estradiol was excreted primarily in the urine (87%) and was released rapidly. Over 90% of the injected ¹⁴C-estradiol was excreted in urine as a conjugate, of which 41% was converted to an estrone conjugate and the remaining 59% was excreted as a polar estradiol conjugate. Labeled progesterone was excreted primarily in the feces (95%), 61% of which was free steroid. Four to six individual peaks of radioactivity were found when using celite chromatography and high performance liquid chromatography (HPLC), indicating that progesterone is metabolized into several urinary and fecal metabolites. One of these peaks matched ³H-progesterone and others may be pregnanediols, pregnanetriols, and 17-hydroxyprogesterone. These steroidal excretion patterns help explain the atypical hormonal patterns seen during the tamarin ovarian cycle.     

Monitoring ovarian function in scimitar-horned oryx (Oryx dammah) by measurement of fecal 20α-progestagen metabolites

The feasibility of monitoring ovarian function in scimitar-horned oryx (Oryx dammah) by measurement of fecal 20α-progestagens was investigated. Fecal samples were collected daily or on alternate days over a 4–11 month period from five oryx during natural (n = 4) or synthetic PGF_2α (cloprostenol)-controlled (n = 1) cycles. Of the four oryx undergoing natural cycles, three had regular access to a vasectomised male, and mating dates were recorded. Ultrasonography was used to monitor changes in reproductive tract morphology in the female administered with cloprostenol. Neutral steroids were extracted from feces with methanol:petroleum ether (2:1 v/v) after first removing phenolic steroids with potassium hydroxide (1 M). The concentration of 20α-progestagens in the methanol phase was measured by enzymeimmunoassay. Excretion of 20α-progestagens in all females followed a cyclic pattern corresponding to the follicular and luteal phases of the ovarian cycle. Concentrations of fecal 20α-progestagens were on average twentyfold greater during the luteal phase compared with the follicular phase. Mean (±SD) ovarian cycle length, based on fecal progestagen profiles, was 24.4 ± 2.2 days with mean (±SD) luteal and follicular phase lengths of 18.7 ± 2.8 and 5.7 ± 1.6 days, respectively. Mating by a vasectomized male occurred when 20α-progestagen concentrations were still elevated or declining. Similarly, fecal progestagens did not return to follicular phase concentrations for 4–5 days after administration of cloprostenol, and a 4 day delay was observed between ovulation, as visualized by ultrasound scanning, and a rise in fecal 20α-progestagens. These data suggest a time lag of approximately 4 days between reproductive events and changes in fecal 20α-progestagen concentrations. We conclude that measurement of immunoreactive 20α-progestagen concentrations in feces has limited application for predicting ovulation or accurately timing inseminations because of delay in steroid excretion, but will enable noninvasive monitoring of ovarian cycles in scimitar-horned oryx for fertility assessment and for determining the outcome of artificial insemination programs. © 1995 Wiley-Liss, Inc.     

Long-term data on basic reproductive parameters and evaluation of endocrine,morphological, and behavioral measures for monitoring reproductive status in a group of semifree-ranging Tonkean macaques (Macaca tonkeana)

Cycle and gestation lengths, menstruation patterns, female genital swelling characteristics, and male-female consortship durations are reported in a semifree-ranging group of Tonkean macaques (Macaca tonkeana) studied over a 12 year period. In addition, profiles of urinary estrone conjugates (E1C) and immunoreactive pregnanediol glucuronide (PdG) throughout four complete menstrual cycles in two females and three full-term pregnancies are presented. Based on intermenstrual intervals, a mean cycle length of 37–41 days (n = 55 cycles in 10 females) was found. Gestation length averaged 173 days (n = 27 pregnancies in eight females). Measurement of PdG immunoreactivity in urine revealed a cyclic pattern with a 5–15-fold increase between follicular and luteal phase concentrations, suggesting that PdG is a reliable indicator of ovarian cyclicity and luteal function. In contrast to PdG, E1C excretion showed no clear pattern throughout the cycle; however, highest values of E1C were usually found shortly before the onset of the luteal phase PdG rise at the presumed time of ovulation. Levels of both hormones were elevated during the first half of gestation and showed a marked increase throughout the second half, with maximum E1C concentrations being up to 100-fold higher than nonpregnant levels. Consortships by the male and occurrence of female genital swelling were long lasting (on average 5–10 days and 13 days, respectively) and were restricted to the follicular phase of the cycle. The day of maximal swelling and day of detumescence as well as the end of male consortship were closely associated with the periovulatory period. Swellings and consortships were longer following lactational ammenorhea than for subsequent cycles. The evolutionary significance of the cyclical changes undergone by females upon their relations with males is discussed. © 1996 Wiley-Liss, Inc.     

Monitoring ovarian function in marmosets and tamarins by the measurement of urinary estrogen metabolites

Practical aspects of urinary estrogen analysis were considered with regard to establishing simple and reliable methods for monitoring ovarian function in marmosets and tamarins. Changes in the hormone:creatinine ratio in small volumes of urine from the common marmoset were significantly correlated with changes in 24-h excretion. Comparison of the metabolism and excretion of estrogens during the ovarian cycle in the common marmoset and cottontop tamarin revealed interesting species differences. High concentrations of conjugated estrone were measured in marmoset plasma, but estradiol 17β was the predominant estrogen in urine. In contrast, estrone was the most abundant estrogen measured in tamarin urine. Both species excreted very little estriol. Sulfates and glucuronides were present in urine in similar proportions before ovulation in the marmoset, although after ovulation sulfates were the more abundant. Conversely, most of the estrogens in tamarin urine appeared to be conjugated as glucuronides. Direct assay for estrone sulfate was applied to the measurement of urinary estrogen excretion during the ovarian cycle in a marmoset. The results compared well with those for total estradiol 17β after hydrolysis and ether extraction. The use of direct assays for conjugated estrogens in small volumes of urine is suggested as a practical method for monitoring ovarian function in marmosets and tamarins.     

Measurement of urinary and fecal steroid metabolites during the ovarian cycle in captive and wild Japanese macaques, Macaca fuscata

We measured the concentration of steroid hormones from urine, feces, and blood samples of two captive Japanese macaques, Macaca fuscata, during nonconceptive ovarian cycles to compare the patterns of the excreted steroids with those of circulating steroids. Urine and feces were analyzed for estrone conjugates (E1C) and pregnanediol-3-glucronide (PdG) using enzyme immunoassays (EIAs), while plasma was analyzed for estradiol-17beta(E2), progesterone (P), and luteinizing hormone (LH) using radioimmunoassays (RIAs). Urinary and fecal E1C and PdG levels were approximately parallel to plasma E2 and P levels, respectively. The E1C profiles of daily urinary and fecal samples revealed a midcycle peak, followed by a sustained PdG increase lasting up to two weeks from the E1C peak. A fecal E1C peak was one day later than the urinary E1C peak. One of the captive females exhibited a discrete plasma LH peak, one indicator that ovulation has occurred, on the day following the urinary E1C peak, i.e., the same day of fecal E1C peak. We measured excreted steroids in nine wild females and determined the timing of ovulation by comparing fecal steroid profiles to those obtained in captive monkeys. Data from wild females indicated that eight of nine females conceived during their first ovulatory cycle of the sampling period, whereas the remaining female failed to conceive during the sampling period even though she ovulated. In the eight females that conceived, E1C increased again following the detected or estimated E1C peak, with levels comparable to the preovulatory peak levels, and sustained elevations of PdG for over 40 days. These data illustrate that the urinary and fecal profiles of ovarian steroid excretion obtained through the application of these noninvasive techniques provide an accurate approach for monitoring conceptive and nonconceptive ovarian cycle in captive and free-living Japanese macaques.     

Endocrine monitoring of the ovarian cycle and pregnancy in the saddle-back tamarin (Saguinus fuscicollis) by measurement of steroid conjugates in urine

Direct measurements of urinary immunoreactive estrone conjugates (E1C) and pregnanediol glucuronide (PdG), were applied to monitoring the ovarian cycle (n = 9) and pregnancy (3 full term pregnancies, 2 mid-term abortions) in Saguinus fuscicollis. During the ovarian cycle, urinary E1C concentrations revealed a high degree of day-to-day variability and appeared to be uninformative in reflecting cyclic ovarian function. In contrast, PdG was a reliable indicator of ovarian cyclicity with excretion patterns corresponding well with plasma progesterone profiles. Luteal phase PdG concentrations were on average 4–7–fold higher than corresponding follicular phase values. On the basis of changes in circulating progesterone, a mean cycle length of 25.7 ±1.0 days with an average follicular phase of 7.1 ± 0.6 days and a mean luteal phase of 18.6 ± 0.7 days, was found (n = 14 cycles). Following conception, both urinary steroid conjugate concentrations increased and elevated levels were maintained beyond the normal luteal phase length, allowing pregnancy to be determined at around day 25–30. During mid- to late pregnancy, PdG levels declined while E1C concentrations continued to be elevated until approximately 6 weeks before parturition when a decrease occurred. Both hormones showed a clear and rapid fall to follicular phase values following termination of pregnancy at either parturition or mid-term abortion. Post partum ovulations (n = 5) occurred on average 17–18 days following birth with four ovulations leading to conceptions. The results demonstrate the potential of urinary steroid conjugate analysis as a practical and reliable method for non-invasive monitoring of reproductive status in the female saddle-back tamarin. © 1995 Wiley-Liss, Inc.     

Ovarian cycle approach by rectal temperature and fecal progesterone in a female killer whale,Orcinus orca

This study aimed to validate the measurements of body temperature and fecal progesterone concentrations as minimally invasive techniques for assessing ovarian cycle in a single sexually mature female killer whale. Rectal temperature data, fecal and blood samples were collected in the dorsal position using routine husbandry training on a voluntary basis. The correlations between rectal temperature and plasma progesterone concentration and between fecal and plasma progesterone concentrations were investigated. Fecal progesterone metabolites were identified by a combination of high‐performance liquid chromatography and enzyme immunoassay. Plasma progesterone concentrations (range: 0.2–18.6 ng/ml) and rectal temperature (range: 35.3–35.9°C) changed cyclically, and cycle lengths were an average (±SD) of 44.9±4.0 days (nine cycles) and 44.6±5.9 days (nine cycles), respectively. Rectal temperature positively correlated with the plasma progesterone concentrations (r=0.641, P<0.01). There was a visual trend for fecal progesterone profiles to be similar to circulating plasma progesterone profiles. Fecal immunoreactive progestagen analysis resulted in a marked immunoreactive peak of progesterone. The data from the single killer whale indicate that the measurement of rectal temperature is suitable for minimally invasive assessment of the estrous cycle and monitoring the fecal progesterone concentration is useful to assess ovarian luteal activity. Zoo Biol 30:285–295, 2011. © 2010 Wiley‐Liss, Inc.     

Assessment of ovarian function in the African elephant (Loxodonta africana) by measurement of 5α-reduced progesterone metabolites in serum and urine

We have previously shown that 5α-pregnane-3,20-dione (5αDHP), and 5α-pregnane-3-ol-20-one (5α-P-3-OH) are the major luteal and circulating progestins in the African elephant. Therefore, the aim of the present study was to determine (1) circulating levels and patterns of secretion of 5α-DHP in relation to progesterone (P4) throughout the ovarian cycle, (2) the presence and relative abundance of 5α-reduced progestins in urine and (3) whether their measurement in urine would provide a non-invasive method for monitoring luteal function. Urine samples were collected weekly throughout a total of 13 ovarian cycles from 5 females. In addition, matched blood samples were collected during 6 cycles from 2 of the 5 animals. All hormone measurement, were carried out by enzymeimmunoassay following extraction. Urine was hydrolyzed prior to extraction. Profiles of P4 and 5α-DHP in serum followed a similar cyclic pattern and both measurements were significantly correlated (r = 0.78–0.98, mean 0.89, P < 0.001). Concentrations of 5α-DHP were, however, 10–20 fold higher than those of P4. I addition, 5α-DHP measurements showed a more pronounced luteal phase increase than that of immunoreactive P4. HPLC co-chromatography confirmed the presence of large amounts of 5α-P-3-OH in urine as a single immunoreactive peak, whereas 5α-DHP was present in very low levels and measurable only as one of several immunoreactive substances. Measurements of urinary 5α-P-3-OH were significantly correlated to serum 5α-DHP measurements in each of the 6 cycles (r = 0.72–0.93, mean 0.81, P < 0.001), whereas correlation coefficients between urinary and serum 5α-DHP values were generally lower (r = 0.34–0.83, mean 0.69) and significant in only 4 of the 6 cycles. Accordingly, only urinary excretion of 5α-P-3-OH, but not of 0.15–0.20 μ/mg Cr in the follicular phase and 10-fold elevated levels (1.8–2.2 μg/mg Cr) in the luteal phase. Based on the intervals between successive luteal phase increases in urinary 5α-P-3-OH, a mean cycle length of 14.1 ± 1.8 weeks, comprising a follicular phase of 5.0 ± 0.9 weeks and a luteal phase of 9.1 ± 1.4 weeks was determined for the 13 cycles studied. The results indicate that measurements of 5α-P-3-OH in urine provide a reliable non-invasive method for monitoring luteal function in the African elephant. Zoo Biol 16:273–284, 1997. © 1997 Wiley-Liss, Inc.     

Monitoring ovarian cycles and pregnancy in brown brocket deer (Mazama gouazoubira) by measurement of fecal progesterone metabolites

In the present study, pregnancy and the estrous cycle were monitored in captive brown brocket deer (Mazama gouazoubira) by measuring fecal progestagens with a commercial enzyme immunoassay (EIA), along with behavioral data. Fecal samples were collected twice a week during pregnancy and daily during the estrous cycle and post-partum period. It was possible to distinguish between inter-luteal and luteal phases of the estrous cycle. Behavioral estrus corresponded with low concentrations of fecal progestagens. Samples from two consecutive cycles were available from five hinds, and the mean estrous cycle (n=10) was 26.9+/-1.7 d (mean+/-S.E.M.). However, when two extreme cycles (34 and 37 d) were deleted, the mean estrous cycle was 24.7+/-1.2 d. Three animals became pregnant (gestation ranged from 208 to 215 d). After fertile breeding, progestagen concentration in these hinds remained among luteal phase concentrations throughout pregnancy, with the exception of a few peaks. Within 4 d post-partum, two hinds reached interluteal phase values, while one hind maintained luteal concentrations for at least 1 week.     

Monitoring the reproductive status of Japanese monkeys (Macaca fuscata) by measurement of the steroid hormones in fecal samples

The menstrual cycles as well as the pregnancy in female Japanese monkeys (Macaca fuscata) were monitored by measuring the fecal estradiol concentrations and relative amounts of fecal progesterone. Steroids from fecal samples were extracted by using a previously developed simplified two-step method and then measured by radioimmunoassay. We successfully demonstrated that the two-step method is effective and convenient for monitoring the reproductive status of Japanese monkeys.     

Steroid metabolism and validation of noninvasive endocrine monitoring in the African wild dog (Lycaon pictus)

The purpose of this study was to validate noninvasive endocrine monitoring techniques for African wild dogs (Lycaon pictus) and to establish physiological validity of these methods by evaluating longitudinal reproductive-endocrine profiles in captive individuals. To determine the primary excretory by-products of ovarian steroid metabolism, [¹⁴C]-progesterone and [³H]-estradiol were co-administered to a female and all excreta were collected for 80 hr postinjection. Radiolabel excretion peaked ≤ 18 hr postinfusion, and progesterone and estradiol metabolites were excreted in almost equivalent proportions in urine (39.7 and 41.1%, respectively) and feces (60.3 and 58.9%, respectively). Most of the urinary metabolites were conjugated (estradiol, 94.3 ± 0.3%; progesterone, 90.4 ± 0.5%), so that immunoassays for pregnanediol-3α-glucuronide (PdG) and estrogen conjugates (EC) were effective for assessing steroid metabolites. Two immunoreactive estrogens (estradiol and estrone) and at least one immunoreactive progesterone metabolite (3α-hydroxy-5α, pregnan-20-one) were detected in feces. Urine and fecal samples were collected (1–3 times per week) for 1.5 yr from one adult female and two adult males to assess longitudinal steroid metabolite excretion. Overall correlation of urinary PdG to matched, same-day fecal progesterone metabolites immunoreactivity was 0.38 (n = 71, P < 0.05). Similarly, urinary EC was correlated (P < 0.05) with same-day fecal estrogen immunoreactivity (r = 0.49, n = 71). During pregnancy and nonpregnant cycles, copulation occurred at the time of peak (or declining) estrogen metabolites and increasing progesterone metabolites concentrations. Estrus duration was 6–9 days and gestation lasted 69 days with parturition occurring coincident with a drop in progesterone metabolites. Males exhibited seasonal trends in fecal testosterone excretion with maximal concentrations from July to September coincident with peak mating activity. Although these limited longitudinal hormone profiles should be interpreted cautiously, noninvasive gonadal steroid monitoring suggests that: (1) both female and male wild dogs may exhibit reproductive seasonality in North America, (2) females are monoestrous, and (3) peak testicular activity occurs between August and October coincident with mating behavior. From a conservation perspective, noninvasive endocrine monitoring techniques should be useful for augmenting captive breeding programs, as well as for developing an improved understanding of the physiological mechanisms underlying reproductive suppression in response to social and ecological pressures. Zoo Biol 16:533–548, 1997. © 1997 Wiley-Liss, Inc.     

Monitoring ovarian cycle and conception by fecal progesterone analysis in sika deer

The ovarian cycle and conception of sika deer were studied to reveal factors responsible for delayed conception. Concentration of progesterone in feces from 12 female Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884) was measured during the mating season in 2000. The cyclic pattern of fecal progesterone synchronized with estrous symptoms, which could hence be interpreted as indicating ovarian cycle. All observed females ovulated by 14 October. However, during the early mating season, females did not permit copulation at ovulation, and the length of luteal phase following ovulation without estrus was 9.8±4.6 days (5–24days). Most females conceived at the first copulation, which were confirmed by progesterone profiles that was sustained at a high level after the copulation. This indicates the presence of a functional corpus luteum, a state of pregnancy. Thus, some females had repeated ovulation without copulation several times, creating a 3–4week variation in the timing of conception. But some females conceived very late in the mating season after the repetition of ovulation and copulation.     

Urinary immunoreactive estrogen and pregnanediol-3-glucuronide during the normal menstrual cycle of the female lowland gorilla (Gorilla gorilla)

Urine samples were taken daily during 22 menstrual cycles of six normal adult female gorillas. Urine was analyzed for total immunoreactive estrogens (E_t) and pregnanediol-3-glucuronide (PdG) and indexed by creatinine (Cr). An average cycle length of 32 ± 1 days (mean ± SE) with a range of 25–42 days is reported. Estrogen values range from 4 to 128 ng/mg Cr and show a midcycle peak and a midluteal rise. PdG values range from 0.01 to 2.4 μg/mg Cr and display a low, flat follicular phase followed by a luteal elevation. The follicular phase is 19.5 ± 1 days in length (range 11–30 days) and accounts for the variation in cycle length. The luteal phase is 12.3 ± 0.3 days long (range 10–14 days). In contrast to previous studies, PdG levels rise two days before the estrogen peak. The results from the present study are compared with information available on the gorilla, chimpanzee, and human. The accuracy of various alignment methods is discussed, as well as the importance of the methods presented in this study for the captive propagation of gorillas.     

Excretion of radiolabeled estradiol metabolites in the slow loris (Nycticebus coucang)

The excretion pattern of estradiol was studied in the slow loris Nycticebus coucang) and the ring-tailed lemur (Lemur catta) in order to compare steroid excretion in two representative prosimian species. Daily urinary estrone conjugate measurements in the female loris provided little information when applied over prolonged periods. As a result of these negative data, a metabolic study was performed to determine if estrogen excretion patterns in the slow loris differed from those in the lemur, where urinary assays proved a useful tool in characterizing reproductive cycles. Radio-labeled estradiol was injected intravenously, and serial urine and fecal collections were analyzed for radiolabeled metabolites. The results of these studies demonstrate that more than 92% of the radiolabel was excreted in the feces of the loris, in contrast to only 16% excreted in the feces of the lemur.     

Non-invasive assessment of reproductive status in Chinese water deer (Hydropotes inermis): Correlation with sexual behaviour

The annual reproductive cycle of Chinese water deer (Hydropotes inermis), a nearly threatened small cervid species, was studied by means of fecal steroid analysis coupled with behavioural observations. Data showed a clearly seasonal reproductive pattern. In adult males, the onset of androgen secretion, in October, was concomitant with the first manifestations of territoriality. Androgen metabolites concentrations reached significant peak values in December, when matings occurred. In mature females, there was a close synchrony in reproductive states: lactational/seasonal anoestrus from June to November, pregnancy from December to May. Fecal progesterone metabolites profiles suggested that silent ovulations occurred at the onset of breeding season and that females conceived at their first ovulation with behavioural estrus. The female sexual receptivity state might last only a few hours. High levels of sniffing, parades and pursuits, concomitant of the highest concentrations of androgen, could allow the males to detect the furtive estrus in the females present in their territory. We concluded that the non-invasive method applied for the first time in this species was useful for the evaluation of the endocrine status and its relation with behaviour.