Social and spatial relationships in captive southern white rhinoceros (Ceratotherium simum simum)

Although critical to the conservation of white rhinoceros, captive breeding has proven challenging because of the poor and irregular reproductive health of many captive rhinos, and social interactions may play a significant role. This research investigated the social and spatial relationships of two captive groups of southern white rhinoceros (Ceratotherium simum simum) by examining the frequency of companion changes, the number of space maintenance vocalizations made per hour by each reproductively mature female, and dominant/subordinate interactions. The observed captive rhinos did not change their companionships during the study. They exhibited space maintenance vocalizations and display greater than once per hour, particularly when feeding. Females housed with four calves on 0.033 km² exhibited space maintenance vocalizations more frequently (X±SE = 6.19±0.199/hr) than females housed with one calf and more space (0.06 km², X±SE = 0.55±0.182/hr) and females housed without calves and more space (0.65 km², X±SE = 1.90±0.086/hr). Wider separation of food piles and of females with young calves is suggested to reduce the interpreted spatial stress. The presence of a large number of rhinos in restricted captive space resulted in the formation of herds with dominance hierarchies that were enforced during competition for food and shade. The most subordinate rhino in each of the herds exhibited unusual behaviors such as dung‐kicking and nonestrus urine squirting, and neither has ever reproduced. Suppression of subordinate rhinos might lead to social stress that could negatively impact reproductive success. Zoo Biol 26:487–502, 2007. © 2007 Wiley‐Liss, Inc.     

Pregnancies following long luteal phases in southern white rhinoceros (Ceratotherium simum simum)

All extant species in the Rhinocerotidae family are experiencing escalating threats in the wild, making self-sustaining captive populations essential genetic reservoirs for species survival. Assisted reproductive technologies (ARTs) will become increasingly important for achieving and maintaining ex situ population sustainability and genetic diversity. Previous reports have shown that a large proportion of captive southern white rhinoceros (SWR) females are irregularly cyclic or acyclic, and that cycling females display two different estrous cycle lengths of approximately 30 or 70 days. It has been suggested that the longer estrous cycle length is infertile or subfertile, as no term pregnancies have been observed following long cycles. Here we report the achievement of two pregnancies following long luteal phases, using ovulation induction and artificial insemination with either fresh or frozen-thawed semen. One female SWR conceived on the first insemination attempt and gave birth to a live offspring. A second female conceived twice in consecutive long cycles although the first embryo was resorbed by 33 days post-insemination. A pregnancy from this female's second insemination is ongoing with expected parturition in November 2019. Whether prolonged estrous cycles in SWR are subfertile or infertile in natural breeding situations remains unclear. However, our findings demonstrate that the application of ARTs following prolonged cycles can result the successful establishment of pregnancies in SWR. Therefore, with ARTs, female SWR otherwise considered nonreproductive due to long estrous cycles may still have the potential for representation and contribution to the ex situ population.     

Ovarian cycle of the captive formosan gem‐faced civets (Paguma larvata taivana)

Formosan gem‐faced civets are classified to be endemic sub‐species of Paguma larvata in Taiwan. Little about their reproductive physiology has been reported. This study was designed to characterize the ovarian activity throughout the year and define ovarian cycle length and the lengths of its component phases. Serum samples were collected for enzyme immunoassay (progesterone and estradiol) from seven captive civets twice weekly for 1 year. Meanwhile, periodic changes in external genitalia (vulva swelling) and vaginal cytology were examined and recorded. Results showed estrous cycles exhibited two types: 18‐day (18.5±1.1, n=64) and 28‐day (27.6±1.0, n=28) as shown by progesterone and estradiol fluctuations and corresponding changes in vulva morphology and vaginal cytology. Both types showed a similar 7‐day follicular phase, peaking progesterone at Day 7. The 18‐day cycle type prevails in the spring and summer whereas the 28‐day cycle type is significant in the autumn. In summary, female gem‐faced civets are polyestrous (approximately 13 cycles/year), and non‐typical seasonal breeders, with follicular phase and two distinct durations of luteal phases (diestrus) cycling throughout the year, but the frequency of ovarian cycles was remarkably gradually decreased from September to February of next year. Zoo Biol 0:1–11, 2007. © 2007 Wiley‐Liss, Inc.     

Estrus induction in white rhinoceros (Ceratotherium simum)

The estrous cycle length in the white rhinoceros (Ceratotherium simum) is either 4 or 10 wk. The cause(s) for this variation as well as the poor fertility rate in captivity remains under debate in this species. Most captive adult white rhinoceros undergo long anovulatory periods without luteal activity which are considered a major reason for their low reproductive rate. In this study, the synthetic progestin chlormadinone acetate (CMA) was tested in combination with hCG or the GnRH analogue deslorelin for its efficiency to induce ovulation in fourteen females without luteal activity and in three, regular cycling females. HCG (N = 12), injectable GnRH analogue (N = 8) and GnRH analogue implants (N = 15) were given to induce ovulation after CMA treatment. Treatment success was determined using both transrectal ultrasonography and progesterone metabolite EIA analysis. A preovulatory sized follicle (3.5 ± 0.1 cm) or a corpus luteum (5.1 ± 0.7) was present on the ovary one day after induction in 93.1% of the treatments. Despite this high rate of ovarian response, ovulation rate differed between the study groups. The ovulation rate for hCG, injectable GnRH analogue and GnRH analogue implants was 66.7%, 62.5% and 93.3%, respectively. Ovulation rate in cyclic females treated with GnRH implants was 100% (6/6) compared with 89% (8/9) in females without luteal activity receiving the same treatment. The length of the estrous cycle when induced with hCG was 4 wk (85.7%). The estrous cycle when induced with GnRH analogue was predominantly 10 wk long. Two females without luteal activity treated with GnRH became pregnant. In conclusion, CMA in combination with GnRH analogue implants was highly effective to induce ovulation in white rhinoceroses and thus can contribute to efforts aimed at increasing natural mating and reproductive rates in the captive white rhinoceros population.     

Fecal progesterone and estrogen metabolite monitoring for cyclicity and pregnancy in southern tamandua (Tamandua tetradactyla)

Reproductive management of the southern tamandua (Tamandua tetradactyla) should include timed introductions for breeding to minimize aggression and pregnancy monitoring. Since serial blood sampling could cause unnecessary stress, and urinary progesterone metabolites are found in very low concentrations, this study sought to validate progesterone and estradiol enzyme immunoassays for measuring fecal progesterone metabolite (FPM) and fecal estrogen metabolite (FEM) concentrations in two females. Peaks in FEM concentrations coincided with breeding and conception, were 5–6 times higher than baseline concentrations, and were followed by clear luteal phases distinguished by FPM concentrations 5–6 times higher than baseline concentrations. FPM concentrations during the first 30–53 days of gestation overlapped with luteal phase concentrations, thereafter increasing to 8–25 times higher than baseline concentrations. FEM concentrations during the first 41–44 days of gestation remained near basal values for one female, whereas concentrations were 1.8 times higher than baseline for the second. FEM concentrations became elevated for the former by 44 days of gestation and increased further for the latter after 53 days, ultimately averaging four times higher than baseline for both females. The biphasic increase in FPM and FEM concentrations, follicular and luteal phase durations (follicular: 7 ± 1 days, luteal: 25 ± 1 days), total cycle length (41 ± 1 days), and gestation (161–165 days) documented in this study were consistent with previous reports from serum and urine analyses. Monitoring FPM and FEM is a reliable noninvasive method for tracking reproductive cycles and pregnancy in southern tamandua that overcomes the challenges associated with serum or urinary hormone analysis.     

Faecal steroid metabolites for non-invasive assessment of reproduction in common warthogs (Phacochoerus africanus), red river hogs (Potamochoerus porcus) and babirusa (Babyrousa babyrussa)

The objectives of this study were to analyse faecal steroid metabolites in African and South East Asian pig species kept in European zoos. Species studied were the warthog (Phacochoerus africanus), the red river hog (Potamochoerus porcus) and the babirusa (Babyrousa babyrussa). Faecal samples were collected 1-3 times per week from non-pregnant and pregnant captive female warthogs (n = 9), red river hogs (n = 7) and babirusas (n = 5). Enzyme-immunoassays for faecal progesterone, androgen, and oestrogen metabolites, were tested for their ability to determine follicular and luteal phases. In all three species, oestrous cycles could be monitored with 20alpha-OH- and 20-oxo-pregnane assays. In contrast, oestrogens and androgens were not useful in characterising follicular activity during the oestrous cycle in any species. Faecal 20alpha-OH- and 20-oxo-pregnane values were significantly correlated. Faecal pregnane concentrations revealed species-specific differences. Luteal phase values of 20alpha-OH-pregnanes were considerably higher than 20-oxo-pregnanes; 20alpha-OH-pregnanes were in the range of 3-10 microg/g in warthogs and red river hogs, whereas concentrations were 30-200 microg/g faeces in the babirusa. Regular oestrus cycles had a length of about 35 days in all three species studied. Results indicated a seasonal influence on the occurrence of reproductive cycles in the warthog with anoestrous periods in the European summer. The red river hog was found to be a seasonal and poly oestrous breeder; oestrus cycles started by January and continued until summer. In contrast, the babirusa showed non-seasonal ovarian cyclicity. In pregnant red river hogs, progesterone metabolites were comparable to luteal phase values of the oestrous cycle during the first 3 months of gestation, but did further increase during the last month of pregnancy. Oestrogens and 17-oxo-androstanes were significantly elevated during the second half of gestation. In summary, the reproductive biology of three exotic pig species was studied using non-invasive faecal steroid analysis and these methods were used for comparative investigations of oestrous cycles, pregnancy and seasonality.     

Reproductive characteristics of wild female Phayre's leaf monkeys

Understanding female reproductive characteristics is important for assessing fertility, interpreting female behavior, and designing appropriate conservation and captive management plans. In primate species lacking morphological signs of receptivity, such as most colobines, determination of reproductive parameters depends on the analysis of reproductive hormones. Here, we use fecal hormone analysis to characterize cycle patterns (N=6 females) and gestation length (N=7 females) in a group of wild Phayre's leaf monkeys (Trachypithecus phayrei crepusculus) in Phu Khieo Wildlife Sanctuary, Thailand. We found that both fecal estrogen (fE) and progestin (fP) levels showed clear biological patterns indicative of ovulation and conception. However, because fP patterns were inadequate in determining the end of the luteal phase, we used fE rather than fP patterns to delineate menstrual cycle parameters. We found a mean cycle length of 28.4 days (N=10), with follicular and luteal phases of 15.4 (N=10) and 12.5 days (N=14), respectively. On average, females underwent 3.57 (N=7) cycles until conception. Average gestation length was 205.3 days (N=7), with fE levels increasing over the course of pregnancy. Overall, the reproductive characteristics found for Phayre's leaf monkeys were consistent with results for other colobine species, suggesting that fecal hormone monitoring, particularly for fE metabolites, can provide useful reproductive information for this species. Am. J. Primatol. 72:1073–1081, 2010. © 2010 Wiley‐Liss, Inc.     

Differences in Fecal Androgen Patterns of Breeding and Nonbreeding Kori Bustards (Ardeotis kori)

To better understand breeding conditions to promote reproduction in captive kori bustards, fundamental endocrine studies measuring fecal androgen metabolites in male and female kori bustards were conducted. Feces collected weekly from males and females were analyzed for testosterone using enzyme‐linked immunoassay. Results from adult males (n = 5), adult females (n = 10), immature males (n = 10), and immature females (n = 10) revealed seasonally elevated testosterone concentrations in fertile, but not nonfertile adult males and females (P > 0.05). Adult females that were not maintained in a breeding group, or that did not produce eggs, did not demonstrate increases in testosterone compared to egg laying counterparts. In males, but not females, seasonal testosterone increases were accompanied by weight gain. Peaks in male fecal androgen metabolites ranged from 10‐ to 22‐fold higher than nonbreeding season (181.5 ± 19.1 vs. 17.0 ± 0.94 ng/g; P < 0.05). Mean breeding season values for adult males were 83.6 ± 6.1 ng/g vs. nonbreeding season values of 12.3 ± 0.73 ng/g (P < 0.05). In females, average breeding season testosterone concentrations were approximately 4‐fold higher than nonbreeding season (55.9 ± 6.0 vs. 14.5 ± 1.8 ng/g), with peaks 10‐ to 30‐fold higher. Results show that noninvasive fecal androgen metabolite analysis can provide a means of predicting fertility potential of male and female kori bustards and might be utilized to assess effects of modifying captive environments to promote reproduction in this species. Zoo Biol. 32:54‐62, 2013. © 2012 Wiley Periodicals, Inc.     

Endocrine profiles during the estrous cycle and pregnancy in the Baird's tapir (Tapirus bairdii)

Serum samples were collected 1–3 times weekly from two Baird's tapirs (Tapirus bairdii) for 6 months in 1987–1988, and for more than 3 consecutive years beginning in 1989 to characterize hormone patterns during the estrous cycle and pregnancy. Based on serum progesterone concentrations, mean (±SEM) duration of the estrous cycle (n = 20) was 30.8 ± 2.6 days (range, 25–38 days) with a luteal phase length of 18.1 ± 0.4 days (range, 15–20 days). Mean peak serum progesterone concentrations during the luteal phase were 1.35 ± 0.16 ng/ml, and nadir concentrations were 0.19 ± 0.03 ng/ml during the interluteal period. Distinct surges of estradiol preceded luteal phase progesterone increases in most (14/20) cycles. Gestation length was 392 ± 4 days for three complete pregnancies. Mean serum progesterone concentrations increased throughout gestation and were 1.83 ± 0.13, 2.73 ± 0.13, and 4.30 ± 0.16 ng/ml during early, mid- and late gestation, respectively. Serum estradiol concentrations began to rise during mid-gestation, increasing dramatically during the last week of pregnancy. Patterns of serum estriol and estrone secretion during pregnancy were similar to that observed for estradiol. In contrast to progesterone and estrogens, serum cortisol concentrations were unchanged during pregnancy or parturition. Females resumed cycling 16.2 ± 2.0 days after parturition (n = 4) and, on two occasions, females became pregnant during the first postpartum estrus. These data suggest that the tapir cycles at approximately monthly intervals and that increases in serum progesterone are indicative of luteal activity. The interluteal period is relatively long, comprising approximately 40% of the estrous cycle. During gestation, progesterone concentrations are increased above luteal phase levels, and there is evidence of increased estrogen production during late gestation. The absence of increased cortisol secretion at the end of gestation suggests that this steroid does not play a major role in initiating parturition in this species. © 1994 Wiley-Liss, Inc.     

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.     

Comparative analysis of gonadal and adrenal activity in the black and white rhinoceros in North America by noninvasive endocrine monitoring

Patterns of fecal reproductive steroid metabolites and adrenal corticoids were characterized for 12‐ to 24‐month periods in black (n = 10 male, 16 female) and white (n = 6 male, 13 female) rhinoceroses at 14 institutions. All black rhinoceros females exhibited at least some ovarian cyclicity on the basis of fecal progestogen analysis (range, 2–12 cycles/yr). However, cycles often were erratic, with many being shorter (<20 days; 18% of cycles) or longer (>32 days; 21%) than the average of 26.8 ± 0.5 days (n = 104 cycles). Five females exhibited periods of acyclicity of 2–10‐month duration that were unrelated to season. One complete and seven partial pregnancies were evaluated in the black rhinoceros. Fecal progestogens increased over luteal phase concentrations after 3 months of gestation. Females resumed cyclicity within 3 months postpartum, before calves were weaned (n = 5). Approximately half of white rhinoceros females (6 of 13) showed no evidence of ovarian cyclicity. Of the cycles observed, 5 were “short” (32.8 ± 1.2 days) and 24 were “long” (70.1 ± 1.6 days). Only two females cycled continuously throughout the study. One had both long (n = 9) and short (n = 2) cycles, whereas the other exhibited long cycles only (n = 5). Fecal estrogen excretion was variable, and profiles were not useful for characterizing follicular activity or diagnosing pregnancy in either species. Males of both species showed no evidence of seasonality on the basis of fecal androgen profiles. Androgen metabolite concentrations were higher (P < 0.05) in the black (27.6 ± 6.9 ng/g) than in the white (16.8 ± 3.1 ng/g) rhinoceros. An adrenocorticotropin hormone challenge in four black rhinoceros males demonstrated that the clearance rate of corticoid metabolites into feces was ～24 hours. Fecal corticoid concentrations did not differ between males and females, but overall means were higher in the black (41.8 ± 3.1 ng/g) than in the white (31.2 ± 1.7 ng/g) rhinoceros. In summary, fecal steroid analysis identified a number of differences in hormonal secretory dynamics between the black and white rhinoceros that may be related to differences in reproductive rates in captivity. Most black rhinoceros females exhibited some cyclic ovarian activity. In contrast, few white rhinoceroses demonstrated evidence of regular estrous cyclicity, and those females that were active had comparatively long cycles. Results also suggest that fecal corticoid concentrations reflect adrenal activity and may be species specific. Continued studies are needed to determine whether fecal corticoid measurements will be useful for understanding the cause of inconsistent gonadal activity in these two species. Because all but three (15.8%) of the white rhinoceroses evaluated in this study were less than 20 years of age compared to 73.1% (19 of 26) of the black rhinoceroses, the impact of age on reproductive and adrenal activity also needs to be evaluated further. Zoo Biol 20:463–486, 2001. © 2002 Wiley‐Liss, Inc.     

Body weight as an effective tool for determination of onset of puberty in captive female Nile hippopotami (Hippopotamus amphibious)

Profiles of fecal progestogens and body weight from the early juvenile to the peri‐pubertal period are presented for eight captive female Nile hippopotami housed at Disney's Animal Kingdom in Florida. Average growth rate in juveniles was 0.85±0.03 kg/day (r²=0.913). Progestogen elevations were detectable as early as 16.8 months of age, and elevations indicative of ovulation and luteal activity were identified in seven of eight females by 30.3±1.6 months of age and body weight of 829.3±49.4 kg. Progestogen patterns before the onset of puberty were highly variable within and between females. Some females remained at baseline concentrations, whereas in others the progestogen pattern was characterized by infrequent, transient elevations of low amplitude and shortened duration. Four females were monitored through onset of puberty, conception, and first pregnancy. Onset of puberty was defined as the first luteal phase from the series of consecutive ovarian cycles culminating in conception and was observed at 34.9±2.2 months of age and 963.6±39.4 kg, however, the quality and number of cycles varied among females before conception. Females conceived between 2.7–3.9 years of age after attaining an approximate threshold body weight of 1,000 kg (1,070.5±39.5 kg). The age at first conception in captivity occurs at a younger age than has been reported for wild populations. Body weight may be an effective tool for approximating the state of reproductive maturity and facilitate collection management in zoos. Zoo Biol. 0:1–13, 2005. © 2005 Wiley‐Liss, Inc.     

Suppression of ovulation in Nile Hippopotamus (Hippopotamus amphibious) using melengestrol acetate‐treated feed or high dose Depo‐Provera injection

Analysis of fecal progestogen profiles during Depo‐Provera injection (1,200 mg; DEPO, Pfizer Inc., New York, NY), melengestrol acetate (MGA) in feed (2 or 3 mg/head/day), and a combination treatment (DEPO+MGA) are presented for nine captive female Nile hippos housed at Disney's Animal Kingdom in Florida. All tested treatments reduced fecal progestogen elevations successfully to durations consistent with prevention of ovulation for a portion of the treatment period. Percentage of treatment months with suppression of luteal phases indicative of ovulation was maximal for high‐dose MGA (91.7±13.9%) and DEPO+MGA (91.7±20.4%), followed by DEPO injection alone (69.2±13.9%) and low‐dose MGA (57.6±33.2%). Both 1,200 mg DEPO and low‐dose MGA (2.0 mg/day) treatments were insufficient to prevent an apparent seasonal breakthrough of ovarian activity from June–August 2002. Although luteal phases were observed, no females conceived during those months. Overall, in 133.5 treatment months with females housed with an adult male, one female conceived during the transition period between treatments. After cessation of contraceptive treatment, average latency to first normal ovarian cycle was 80.6±19.5 days (range = 22–179 days). Up to 12 months post‐treatment, however, successive cycles were often irregular with evidence of short periods of anovulation and shortened luteal phases in all females monitored. In conclusion, high dose and combination treatments were most successful in preventing progestogen increases indicative of ovulation in hippos. Zoo Biol 26:259–274, 2007. © 2007 Wiley‐Liss, Inc.     

Reproductive biology and management of captive black-footed ferrets (Mustela nigripes)

A captive breeding program is being conducted with black-footed ferrets (Mustela nigripes), an endangered species. Results of 5 years of study are reported. Simple, but specialized, nontraumatic handling techniques allowed assessment of reproductive status with minimal stress, which was important in breeding management. Black-footed ferrets are sexually mature and may successfully reproduce in their 1st year. Proestrus lasts approximately 2-3 weeks. Duration of estrus in unbred females was 32–42 days; females usually bred within 20 days. Most breeding activity occurred during April. Mean gestation length was 42.7 days (±0.7, range 42–45 days), litter size averaged 3.0 kits (±1.4, range 1–6 kits), and weaned kits/litter averaged 2.4 (±1.7, range 1–6 kits). Weaning rate of kits was 80%. Sex ratio of kits was essentially 1:1. Productivity was greatest among females ?3 years of age. Rapid expansion of the captive population is possible and will be important for genetic management of the species and for achieving the primary goal of the recovery program, which is to return black-footed ferrets to the wild.     

Reproductive endocrine patterns in captive female and male red wolves (Canis rufus) assessed by fecal and serum hormone analysis

Reproductive steroid profiles in female (n=13) and male (n=5) red wolves (Canis rufus) were characterized in fecal samples collected during the breeding season (December—May) and over a 1 year period, respectively. Blood samples from females (n=12) also were collected during the periovulatory period for luteinizing hormone (LH) and steroid analysis. High performance liquid chromatography (HPLC) of fecal extracts determined that estradiol and estrone constituted the major and minor forms, respectively, of fecal estrogen metabolites. Although native progesterone was present, pregnane metabolites predominated as the major forms of fecal progestins. HPLC analysis of fecal extracts from males revealed no native testosterone, but rather the predominance of more polar androgen metabolites. Based on hormone profiles and/or pup production, females were classified as pregnant (n=3), ovulatory‐nonpregnant (n=9), or acyclic (n=3). Longitudinal monitoring of females indicated no pregnancy‐specific differences in concentrations of either fecal progestagen or estrogen metabolites compared to ovulatory‐nonpregnant individuals; however, baseline progestagen concentrations were consistently elevated in acyclic females. There was good correspondence between serum and fecal steroid concentration during the periovulatory period. A rise in serum estrogens preceded the ovulatory LH surge which was then followed by a significant progesterone rise during the luteal phase. In males, changes in fecal androgen metabolite concentrations coincided with photoperiod fluctuations, increasing in late autumn and reaching peak concentrations during mid‐ to late winter just before the start of the breeding season. Collectively, these results serve as a database of ovarian and testicular endocrine events in this species, which can be utilized in population management and application of assisted reproductive technologies. Zoo Biol 21:321–335, 2002. © 2002 Wiley‐Liss, Inc.     

Effect of season on hormonal profile and some biochemical parameters at different stages of estrous cycles in Baladi goats

Understanding the seasonal patterns of estrus cycle in caprine is crucial to develop the efficient breeding plans in the subtropics. Thus, the aim of the current research was to evaluate the effects of breeding season on hormonal profile and blood biochemical indices at different stages of estrus cycle in normal breeding or out-of-season breeding in goats. Forty-four Baladi goats were monitored for a period of eight months (July–February). Baladi goats exhibit a normal seasonal breeding (NS) at midsummer and continue through the autumn season (68%), with a considerable percentage of females having estrus signs during out-of-season (OS) period (32%). At the mid and late luteal phases of estrus cycles, the NS breeding group had significantly higher serum progesterone level than that reported in the OS group (p = 0.013 and 0.039, respectively). At the estrus and late luteal phases of estrus cycles, the NS breeding group had significantly higher serum β-estradiol level than that reported in the OS group (p = 0.022 and 0.001, respectively). Compared to the OS group, the NS breeding group had significantly higher serum cholesterol at the mid and late luteal phases of estrus cycle (p = 0.001 and 0.016, respectively), and higher serum glucose level in the early luteal phase of the cycle (p = 0.009). In conclusion, the NS breeding goats had superior progesterone (mid-luteal and late luteal phases) and estradiol (estrus and late luteal phases) profiles than that reported in the OS group. This may indicate specific approaches to maintain the breeding efficiency of goats during the out-of-season period.     

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.     

Ovarian function in the elephant: luteinizing hormone and progesterone cycles in African and Asian elephants

Serum samples were collected weekly for 3 yr from two female African elephants, for 18 mo from two other female African elephants, and for 2 yr from two female Asian elephants. Animals were not sedated at the time of blood collection. Ovarian cycles, characterized by changes in progesterone and immunoreactive luteinizing hormone (ILH) concentrations, averaged 15.9 +/- 0.6 wk (N = 25) for African females and 14.7 +/- 0.5 wk for Asian females (N = 10). The length of the active luteal phase averaged 10.0 +/- 0.3 wk for African elephants (range 8-14 wk) and 10.6 +/- 0.6 wk for Asian females (range 9-13 wk). Interluteal phases were 5.9 +/- 0.6 wk for African females and 4.2 +/- 0.5 wk for Asian females. One African female (Maliaca) had two extended interluteal phases, both occurring between the months of February and May. Excluding these two periods, there were no differences in the length of the ovarian cycle or the length of the luteal phase between species of elephant. Serum progesterone in both species ranged from less than 50 pg/ml to 933 pg/ml. Average progesterone concentrations during the luteal phase were significantly lower in African elephants compared with Asian elephants (328 +/- 13, N = 30 cycles vs. 456 +/- 23, N = 14 cycles; p less than 0.001). ILH ranged from nondetectable to 11.6 ng/ml. These data suggest that the length of the ovarian cycle in the African elephant is about 16 wk and confirm that the length of the ovarian cycle in the Asian elephant is about 15 wk.     

Reproductive steroid hormones and ovarian activity in felids of the Leopardus genus

Reproductive endocrine patterns were characterized in female ocelots (Leopardus pardalis; n = 3), tigrinas (Leopardus tigrinus; n = 2), and margays (Leopardus wiedii; n = 2) housed in captivity in southern Brazil. Females were maintained as singletons and exposed to natural fluctuations in photoperiod. Cyclic changes in ovarian steroids were monitored by analyzing estrogen and progestogen metabolites in fecal samples collected five times weekly for 14 to 18 months. Based on intervals between fecal estrogen peaks, mean (± SEM) duration of the estrous cycle was 18.4 ± 1.6 days for the ocelots (range, 7–31 days; n = 75 cycles), 16.7 ± 1.3 days for the tigrinas (range, 11–27 days; n = 23 cycles), and 17.6 ± 1.5 days for the margays (range, 11–25 days; n = 32 cycles). Fecal progestogen analyses combined with two laparoscopic observations of the ovaries confirmed that ocelots and tigrinas did not ovulate spontaneously. In contrast, non‐mating–induced luteal phases of 40.1 ± 6.3 days in duration (range, 30–60 days) were observed frequently in both margays. There was no evidence of gonadal seasonality in margays in either follicular or luteal activity. In ocelots, cyclic changes in estrogen excretion were observed during each month of the year; however, only one female cycled continuously. In the other two ocelots, periods of acyclicity of several months’ duration were observed. It was not possible to conclude whether tigrinas were aseasonal because estrous cyclicity was observed in only one of two individuals. In the female that cycled, a 3‐month period of acyclicity was observed in the late fall/early winter. These data demonstrate similarities among three felid species of the genus Leopardus, including evidence they are polyestrous but experience unexplained periods of ovarian inactivity. Only the margays differed by exhibiting occasional spontaneous, non‐mating–induced ovulations. Historically, these species have not bred well in captivity. However, it is hoped that understanding the biological similarities and differences among them could lead to improved management strategies that may one day result in increased reproductive success. Zoo Biol 20:103–116, 2001. © 2001 Wiley‐Liss, Inc.