Fecal Progesterone Concentrations Research Articles

Validation and effects of drying and prey hair on fecal hormone concentrations in spotted hyenas

Abstract As fecal steroid methods increasingly are used by researchers to monitor the physiology of captive and wild populations, we need to expand our validation protocols to test the effects of procedural variation and to identify contamination by exogenous sources of steroid hormones. Mammalian carnivore feces often contain large amounts of hair from the prey they consume, which itself may contain high concentrations of hormones. In this study, we report first a validation of two steroid hormone antibodies, corticosterone and progesterone, to determine fecal concentrations of these hormones in wild spotted hyenas (Crocuta crocuta). Next, we expand on these standard validation protocols to test two additional metrics: (i) whether hair from consumed prey or (ii) the specific drying method (oven incubation vs. lyophilization) affect steroid hormone concentrations in feces. In the first biological validation for the progesterone antibody in this species, progesterone concentrations met our expectations: (i) concentrations of plasma and fecal progesterone were lowest in immature females, higher in lactating females, and highest in pregnant females; (ii) across pregnant females, fecal progesterone concentrations were highest during late pregnancy; and (iii) among lactating females, fecal progesterone concentrations were highest after parturition. Our additional validation experiments indicated that contamination with prey hair and drying method are hormone-specific. Although prey hair did not release hormones into samples during storage or extraction for either hormone, its presence appeared to “dilute” progesterone (but not corticosterone) measures indirectly by increasing the dry weight of samples. In addition, fecal progesterone, but not corticosterone, values were lower for lyophilized than for incubated samples. Therefore, in addition to the standard analytical and biological validation steps, additional methodological variables need to be tested whenever we measure fecal hormone concentrations, particularly from predatory mammals.

MONITORING OF REPRODUCTION AND INFLUENCE OF FECAL PROGESTERONE ON REPRODUCTIVE CYCLICITY IN CAPTIVE SRI LANKAN SAMBAR DEER (RUSA UNICOLOR UNICOLOR)

This study examines the length of the estrous cycle in 16 Sambar deer hinds in National zoological gardens in Dehiwala and Kegalle, Sri Lanka (NZGDK) assessed with the use of changes in progesterone concentrations, along with the changes in the profile of this hormone and by the visual estrus manifestations. The objectives of the present study were to characterize ovarian activity throughout the estrous cycle and the non-pregnant luteal phase of captive sambar deer in Sri Lanka. These objectives were achieved with the use of radioimmunoassay (RIA) to measure fecal concentrations of progesterone and visual estrus manifestation. Fecal samples were collected from non-pregnant sambar deer hinds (aged 2–4 years)over the period of six months on daily basis, both during breeding and non-breeding seasons. Estrous cycles were recorded in non-pregnant females, based on fecal progesterone concentrations. The average estrous cycle length was 26.1±2.08 days (mean ± SEM) and 2.10 ± 0.51 days in the inter-luteal phase.The average fecal progesterone concentrations attained the peak mid-luteal values of 2.74 ng mL–1. There appeared to be variation in fecal progesterone amplitude between animals and between dates, but the low frequency of sampling prohibited confirmation of trends. Behavioral estrus was detected only when the average progesterone concentrations were less than 0.07 ng mL–1. However, not all periods of depressed progesterone secretion were associated with the observed estrus. Behavioral estrus was detected in hinds when progesterone concentrations were less than 0.07 ng mL–1; a subsequent rise in progesterone indicated ovulation taking place at this time.

Fecal Cortisol and Progesterone Concentrations in Post Partus of Etawah Crossbreed Goat

Progesterone (P4) is a dominant hormone during pregnancy. In the later stage of pregnancy, the stress hormone particularly cortisol (C) may increase for initiating the parturition process as a consequence of fetal stress. This study was a preliminary study to compare the concentration of P4 and C in feces of Etawah Crossbreed Goat during their last stage of pregnancy and post partus. This study used 5 pregnant Etawah Crossbreed Goats (t 20th weeks) of pregnancy. Fecal samples were collected in the 20th week of pregnancy to 2 weeks of postpartum. All fecal samples were then dried using a freeze dryer (Labfreez FD10-MR) for 7 days at -80°C. Afterward, dried feces were pulverized and extracted by using 3ml of methanol 80%. The fecal extract was then analyzed the P4 and C concentrations using the enzyme-linked immunosorbent assay method. Concentrations of P4 and C metabolites in the last stage of pregnancy were 5,506.18 3,396.72 ng/g dry feces and 136,625.83 42,479.22 ng/g feces, respectively. Concentrations of P4 and C metabolites in the 2 weeks postpartum decreased at 669.38 P 643.9 ng/g feces and 110,295 / 14,378, 8 ng/g feces, respectively. It canbe concluded that there was a difference in the fecal progesterone and cortisol concentrations between the last phase of pregnancy and the postpartum phase.

SUCCESSFUL LAPAROSCOPIC OVIDUCTAL ARTIFICIAL INSEMINATION IN THE CLOUDED LEOPARD (NEOFELIS NEBULOSA) IN THAILAND.

Captive breeding of clouded leopards (Neofelis nebulosa) is challenging because of mating incompatibility, high incidence of teratospermia in males, and inconsistent ovulation patterns in females. Assisted reproductive techniques, therefore, are necessary to overcome these issues and maintain the genetic diversity in the captive population. The objective was to use laparoscopic oviductal artificial insemination (AI) to breed genetically valuable females (n = 4; aged 4.5-5 yr) that were unsuccessfully paired. Fecal hormone metabolites (estrogen and progesterone) were extracted and measured by enzyme immunoassay for monitoring of ovarian activity 45 days before and 65 days after laparoscopic AI. For timed insemination, females were injected with 200 IU equine chorionic gonadotropin and 1,000 IU porcine luteinizing hormone (pLH) at the 82-hr interval. Ovarian assessment was performed by laparoscopy 44 hr after pLH administration. One nulliparous female out of four presented two ovulation sites on each ovary. The single female that had ovulated was inseminated with chilled semen collected from two males (8 × 106 and 2.7 × 106 motile spermatozoa, respectively, in each oviduct). A significant increase in fecal progesterone concentrations was observed after AI with a concentration peak (500 μg/g dry feces) detected on day 24 after pLH injection, which was then sustained for more than 45 days after the pLH injection. The delivery of two cubs occurred on day 92 after pLH. Microsatellite marker analysis determined that both cubs were sired by the same male. This is the first report of a successful oviductal AI in the clouded leopard.

Determination of ovarian cyclicity and pregnancy using fecal progesterone in forest musk deer (Moschus berezovskii)

The forest musk deer (FMD, Moschus berezovskii) is a threatened species in China. Although crucial for its artificial breeding management and thus protection, to date, gonadal steroidogenic activity data are unavailable in this species. Thus, the objectives of the present study were to characterize ovarian activity throughout the estrous cycle, non-pregnant luteal phase, and gestation in female FMD. These goals were accomplished using an enzyme immunoassay to measure fecal concentrations of estradiol (E2) and progesterone. Fecal samples were collected from female FMD (aged 3–4 years) for one year, including during breeding and non-breeding seasons. Non-pregnant estrous cycles were recorded in females, based on fecal progesterone concentrations, their overall estrous cycle length was (mean±SEM) 24.3±0.5 days, with 21.6±0.5 days in the luteal phase and 2.7±0.3 days in the inter-luteal phase. Fecal progesterone and E2 concentrations were also measured in females that became pregnant and gave birth after gestating approximately 6 months. Two weeks after becoming pregnant, the average fecal progesterone concentration was significantly greater than that during non-pregnancy. The average fecal progesterone concentrations during pregnancy increased 3.2-fold above non-pregnant concentrations, decreasing to non-pregnant concentrations only after parturition. By contrast, average fecal E2 concentrations during gestation and after parturition were not different from average non-pregnant concentration. In addition, no difference was observed between progesterone concentration in the first month after pregnancy and the value during the luteal phase. However, progesterone concentration during the second month of pregnancy was significantly higher than the value during the luteal phase. In conclusion, monitoring fecal progesterone is an effective method for assessing ovarian function in FMD and will be a useful tool for breeding management and development of assisted reproductive techniques, such as artificial insemination, in this species.

Reproductive hormone monitoring of dugongs in captivity: Detecting the onset of sexual maturity in a cryptic marine mammal

Determining the reproductive status of long-term captive animals is essential because the onset of sexual maturity and reproductive activity may necessitate changes in husbandry requirements. This study reports on the first multi-year reproductive hormone monitoring program for captive dugongs of both sexes using feces. Fecal samples were collected from one male (Pig) over 9 years (4–13.2y of age; n=288 samples, 0.8±0.1 samples per week from July 2007 to February 2012) and one female (Wuru) over 7 years (from neonate to 6.9 y; n=171 samples, 0.5±0.1 samples per week from July 2007 to February 2012), and from one solitary female dugong (Gracie) over 10 months (10.5–11.3y of age; n=54 samples, 1.1±0.2 sample per week from September 2008 to June 2009). Using enzyme-immunoassay, fecal progesterone (fP) and estradiol-17β (fE) concentrations were assayed in the two captive females, and testosterone (fT) concentration in the captive male, and compared these to concentrations in wild dugongs. Female Wuru exhibited increasing fP concentrations at 5+ y, indicating early onset of ovarian cycling typical of non-pregnant adult females. Female Gracie maintained basal fP concentrations consistent with wild immature dugongs, indicating that she had not reached puberty by 11y. Nutritional plane may account for differences in age at sexual maturity in these female dugongs. At age 3–4y, Wuru had fE concentrations 1.4 times greater than maximum concentrations recorded in all wild females, and these concentrations were coincident with a period of rapid weight gain. For the male Pig, increasing fT concentrations at 9y provided early indications of puberty. Pig's tusks erupted by 11y, and sexual maturity (indicated by spermatic semen) was confirmed by 12.8y. Identification of sexual maturation prompted two trials of a male contraceptive treatment using the GnRH agonist, deslorelin (9.4mg administered in 2010 and 15.6mg in 2011). Testosterone production was not significantly suppressed by these dosages, and treatment did not terminate sperm production at week 10–11 post-implantation, even at the larger dose tested. Routine analysis of fecal hormones was helpful for making reproductive management decisions regarding individual captives and in guiding the long-term captive management of this cryptic species.

Effects of storage temperature and time on fecal progesterone concentration<br>in camel (Camelus dromedarius)

This study aimed to evaluate the effect of temperature (-20°C, + 4°C, room temperature) and storage time (7, 15, 107 and 173 days) of feces on progesterone concentration in camel (Camelus dromedarius). Plasma and feces were collected from 10 pregnant and one non-pregnant camels. Extraction of fecal metabolites of progesterone was performed with methanol and petroleum ether. The analytical validation was provided by internal quality control (IQC) and the success of the validation tests (sensitivity, precision, recovery and parallelism). In comparison to the value found in the day of collection, the mean concentration of progesterone in feces which was frozen or dried at room temperature showed no significant difference after 7 and 15 days. A significant increase was found for fecal samples stored at + 4°C. After 107 and 173 days, freezing is inadequate condition of storage because the fecal progestagen concentrations vary significantly. However, drying feces at ambient temperature maintained stable progestagen concentrations. Therefore, results indicated that drying feces is a reliable method, independent from an electric power source and the freezing equipment.

Fecal progesterone analysis for monitoring reproductive status in dairy goats

The present study was undertaken to evaluate the use of fecal progesterone (FP_4) concentration for early pregnancy diagnosis, estrus detection, and predicting the litter size and parturition date in dairy goats. Fecal samples were collected from 17 hand-mated goats 3 times a week for 22-23 weeks, beginning on the day of mating. The levels of FP_4 were determined by enzyme-linked immunosorbent assay (ELISA). Significant positive correlations were found between the levels of serum P_4 and FP_4 (r = 0.8787, n = 13). Pregnancy diagnosis was performed at 2 months postmating with transabdominal ultrasonography and confirmed upon birth of the offspring. The results indicated a significant difference in the mean FP_4 concentration obtained during days 19 and 20 postmating between the pregnant and nonpregnant does (2492.4 ± 239.1 vs. 577.0 ± 112.9 ng/g, P < 0.05). A significant drop in the FP_4 concentration was noted 3 days prior to the detected day of estrus (P < 0.05). The mean weekly FP_4 profile obtained in this study showed a progressive increase from week 7 to 14 until a plateau was reached between weeks 15 and 21, and then a rapid decline began 5 to 6 days prepartum, with a significant drop 1-2 days prepartum (from 3884.3 ± 576.0 to 1205.0 ± 339.0 ng/g, P < 0.05). No significant correlation was observed between the FP_4 concentration and the number of kids born. In conclusion, the measurement of FP_4 concentration could potentially be an alternative method for early pregnancy diagnosis, prediction of estrus, and parturition in dairy goats.

A survey of the effects of wolf predation risk on pregnancy rates and calf recruitment in elk

We have previously found that the behavioral responses of elk to the risk of predation by wolves are correlated with changes in habitat selection, altered diets, reduced food intake, decreased fecal progesterone concentrations, and decreased calf recruitment. P. J. White et al. recently questioned these results, concluding that “multiple lines of evidence and/or strong validation should be brought to bear before relying on indirect measures of how predators affect pregnancy rates.” Here, we systematically surveyed available data and found that five studies (with data from 10 widely distributed populations) have directly detected decreases of 24–43% in elk pregnancy rates in response to increased predation risk. This survey includes data not discussed by White et al. from their own research, which reveal a 32% decrease in pregnancy rates following wolf recolonization in central Yellowstone. Following the survey of available data, we discuss several methodological and statistical problems in White et al.'s study that would be expected to mask the effects of predation risk. While other factors also clearly affect elk recruitment, multiple lines of evidence using a broad array of methods have detected an association between predation risk and reduced reproduction in elk.

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.

Seasonal changes in ovarian steroid hormone concentrations in the large hairy armadillo (Chaetophractus villosus) and the crying armadillo (Chaetophractus vellerosus)

Knowledge of armadillo reproductive physiology is essential for developing ex situ and in situ assisted reproductive techniques for propagating and/or controlling populations of these animals. The present study included assessment of fecal sex steroids by radioimmunoassay, determining reproductive status via monitoring ovarian activity (in the wild) and therefore reproductive status, in wild females of the large hairy armadillo (Chaetophractus villosus) and the crying armadillo (Chaetophractus vellerosus) in the southern hemisphere. Plasma and fresh fecal progesterone concentrations were not significantly correlated in either species. However, in both species, there was a significant positive correlation between plasma progesterone and dry fecal progesterone concentrations (r = 0.82, P < 0.05 and r = 0.60, P < 0.05, respectively). Dry fecal progesterone and estradiol concentrations were measured in one captive C. villosus (average baseline progesterone and estradiol concentrations 28.72 ± 11.75 ng/g dry feces and 3.04 ± 0.80 ng/g dry feces, respectively) and one captive C. vellerosus (average baseline progesterone and estradiol concentrations 14.05 ± 3.03 ng/g dry feces and 3.46 ± 1.20 ng/g dry feces, respectively) to detect hormonal peaks over 1 y; these occurred from late fall to early summer. Feces from wild C. villosus and C. vellerosus were also collected over 1 y to determine progesterone peaks, which occurred in winter and spring in both species (with no peaks during the summer or fall). Accordingly, C. villosus and C. vellerosus had a seasonal reproductive pattern. The significant correlations between dry fecal and plasma progesterone concentrations validated this method for monitoring reproductive status in these species.

Body condition and pregnancy in northern Yellowstone elk: Evidence for predation risk effects?

S. Creel et al. reported a negative correlation between fecal progesterone concentrations and elk:wolf ratios in greater Yellowstone elk (Cervus elaphus) herds and interpreted this correlation as evidence that pregnancy rates of elk decreased substantially in the presence of wolves (Canis lupus). Apparently, the hypothesized mechanism is that decreased forage intake reduces body condition and either results in elk failing to conceive during the autumn rut or elk losing the fetus during winter. We tested this hypothesis by comparing age-specific body condition (percentage ingesta-free body fat) and pregnancy rates for northern Yellowstone elk, one of the herds sampled by Creel et al., before (1962-1968) and after (2000-2006) wolf restoration using indices developed and calibrated for Rocky Mountain elk. Mean age-adjusted percentage body fat of female elk was similarly high in both periods (9.0%-0.9% pre-wolf; 8.9%-0.8% post-wolf). Estimated pregnancy rates (proportion of females that were pregnant) were 0.91 pre-wolf and 0.87 post-wolf for 4-9 year-old elk (95% CI on difference = -0.15 to 0.03, P = 0.46) and 0.64 pre-wolf and 0.78 post-wolf for elk > 9 years old (95% CI on difference = -0.01 to 0.27, P = 0.06). Thus, there was little evidence in these data to support strong effects of wolf presence on elk pregnancy. We caution that multiple lines of evidence and/or strong validation should be brought to bear before relying on indirect measures of how predators affect pregnancy rates.

Fecal progesterone and estradiol changes during the breeding season in captive female wolf

Understanding basic reproductive physiology is crucial for the management of both captive and free-ranging wolf. In the present study, we determined hormonal changes during pregnancy and the estrous cycle in captive female wolf by measuring fecal steroids collected during the breeding season with high performance liquid chromatography (HPLC). These biochemical analyses were validated using chemical devivatization and mass spectrometry, and interpreted along with the behavioral data. All four females undergoing estrus cycles were copulated with their partners and delivered pups successfully. We found that estradiol concentrations were significantly higher during the estrus cycle than other stages (p<0.01) and progesterone was also significantly increased throughout the pregnancy (p<0.01). These hormonal fluctuations demonstrated pregnancy-specific changes in the fecal progesterone and estradiol concentrations. Patterns of fecal estradiol and progesterone concentrations during estrous cycles were similar to those reported for other canids.

Plasma and Fecal Sex Steroid Hormone Profiles During the Estrous Cycle in a Japanese Serow (Capricornis crispus)

We aimed to determine plasma progesterone and estradiol-17beta concentrations, as well as fecal progesterone concentrations during the estrous cycle in a female 8-year-old Japanese serow (Capricornis crispus). The step frequencies during the night were recorded by a pedometer attached to the serow's hind leg from October to the following June. Estrous behavior was also monitored during the day. Blood samples were taken once a day from 8 February to 10 March from an indwelling catheter placed in the jugular vein. Fecal samples were taken once or twice a day from 1 January to 29 April. Plasma and fecal progesterone and plasma estradiol concentrations were determined using time-resolved fluoroimmunoassays. The estrus behavior observed lasted for 2-3 days. Peak step frequencies were recorded between November and April, at intervals of 17-19 days. Plasma progesterone concentrations remained elevated (1-7.7 ng/ml) for 12 days during non-estrus, and plasma estradiol concentrations were highest when the peak step frequency and estrous behavior were observed. Step frequency increased around the times fecal progesterone levels fell to basal levels. Progesterone concentrations in feces were significantly correlated with those in sera. Thus, measurement of fecal progesterone concentrations might be useful for monitoring the reproductive status of the Japanese serow.

Noninvasive Measurement of Fecal Progesterone Concentration in Toy Poodles by Time Resolved Fluoroimmunoassay (TR-FIA)

Progesterone is an important reproductive hormone and measurement of its level by repeated blood samplings is beneficial to monitoring of estrus cycle. However, since toy poodles have a small body size and thin-walled blood vessels, repeated blood samplings cause stress and affect their preparation for mating or artificial insemination (AI). Therefore, a noninvasive method for monitoring progesterone concentration should be developed. Here, we show that time-resolved fluoroimmunoassay (TF-RIA) is a useful noninvasive method for determining the progesterone concentration in serum and fecal samples obtained from toy poodles. Present results demonstrate that progesterone concentrations in the fecal correlated with the serum collected in same time and the sequential changes in progesterone concentrations in the feces are paralleled in the serum. Therefore, this technique may be suitable for monitoring the estrus cycle in toy poodles.

Changes in Fecal Progestagen Profile After Excretion in Miniature Pigs

The aim of this study was to evaluate whether the fecal progestagen (progesterone and its metabolites) levels of miniature pigs would change after excretion at room temperature. Our initial investigation focused on the correlations between the fecal progestagen concentrations with and without ether extraction and between the plasma progesterone and fecal progestagen concentrations in order to develop an enzyme-linked immunosorbent assay (ELISA) for fecal progestagen without ether extraction. There were significant correlations between fecal progestagen concentrations with and without ether extraction (r=0.880) and between fecal progestagen concentrations without ether extraction and plasma progesterone (r=0.763). The fecal progestagen concentration obtained by ELISA without ether extraction was almost identical to that obtained with ether extraction. These results validate the ELISA method without ether extraction, which was therefore used for the latter experiment. Fecal samples collected from the pigs were preserved for 0-24 h at room temperature, and then their fecal progestagen concentrations were measured. The fecal samples preserved for 0 to 24 h were analyzed by high performance liquid chromatography (HPLC) and ELISA. The concentrations of all samples significantly increased with time after preservation. The progestagen concentration of fresh feces (0 h) with high progestagen concentration (>1000 ng/g) increased significantly after 3 h. The concentration increased significantly after 12 h for fresh feces containing about 500 ng/g progestagen. HPLC analysis is showed that the fecal progesterone concentration, but not its other metabolites, doubled 24 h after excretion compared with the concentration at 0 h. These results suggest that dynamic changes in the profile of progesterone metabolites occur in feces after excretion.

Pregnancy diagnosis based on the fecal progesterone concentration in beef and dairy heifers and beef cows

The present study was undertaken to examine whether pregnancy diagnosis was possible by measuring fecal progesterone concentrations in beef and dairy heifers and beef cows. Rectal fecal samples collected on days 18–24 after insemination or days 11–17 after embryo transfer were mixed with methanol and shaken for preparation of a fecal solution. After centrifugation, the supernatant was extracted with petroleum ether followed by an enzyme immunoassay for progesterone. All pregnant animals showed fecal progesterone concentrations greater than 50 ng/g of fecal material on days 18–24 after AI or estrus. In non-pregnant animals, however, the fecal progesterone concentrations ranged widely from 5 to 180 ng/g of fecal material. In non-pregnant cattle, the percentage of cattle with <50 ng progesterone/g of fecal material compared with the total number was 37–60% on days 18–20, whereas the percentages increased more than 70% to a maximum of 78.1% on day 23. When 50 ng/g was considered as the cut-off value, the sensitivity and specificity of positive pregnancy tests were less than 70% on days 21–24, and 100% for negative pregnancy tests on days 18–24. There were significant differences in the mean fecal progesterone concentrations between pregnant and non-pregnant cattle on days 19–24. These results suggest that feces can be utilized to substitute for plasma and milk to measure progesterone for the purpose of pregnancy diagnosis in heifers and cows.

Enzyme immunoassay of progesterone in the feces from beef cattle to monitor the ovarian cycle

The present study was undertaken to measure fecal progesterone concentration of beef cattle using antibody against authentic progesterone and to examine whether this method can monitor the ovarian cycle in beef cattle. Rectal fecal samples collected from 14 beef cattle were mixed with 6 ml of 100% methanol and shaken for 15 min. After centrifugation, supernatant was extracted with petroleum ether followed by an enzyme immunoassay (EIA) for progesterone. Specificity of the assay was examined by HPLC separation of fecal solution followed by the EIA in each fraction. The present assay identified only progesterone but not other metabolites in the feces sample that was extracted with petroleum ether. Sensitivity of the assay was estimated to be 0.0055 ng/ml (0.11 ng/g). Coefficient variations of intra- and inter-assay were 9.6–10.9% and 10.8–16.6%, respectively. Recovery rates ranged between 73 and 84%. Patterns in the fecal progesterone concentrations during the ovarian cycle were almost parallel to the plasma concentrations. A significant positive correlation was established between the fecal and plasma progesterone concentrations in individual animal ( r = 0.59–0.84, P < 0.001, n = 10) as well as pooled data ( r = 0.70, P < 0.001, n = 65). Fecal progesterone concentrations of day 0 (showing the nadir of concentration) of the ovarian cycle were less than 50 ng/g, which increased significantly toward day 9 ( P < 0.01). From days 14 to 18, there was significant reduction of fecal progesterone concentration ( P < 0.01). Ovarian cycles had at least 48 ng/g (mean = 74 ng/g) of difference between minimum and maximum fecal progesterone concentrations. All cattle at days 9, 11 and 14 had higher fecal progesterone concentrations by more than 20 ng/g compared with day 0. These results suggest that the present EIA is suitable to measure the progesterone in cattle feces and can monitor ovarian cycle.

Changes in sexual behavior and fecal steroid hormone concentrations during the breeding season in female Hokkaido brown bears (Ursus arctos yesoensis) under captive condition.

The longitudinal changes in fecal steroid hormone concentrations and sexual behavior in 2 mated/pregnant and 3 non-mated female Hokkaido brown bears were investigated during the breeding season. Behavioral estrus (standing) lasted for 14 and 32 days in the mated females and for 25 to 36 days in the non-mated females. In non-mated females, sexual behavior, such as female-female mounting and masturbation, was observed for several days before and after the estrous period. In mated females, mean fecal estradiol-17beta concentrations were higher in the estrous period than in the post-estrous period, while fecal progesterone concentrations were higher in the post-estrous period than in the estrous period. The similar trends of steroid hormone changes were observed in the non-mated females.

Reproductive pattern of the sun bear (Helarctos malayanus) in Sarawak, Malaysia.

Fecal progesterone assays were conducted in 3 captive female sun bears (Helarctos malayanus) segregated from males to characterize the species-specific reproductive pattern in their original distribution area in Sarawak, Malaysia. Peaks of fecal progesterone concentrations were observed once annually, and lactation was observed after increasing progesterone concentrations in all females without mating stimulus. These results suggest that sun bears in Sarawak, Malaysia, may have a seasonal reproductive pattern and ovulation was noted to occur spontaneously, followed by pseudopregnancy.