On the Use of the Perineal Stain as an Index of Sexual Maturity and Breeding Condition in the Male Greater Cane Rat,Thryonomys swinderianus,Temminck

The efficacy of the perineal stain as an index for sexual maturity and breeding condition in the male greater cane rat, Thryonomys swinderianus, Temminck, was investigated in 34 animals collected from hunters' kills in the Ekumfi District of Ghana, between April and June 1989. The results indicated that, although the presence of the perineal stain was conclusive proof of sexual maturity in an individual, it was not efficacious as an index for sexual maturity for biological work in these animals (p>0.05), because it excluded some that, although sexual mature, did not exhibit the trait, particularly young adults. However, the perineal stain may be useful as a management tool for identifying sexually mature captive greater cane rats. About 7 out of every 10 caught each month were found to be in breeding condition.     

Seasonal changes of testicular weight, sperm production, serum testosterone, and in vitro testosterone release in Korean ring-necked pheasants (Phasianus colchicus karpowi)

To study the biology of reproduction of male Korean ring-necked pheasants kept under natural conditions of temperature and photoperiod, testicular weight, serum testosterone concentrations, testosterone release from the luteinizing hormone (LH)-stimulated testis in vitro and sperm production were measured. Significant changes associated with seasonal cycles were found. Testis weight decreased dramatically in August, remained low until February, rapidly increased from March to high levels to June, and decreased subsequently. Serum testosterone concentrations remained little from August until February, but increased sharply in March to reach the highest levels in April. Thereafter, the concentrations decreased significantly from June. The testosterone release was low from August to February, increased abruptly in March to reach the highest levels in May, and showed rapid decrease thereafter. Sperm production decreased to nondetectable levels from August to February, increased markedly in March, reached a peak in May, and sharply decreased thereafter. Thus, the pheasants breed from late March to late June. These results indicate that the Korean ring-necked pheasant, under natural conditions, exhibits characteristics of a seasonal cycle in reproduction.     

Aspects of the reproductive biology of the southern mullet,Liza richardsoni,from Algoa Bay,South Africa

The reproductive biology of the southern mullet from Algoa Bay was studied between June 1978 and October 1980. Gonadosomatic indices and macroscopic and microscopic examinations of the gonads were used to establish the breeding cycle. The period of greatest sexual development extends from September to March and spawning occurred throughout that period. Spawning probably occurs close in shore. Liza richardsoni exhibited the phenomenon of group synchronism, two distinct oocyte groups being present within a pre-spawning ovary. The proportion of yolkless oocytes exceeded that of vitellogenic oocytes in ripe fish. However, it was not apparent whether all the vitellogenic oocytes would reach maturity. This highlights the need for quantitative histological studies to accompany fecundity estimates. Histological investigations were useful in the clarification of breeding cycle determinations based on gonadosomatic indices and visual macroscopic assessments.     

The Female Reproductive Cycle of the Neotropical Snake Atractus pantostictus (Fernandes and Puorto, 1993) from South‐eastern Brazil

Data on reproductive activity of fossorial species are limited because the specimens are difficult to be observed and captured. Here in, we present the reproductive cycle of female Atractus pantostictus, a fossorial neotropical species, and the sexual maturity of males and females in south‐eastern Brazil. The female reproductive cycle of A. pantostictus is seasonal, with vitellogenic follicles being found from September to April and eggs in November, February, March and April with the number varying between two and four. Spermatozoa were found in the lumen of the glandular and non‐glandular uterus in females collected during the rainy season. Sperm storage tubules were found in the posterior infundibulum of the females, where the storage of sperm occurs for a short time. The storage may occur because mating and ovulation are dissociated.     

Circulating testosterone and inhibin levels at different ages in the male beluga (Delphinapterus leucas)

This study is the first report on circulating testosterone and inhibin levels in a species of whales, the beluga. Circulating testosterone and immunoreactive (ir-) inhibin levels in two captive male belugas ("Nack", originally from Canada and "Duke", from the Okhotsk Sea) were measured every month for 9 years between 1995 and 2003. Assuming that clearly increased testosterone levels in the circulation indicates that the belugas had reached sexual maturity, at the ages of 10 ("Nack") and 11 years old ("Duke"). Their testosterone levels before the significant increase (pre-pubertal) were 0.42 ± 0.07 ng/ml (n=18) and 0.35 ± 0.10 ng/ml (n=18) and, those of after the increase (maturity) were 1.65 ± 0.14 ng/m l (n=74) and 2.06 ± 0.14 ng/ml (n=74). Circulating ir-inhibin levels before sexual maturity were 0.78 ± 0.04 ng/ml (n=18) and 0.64 ± 0.04 ng/ml (n=15) and, after sexual maturity were 0.52 ± 0.02 ng/ml (n=56) and 0.43 ± 0.02 ng/ml (n=67). Seasonal changes were observed in the testosterone levels after sexual maturity and the levels increased during March and April in Canadian origin "Nack", and peaked in February in Okhotsk origin "Duke". Circulating ir-inhibin level gradually decreased as they aged. A negative correlation between the circulating testosterone and ir-inhibin was observed. No seasonal changes were observed in the ir-inhibin levels after sexual maturity. These data will surely correspond to clarification of endocrinology and the successful reproduction of the beluga.     

Sexual Activity Influences the Secretion of Reproductive Hormones in the Stallion

Contents The aim of this study was to investigate the effect of sexual activity on concentrations of reproductive hormones in plasma of stallions. In the first experiment, two groups of stallions were monitored for secretion of luteinizing hormone (LH), testosterone and oestradiol from the beginning until shortly after the end of the breeding season. One group of animals were reserve stallions not used for breeding (group 1, n = 10), the other group consisted of active breeding sires (group 2, n = 8). Blood samples were withdrawn from March to August at 14-day intervals. In sexually nonactive stallions (group 1), seasonal variations in LH, testosterone and oestradiol occurred and concentrations of these hormones reached a maximum in May (p < 0.05). In the breeding stallions (group 2), no significant changes in the concentrations of these hormones were found between March and August. Concentrations of LH and testosterone were significantly lower in breeding stallions than in reserve stallions at most blood sampling times (p < 0.05). In the reserve stallions, oestradiol concentrations were significantly higher than in the breeding stallions in April and in June (p < 0.05). In a second experiment, the effect of regular sexual activity (semen collection three times per week) on the concentration of LH, testosterone and oestradiol was tested in a group of breeding stallions after a period of sexual rest for several weeks. Blood samples were taken once daily starting the day before the first semen collection was performed. Testosterone concentration significantly decreased in the first days after semen collection started (p < 0.05), while LH secretion was only transiently decreased and no effects on oestradiol concentration were found. In both experiments, semen parameters were within the normal range of fertile stallions. No correlations between the sexual drive of the stallions and concentration of reproductive hormones occurred. It can be concluded that in the stallion the secretion of reproductive hormones is influenced by sexual activity. Regular semen collection seems to inhibit testosterone release by unknown mechanisms while the effects on LH and oestradiol secretion are less pronounced.     

笼养羚牛繁殖生物学的初步研究

对上海动物园笼养羚牛种群20 a间的繁殖记录进行了统计分析,并将笼养羚牛和野生羚牛的各项繁殖指标进行了比较分析。结果表明：笼养条件下出生的雌性和雄性羚牛个体的首次成功繁殖年龄分别为4岁和5岁;笼养条件下出生的羚牛包括26只雌性和11只雄性,雌雄性比为2.36：1;羚牛的出生主要集中在1～4月,3月出生的个体最多;笼养羚牛首次繁殖年龄和幼仔出生季节与野生羚牛不存在显著差异。上述研究结果表明,影响羚牛繁殖的因素主要包括气候、环境、温度和湿度等。     

Serial Transrectal Ultrasonography for Monitoring the Reproductive Activity of the Asiatic Black Bear (Ursus thibetanus ussuricus)

This study evaluated the structural changes in the reproductive tract of Asiatic black bears using serial transrectal ultrasonography. In addition, the ultrasonographic observations were compared with the results of vaginal cytology and hormonal analyses. The collection of blood for hormonal analysis, vaginal cytology and transrectal ultrasonography was performed in two bears (Bears 1 and 2) from June 2011 to August 2013 without mating and in a third bear (Bear 3) from April to December 2012, allowing natural mating. Serial ultrasonographic observations showed cyclic changes in ovarian structures (e.g. emergence of small follicles, growth and ovulation of dominant follicles and corpus luteum (CL) formation) during the reproductive cycles of the three bears. The diameter of the uterine horns remained similar throughout the reproductive cycle in Bears 1 and 2, and it remained similar from April until October, but an enlargement containing foetuses was observed in Bear 3 in December. The ultrasonographic observations were consistent with the data obtained through vaginal cytology and progesterone analysis during the reproductive cycle. An average of 4.0 (±0.4) dominant follicles was observed during the oestrous stage (May‐August), during which the superficial cells accounted for >90% of the total vaginal cells. In addition, the detection of an average of 2.6 (±0.2) CL was associated with increased plasma progesterone concentrations (3.0 ± 0.4 ng/ml) between June and December (near hibernation). In conclusion, serial transrectal ultrasonography demonstrated yearly oestrous (ovulation) cycles via follicular dynamics and CL formation on ovaries, accordingly with vaginal cytology and hormonal level in the Asiatic black bear.     

笼养丹顶鹤繁殖行为和粪样中性激素水平变化的关系

2007年3月～2008年2月,在哈尔滨北方森林动物园,选2对健康的成年丹顶鹤,采用目标取样和扫描取样相结合的方法进行了行为观测,同时收取粪便提取激素,利用放射免疫分析法（RIA）测定了笼养丹顶鹤粪样中睾酮、孕酮、雌二醇的浓度。试验结果表明：笼养丹顶鹤繁殖行为呈显著的季节变化,其对鸣、炫耀行为的高发期在3、4月（P〈0．05）,营巢行为在3月极显著高于其他月份（P〈0．01）,丹顶鹤的交尾行为集中出现在3、4月（P〈0．05）;繁殖期雄性丹顶鹤粪便中睾酮平均水平为（259．59±149．70）ng／dl,非繁殖期为（84．81±27．35）ng／dl,二者差异显著,繁殖期雄鹤求偶炫耀、交尾、卧巢等的发生频次与粪便中睾酮呈极显著相关（P〈0．01）,其对鸣、警戒以及营巢都与睾酮变化水平呈显著相关（P〈0．05）。繁殖期雌性丹顶鹤粪便中的孕酮平均浓度为（9．65±7。15）rig／m1,非繁殖期为（2．76±0．97）ng／ml,差异显著,繁殖期雌鹤粪便中的孕酮激素水平与其卧巢行为呈显著性相关（R=0．8848,P〈0．05）;繁殖期雌性丹顶鹤粪便中雌二醇平均浓度为（30．50±61．77）pg／ml,非繁殖期为（8．17±3．72）pg／ml,二者差异显著,繁殖期雌鸟雌二醇变化水平与其繁殖行为的相关性不显著（P〉0．05）;雌性丹顶鹤粪样中雌二醇激素的变化水平与其产卵时间有着较为密切的关系。     

Fluctuations in serum steroid hormone concentrations and body mass during growth and sexual maturation in captive northern fur seals (Callorhinus ursinus)

Northern fur seals (Callorhinus ursinus) have a distinct life history pattern comprising annual terrestrial breeding and oceanic migration, and the physiological changes associated with these patterns are of particular interest for understanding their environmental adaptations. However, owing to their oceanic distribution, limited information is available on the reproductive physiology of wild individuals during the immature stage and the winter migration period. This study aimed to determine the relationships among the seasonal hormone profiles, body growth, age, and pregnancy using monthly serum samples collected over 3–5 years from two male and two female captive individuals during pubescence and sexual maturation. Small increases in the serum testosterone signaled puberty in males aged 3 and 4 years. Thereafter, males showed considerable increases in testosterone during breeding seasons, indicating sexual maturity. Immature female serum progesterone was maintained at low levels, but after pubescence, females showed an increase in serum progesterone in August, the month next to the peak of delivery, followed by a decrease. In non-pregnant females, progesterone did not increase significantly until the next breeding season, but in pregnant females, they increased again from February to March and then gradually decreased. Immature males increased body mass constantly and reached puberty when their body mass exceeded 20 kg, and they showed seasonal weight fluctuations after puberty. These results provide fundamental information for determining sexual maturity and pregnancy in this species based on sex steroid hormones and body mass measurements.     

Steroid hormone secretion during the ovulatory cycle and pregnancy in farmed Alaskan reindeer

Seasonal endocrine changes in 5 non-bred and 10 pregnant Alaskan reindeer have been documented. Blood samples were collected from early September until early May, spanning the breeding season, gestation, or the anovulatory period. Plasma was analyzed by RIA for progesterone (P4), estradiol-17beta, estrone, and estrone sulfate. Elevated P4 in 80% of the reindeer at the onset of the study indicated that ovarian activity had been initiated. The median date for the onset of the first recorded full-length ovulatory cycle was September 23. In nonbred reindeer, the mean ovulatory cycle length from September to May was 24 +/- 1 d (range 18 to 29 d). Nonbred females continued to cycle throughout the winter, displaying 6 to 8 ovulatory cycles after the beginning of blood sampling. Cycle length (mean 22 to 24 d) did not vary between individuals (P = 0.170) or over the course of the winter (P = 0.244). In early April, ovulatory cycles ceased with normal demise of the corpus luteum in 2 females, whereas the remaining 3 females formed apparently persistent corpora lutea. Natural service breeding occurred between September 10 and October 2, and P4 profiles indicated that all breeding females conceived to the first mating. Concentrations of P4 rose steadily after conception and remained elevated throughout gestation, with mean concentrations not varying significantly (P = 0.104) from 4 to 28 wk of gestation. Estrogens all followed patterns similar to each other, remaining at baseline concentrations until approximately 24 wk of gestation and rising coincidently as P4 declined just before parturition. There was a continual overlap throughout the winter in peak P4 concentrations observed in cycling and pregnant reindeer. Calving occurred between April 8 and May 2, resulting in a mean gestation length of 211 +/- 2.2 d (range 198 to 221 d). Information from this study can be used by Alaskan reindeer producers to improve management and profitability of reindeer production.     

Reproduction and Development of the Released Przewalski’s Horses (Equus przewalskii) in Xinjiang,China

In China, the first Przewalski’s horse (Equus przewalskii) group was released in Kalamaili Ungulate Protected Area in Xinjiang, in August 2001. The objective of this study was to investigate reproduction and development of released Przewalski’s horses in Xinjiang, China from 2002 to 2006. Twenty-four descendants were naturally born, average reproduction rate was 38.7%, and average survival rate of foals was 69.1% in this interim. Frequent alternation of the leading stallion and infertility in female horses due to environmental factors were main causes for the low reproduction rate. The infant mortality rate of released Przewalski’s horses was 25.0%, and 83.3% of death in infants was due to the leading stallion infanticide. The released Przewalski’s horses exhibited seasonal breeding, 70.8% of infants were born in May and June. The fertility rates were 8.3% in April and 37.5% in May, which were lower compared to those of the captive Przewalski’s horse groups (18.3% and 44.3%, respectively). Furthermore, the fertility rate in June was 33.3% and higher than the captive groups (18.3%). These findings showed that the breeding peak of the released Przewalski’s horse groups was later than the captive groups, and suggested that the altered survival environment and food supplies were the main reasons contributing to the delayed breeding peak.     

Reproductive Patterns in the Non‐Breeding Season in Asinina de Miranda Jennies

This study aims to characterize the reproductive patterns in Asinina de Miranda jennies during the non‐breeding season. Reproductive activity was surveyed in 12 females, aged between 3 and 18 years old, using ultrasound and teasing with a jack. The animals were monitored from September to April, six in each consecutive year. Of these 12 females, nine showed disruption to the normal pattern of ovarian activity during the non‐breeding season. Loss of normal cyclicity included anoestrus (41.7%), silent ovulatory oestrus (25%), and persistence of corpus luteum (8.3%). Only three females maintained a regular cyclic pattern with oestrous behaviour during the non‐breeding season. Anoestrus began in early November and lasted for an average of 147 ± 28 days (113–191 days), ending near to the spring equinox. Onset of silent oestrous cycles began more erratically, between October and February. In both groups the first behavioural ovulation of the year occurred around the time of the spring equinox. Disrupted reproductive activity was preceded by a shorter oestrous cycle only in females entering anoestrus. The mean follicle size in the first ovulation of the year was larger than in the reproductive season (44.7 ± 2.45 mm vs 39.2 ± 3.60 mm) in anoestrous jennies with protracted oestrus. Though age and body condition score (BCS) were associated, changes in BCS below a threshold of four points (for anoestrus) and five points (for silent oestrus) contributed greatly to disruption of reproductive cycles. BCS in females with regular oestrous cycles during the winter season remained unchanged or exceeded five points prior to the winter solstice.     

南阳牛母牛繁殖生理及应用

依据南阳牛保种场母牛繁殖资料和配种实践,总结出南阳牛性成熟和适配年龄、发情季节、发情周期、发情持续期、产后发情、左右侧卵巢机能等发情生理特点,在生产上用于母牛发情鉴定,以提高母牛繁殖率。     

Basal body temperature method for detecting ovarian cycle in the Captive Beluga (Delphinapterus leucas)

The relationship between basal body temperature and circulating progesterone levels were investigated in a female beluga. Body temperature and serum concentrations of progesterone were measured daily and at 2-4 week intervals respectively, in a female beluga that was in captivity for 7 years between 1996 and 2003. The beluga first ovulated in April, 2000 (13 years old). Thereafter, serum concentrations of progesterone showed cyclic changes, indicating that the ovulatory cycle had started. Serum concentrations of progesterone ranged from 0.1 ng/ml to 15.7 ng/ml. Body temperature also showed cyclic changes during the estrous cycle. Body temperature ranged from 34.9 to 35.9 C, and tended to reach the peak during the high progesterone phase. Mating behavior was observed during the low body temperature phase. The changes in body temperature positively correlated with the circulating progesterone levels. The length of the estrous cycle was 36.7 +/- 3.9 (mean +/- SEM) days based on the intervals between the days of mating behavior. This is the first report demonstrating that body temperature clearly changes during the estrous cycle in a captive female beluga. The present finding suggests that measurement of body temperature is a useful method for detecting the ovarian cycle of the beluga in captivity.     

Reproductive phenology of Creole horses in Ecuador in the absence of photoperiod variation: The effects of forage availability and flooding affecting body condition of mares

Horse reproduction tends to be seasonal. The main adjusting factor in their original temperate ranges is photoperiod variation, although it is absent in equatorial areas where horses were introduced by European colonizers. Hence, dates of reproduction in these areas may be influenced by factors affecting mares’ conditions and the success of foaling. Here we study reproductive timing in Creole horses in Ecuador reared in an extensive production system. We found that foaling peaked in August. Mares’ conditions showed one peak in June‐July, before the start of the breeding season, and another in December, and it was highly variable along the year. Mares’ conditions increased after a period of vegetation growth and thus appeared negatively associated with the increment of grass greenness (normalized difference vegetation index data). Seasonal flooding of some pasturelands during March and April appeared to seriously impair mares’ conditions and probably influenced the timing of foaling toward the dry season. Our results evidenced that horse breeding in these equatorial areas tended to be seasonal and point to some key factors that influence phenology by affecting body condition of mares, which may have implications for horse biology and management.     

环尾狐猴的饲养繁殖与人工育幼技术

2010年,对吉林省东北虎园所饲养的环尾狐猴进行了饲养繁殖方面的研究。从环尾狐猴的日粮配制、繁殖行为、人工育幼等方面入手,就笼养条件下环尾狐猴的饲养繁殖进行了较系统地阐述,以期为饲养繁殖环尾狐猴提供参考和借鉴。     

Season- and Age-related Reproductive Changes Based on Fecal Androgen Concentrations in Male Koalas,Phascolarctos cinereus

The purposes of the present study were to clarify age- and season- related androgen patterns, and to compare the reproductive physiology between Japanese captive koala populations and Australian populations. To measure fecal androgens, feces were collected from male koalas (4.2 to 13.8 years of age) kept in Japanese zoos. Fecal androgens were extracted with methanol from the lyophilized samples and determined by enzyme immunoassay using 4-androstene-3,17-dione antibody. Fecal androgen concentration in male koalas increased after sexual maturation and remained relatively high until old age. In the survey with the Japanese zoo studbook of koalas, copulation (conception) month showed a pyramid shape with a peak in March to June (60.7%) in koalas born and reared in Japanese zoos and from July to April with the highest concentration in September to January (69.7%) in Australian institutes. Japanese zoo koala populations have a characteristic physiological cycle adapted to Japan''s seasonal changes. The suitable month of year for copulation or conception in Japan is diametrically opposed to that in Australia. Mean fecal androgen concentrations by month in the males born and reared in Japan indicated annual changes with the highest concentration in May and the lowest value in November. Fecal androgen analysis may be a noninvasive alternative tool to monitor circulating testosterone and may be helpful in understanding reproductive activity and physiology in male koalas.     

The reproductive performance of Finn × German Mutton Merino and purebred German Mutton Merino Ewes

The sexual season, i.e. the sexual cycle activity, of Finn × German Mutton Merino (Finn × GMM) ewes was found to extend from August to March. In a group of purebred German Mutton Merino (GMM) ewes the sexual season extended from June to January.After July–August and October–November lambings, 90–95% of the Finn × GMM crosses renewed postpartum sexual activity within 90 and 75 days, respectively. Only 40% of the November lambing purebred GMM ewes started new cycles within 105 days postpartum.The responsiveness of the Finn × GMM ewes to hormonal treatment was high (90–100%) during different months of the year. The fertility at the synchronized or induced oestrus was 60–75% throughout the year, with a mean litter size of 2.0 lambs per lambing.     

The Correlation between Age,Body Weight and Testicular Parameters in Murrah Buffalo Bulls Raised in Brazil

Buffalo are an economically important source for meat and milk production, especially in Brazil. However, important aspects of their biology remain unknown thus far. Herein, we describe the reproductive characteristics of male Murrah buffalo (Bubalus bubalis) raised under extensive management conditions by applying biometrics associated with testicular weight. We analyzed seven males, divided into two groups: G1, which consisted of four 18-month-old animals, and G2, which consisted of three 24-month-old animals. Testicular development occurs slowly in Murrah buffalo, suggesting a delay of sexual maturity. The biometric testicular parameters analyzed were scrotal circumference, testicular weight, testicular length, testicular width, testicular thickness and testicular circumference. Our data indicate strong correlations between SC, age and body weight, and additional significant relationships were identified between body weight, age and other testicular parameters. Thus, these parameters are suitable indicators when selecting bulls for breeding purposes.