Primiparous Age Research Articles

Population Characteristics of Feral Horses Impacted by Anthropogenic Factors and Their Management Implications

Feral horses form relatively stable harems over time that are characterized by long-lasting bonds among their members, a characteristic that makes them an exceptional case of a social system among terrestrial ungulates. Their social system has been described as uniform despite the wide differences in their environment and demography. Horse populations subjected to human interference often show higher levels of population instability that can ultimately compromise their reproductive success. In this article, we describe demographic and dynamic changes of a Portuguese population of Garranos in Serra d’Arga (SA), which is impacted by human and predation pressures, over six breeding seasons. Furthermore, we tested several hypotheses related to the impact of anthropogenic disturbance on the structure and dynamics of this population. Our results revealed that the SA population had relatively little human interference at the start of the project in 2016. This was supported by the natural composition of the herd (total number of individuals, 206), which consisted of several single- and multi-male harems (n= 17 and 7, respectively) and bachelor males (n= 9). However, from 2017 to 2021, SA’s Garrano population suffered a drastic decline. Approximately two-thirds of the individuals and all bachelor males disappeared, and 76% of adult female transfers occurred after the death or disappearance of the harem male. Predatory pressures and poor management of the population, which allowed illegal human interference, contributed to this population crisis. A low population growth rate, reduced birth and foal survival rates, in addition to a delayed primiparous age were observed in this population and exacerbated after its drastic decline; suggesting the viability and survival of this Garrano population were compromised. Investigating the population demographic changes and their causes and consequences can provide guidelines for managing populations and help fight the extinction of horse breeds.

Investigation on factors related to uterine fibroids in rural women of northern Anhui province.

Given the increasing prevalence of hysteromyoma among the Chinese rural women of childbearing age, it is imperative that more attention should be given to researching risk factors that predispose women to this condition so that early preventive measures may be taken. Our study investigates potential risk factors for uterine fibroids such as participants' demographic characteristics (age, ethnicity, education), physiological characteristics (age at menarche, primiparous age), and the occurrence of several different female reproductive diseases (vaginitis, pelvic inflammatory disease). 2200 rural women of reproductive age were screened from a cross-sectional study carried out in the northern Anhui province. Data were collected by questionnaire surveys, gynecological and laboratory examinations and were subjected to univariate and multivariate analysis to evaluate the risk factors for uterine fibroids. Of the 2200 women, 440 had uterine fibroids. In general, women with endometriosis, ovarian cysts and early menarche were more likely to suffer from hysteromyoma. Factors including higher parity, late age of first childbirth, and a regular menstrual cycle were associated with the reduced risk of uterine fibroids. Our findings indicate that parameters such as earlier age of menarche, early primiparous age, lower parity and a variety of female reproductive diseases were associated with an increased risk of uterine fibroids. These findings may be used to guide the formulation of effective prevention and intervention protocols to improve the reproductive health of rural women.

Prognosis of stage III cervical cancer: a two-way outcome study.

BackgroundCervical cancer is the second most common female malignancy worldwide, and the prognosis of patients with the locally advanced stage is poor, with a high risk of recurrent. This study aimed to explore the effect factors that influence the overall survival (OS), progression-free survival (PFS), and quality of life in patients with stage III cervical cancer.MethodsA two-way follow-up method was utilized to collect information from patients with stage III cervical cancer. Survival analyses were performed by the Kaplan-Meier method and Cox regression model. Multiple linear regression was used to analyze the factors related to quality of life.ResultsFour hundred and sixty subjects were enrolled in this study. The median follow-up time was 28 months (range, 1–51 months). The 3-year OS and PFS rates were 69.0% and 55.0%, respectively. Primiparous age above 30 years, age at diagnosis below 40 years, lymph node metastasis, non-squamous cell carcinoma, and larger tumors were risk factors of OS and PFS, while the protective factors were weight loss, good mental status, and standardized treatment. The quality of life was better in patients with the following characteristics: younger age at diagnosis, active review according to medical orders, and earlier return to society.ConclusionsPrimiparous age above 30 years was a poor prognostic factor for OS, PFS, and quality of life. The common factors relevant to prognosis were confirmed to be significant.

Characteristics of positive-interaction parenting style among primiparous teenage, optimal age, and advanced age mothers in Canada

BackgroundPositive-interaction parenting early in childhood is encouraged due to its association with behavioural development later in life. The objective of this study was to examine if the level of positive-interaction parenting style differs among teen, optimal age, and advanced age mothers in Canada, and to identify the characteristics associated with positive-interaction parenting style separately for each age group.MethodsThis was a cross-sectional secondary analysis of the National Longitudinal Survey of Children and Youth. First-time mothers with children 0–23 months were grouped into: teen (15–19 years, N = 53,409), optimal age (20–34 years, N = 790,960), and advanced age (35 years and older, N = 106,536). The outcome was positive-interaction parenting style (Parenting Practices Scale); maternal socio-demographics, health, social, and child characteristics were considered for backward stepwise multiple linear regression modeling, stratified for each of the age groups.ResultsTeen, optimal age, and advanced age mothers reported similar levels of positive- interaction parenting style. Covariates differed across the three age groups. Among optimal age mothers, being an ever-landed immigrant, childcare use, and being devoted to religion were found to decrease positive-interaction parenting style, whereas, higher education was found to increase positive-interaction parenting style. Teen mothers were not found to have any characteristics uniquely associated with positive-interaction parenting. Among advanced age mothers, social support was uniquely associated with an increase in positive-interaction parenting. Very good/excellent health was found to be positively associated with parenting in teens but negatively associated with parenting in advanced age mothers.ConclusionCharacteristics associated with positive-interaction parenting varied among the three age groups. Findings may have public health implications through information dissemination to first-time mothers, clinicians, researchers, and public health facilities.

Slow intrinsic growth rate in forest elephants indicates recovery from poaching will require decades

Summary African forest elephants Loxodonta cyclotis are experiencing persistent declines driven by illegal killing and range loss. Despite the importance for policy debates regarding elephant trade managed through the Convention on International Trade in Endangered Species (CITES), little is known about forest elephant demography and, consequently, the impacts of offtake and subsequent population recovery potential. Using 23 years of individually based demographic data from Dzanga, Central African Republic, we found low reproductive potential resulting from annual birth rates averaging 4·3% (SD: 1·4%), a median inter‐birth interval of 68 months and a median primiparous age of 23 years. Average mortality was 3·1% per year (SD: 1·0%) during the study, with approximately 1·4% of that attributed to human killing. This population of forest elephants demonstrated concerningly slow growth rates, with a doubling time of nearly 60 years under current conditions (41 years excluding human impacts), amounting to three times that reported for savanna elephants. As such, forest elephants appear to be significantly more sensitive to human‐induced mortality than their congeneric species. Such slow intrinsic growth challenges current perceptions of historic and contemporary ivory trade impacts on forest elephants, highlighting the urgent need to stem poaching and institute long‐term protective measures. Policy implications. Debates regarding the sustainability of the ivory trade for the species appear to have overestimated growth rates of forest elephants. The information presented here indicates that sustainable offtake models for forest elephants need reassessment.

Use of ecotoxicological and genotoxicity assays to assess the water quality of the river Cubatão (Santa Catarina, Brazil), as a means of monitoring the water quality of the Babitonga Bay

Use of ecotoxicological and genotoxicity assays to assess the water quality of the river Cubatão (Santa Catarina, Brazil), as a means of monitoring the water quality of the Babitonga Bay

Fatores materno-infantis associados à diástase dos músculos retos do abdome no puerpério imediato

Objetivos: comparar a distância entre os músculos retos do abdome (MRA) e a prevalência da diástase (DMRA) nas regiões supra-umbilical e infraumbilical de primíparas e multíparas no pós-parto imediato e verificar quais fatores materno-infantis podem estar associados. Métodos: estudo transversal, incluindo 115 primíparas e 154 multíparas. Avaliou-se a DMRA 4,5 cm acima e abaixo da cicatriz umbilical. Correlacionouse com idade materna, índice de massa corporal (IMC), idade gestacional, peso, estatura, perímetro cefálico e torácico do recém-nascido (RN). Utilizouse test t de Student, correlação de Pearson, quiquadrado e regressão logística múltipla, p<0,05. Resultados: a distância entre os MRA supraumbilical foi 3,04 (±1,68) e 3,35 (±1,19) cm nas primíparas e multíparas. A prevalência da DMRA supra-umbilical foi 74,8% e 76,6% e, infra-umbilical 40,0% e 54,5%. Nos dois grupos observou-se correlação positiva da distância entre os MRA supraumbilical com idade materna, IMC e infra-umbilical. O IMC e peso do RN foram fatores associados à DMRA supra-umbilical na primíparas e a idade materna nas multíparas. Conclusões: independente da paridade, a distância entre os MRA e prevalência da DMRA foram maiores na região supra-umbilical e, correlacionou-se com idade materna, IMC e infra-umbilical. Nas primíparas os fatores associados foram IMC e peso do RN e nas multíparas, a idade materna.

Comparative Demography of an At-Risk African Elephant Population

Knowledge of population processes across various ecological and management settings offers important insights for species conservation and life history. In regard to its ecological role, charisma and threats from human impacts, African elephants are of high conservation concern and, as a result, are the focus of numerous studies across various contexts. Here, demographic data from an individually based study of 934 African elephants in Samburu, Kenya were summarized, providing detailed inspection of the population processes experienced by the population over a fourteen year period (including the repercussions of recent increases in illegal killing). These data were compared with those from populations inhabiting a spectrum of xeric to mesic ecosystems with variable human impacts. In relation to variability in climate and human impacts (causing up to 50% of recorded deaths among adults), annual mortality in Samburu fluctuated between 1 and 14% and, unrelatedly, natality between 2 and 14% driving annual population increases and decreases. Survivorship in Samburu was significantly lower than other populations with age-specific data even during periods of low illegal killing by humans, resulting in relatively low life expectancy of males (18.9 years) and females (21.8 years). Fecundity (primiparous age and inter-calf interval) were similar to those reported in other human impacted or recovering populations, and significantly greater than that of comparable stable populations. This suggests reproductive effort of African savanna elephants increases in relation to increased mortality (and resulting ecological ramifications) as predicted by life history theory. Further comparison across populations indicated that elongated inter-calf intervals and older ages of reproductive onset were related to age structure and density, and likely influenced by ecological conditions. This study provides detailed empirical data on elephant population dynamics strongly influenced by human impacts (laying the foundation for modeling approaches), supporting predictions of evolutionary theory regarding demographic responses to ecological processes.

Changes in Demographic Parameters of Macaca fuscata at Takasakiyama in Relation to Decrease of Provisioned Foods

Though researchers have studied population dynamics extensively in many free-ranging primate populations, information on the relationship between food abundance and demographic parameters based on long-term data is sparse. We examined changes in demographic parameters in relation to decreased provisioning of foods based on data gathered for >50 yr in a provisioned, free-ranging Japanese macaque (Macaca fuscata) population at Takasakiyama, Oita Prefecture, in the southern region of Japan. At Takasakiyama, population size increased linearly because of heavy provisioning in the 1950s and 1960s. The provisioning of food to macaques decreased from 1965. We examined changes in the physique index of full adult females, primiparous age, birth percentage, infant mortality rate, population density, and annual population growth rate relative to the decrease of provisioned foods between the 1970s and 1990s. As a result of the drastic decrease in the amount of foods provisioned, the physique index of full adult females decreased, primiparous age increased, birth percentage decreased, and infant mortality rate increased, such that annual population growth rate diminished substantially. Ours is the first study to demonstrate quantitatively the relationship between provisioned food abundance and demographic parameters based on long-term data.

Factors Influencing the Well-Being and Longevity of Captive Female Orangutans

I examined factors affecting the health and mortality of female orangutans in captivity and identified specific aspects of husbandry that appear to be critical to long-term survival in captivity. There are certain high-hazard events in the life of a captive female orangutan, including birth and parturition. Other than the short periods of high hazard, and perhaps of more significance to long-term survival, the major factors that appeared to influence long-term health and mortality included primiparous age, interbirth interval, rearing type, and weight.

Milk composition of “Nero Siciliano” sow. Preliminary results

Quantitative and qualitative milk production is the basis for determining the nutritional requirements of lactating sow; indeed, the gross nutrient composition of sow’s milk is frequently used as a suitable starting point when formulating milk-replacer diets for piglets. Data about the sow’s milk can be found from the literature but, in authors knowledge, no data on milk composition of Nero Siciliano sow exist. This study reports the preliminary results concerning some physical and chemical characteristics of the milk of this autochthonous Sicilian pig race during the lactation.The research was carried out on 10 “Nero Siciliano” sows, 4 primiparous (age: 9-12 months) and 6 pluriparous (age: 2-5 years), stabled in single boxes and fed with a concentrate. From the 10th day after farrowing to the weaning (day 58th), every week, in the morning, the sows were injected with 5 IU oxytocin (i.m.) and hand-milked; all functional mammary glands were milked. Piglets were removed and isolated from the dams for at least 30 min before each milking. Individual milk samples were analysed to determine: pH value, protein (Kjeldhal methods, N x 6.38), fat (Gerber method) and lactose (HPLC method) content; the energy content, expressed in kJ?kg-1 of milk, was calculated using the coefficients reported by Perrin (1958). Data were collected in relation to the stage of lactation in three periods called: “First” (day 7 to 22), “Medium” (day 23 to 38) and “Final” (day 39 to 58) and subjected to ANCO-VA considering as main variable the stage of lactation and as covariate the age (proc. GLM; SAS, 2001). As regards the pH of the milk, no significant differences were observed during the lactation (“First”: 7.14; “Medium”: 7.07; “Final”: 7.27); the mean values were slightly higher than those observed by Others in hybrid pigs. Fat percentages showed significant differences between the “First” and the “Medium” (P<0.001) and the “First” and the “Final” (P=0.012) periods of the lactation, with the highest value at the “First” period (8.68%) followed by a decrease as lactation progressed (“Medium”: 6.34%; “Final”: 7.09%). As regards protein percentages was similar to that of fat, but no significant differences were observed among the three periods of lactation (“First”: 5.48%; “Medium”: 4.72%; “Final”: 5.94%). The mean values of fat and protein percentages as well as their trends are in accordance to those observed by other Authors on white pig races. Lactose, the major carbohydrate in sow’s milk, has shown a linear increase during the whole lactation with the lowest value in the milk of the “First” (4.40%) period and reaching significant differences (P=0.008) at the “Final” period with the highest percentage (6.22%). These results are not in accordance to those reported in literature. The energy content (kJ?kg-1) showed a trend (“First”: 5161; “Medium”: 4525; “Final”: 4864) similar to that observed for fat percentage with significant differences between the “First” and the “Medium” (P=0.005) and the “Medium” and the “Final” (P=0.029) periods.The knowledge of the milk composition of Nero Siciliano sow, characterised by low prolificacy (7±3 piglets), represents a critical point for a better estimation of the requirements of lactating sows as well as of piglets.

Obstetric anal sphincter rupture in older primiparous women: a case–control study

To determine if maternal age (35 years of age or older) in primiparous women is a risk factor for the development of obstetric anal sphincter rupture (OASR) and to identify obstetric factors associated with it. This is a retrospective case-control study. The study population was made up of the 5,345 primiparous women aged 24-45 years who delivered vaginally with singleton live-born neonates during 1990-99 at the Department of Obstetrics and Gynecology, Linköping University Hospital, Sweden. As cases the 327 primiparous women aged 35-45 years at delivery were selected. For each case two primiparous controls ten years younger were selected, matched for gestational age and year of delivery, in all 654 controls. Maternal, obstetrical, and neonatal data were obtained from the delivery records. Obstetric factors for the development of OASR were assessed with multivariate logistic regression analysis. No significant association was found between the primiparous age category and OASR. Vacuum extraction, forceps delivery, and the head circumference of the neonate were found to be independent risk factors for OASR, while the use of mediolateral episiotomy or epidural analgesia were independent protective factors for developing OASR. Primiparous women, 35 years of age or older, do not seem to have a greater risk of OASR than younger primiparous women. Risk factors for OASR are instrumental vaginal delivery and the size of the neonate. Mediolateral episiotomy and epidural analgesia seem to reduce the risk for OASR.

Preeclampsia in twin gestations: Association with IVF treatments, parity and maternal age

Objective. To identify maternal factors that increase the risk of preeclampsia in twin gestations and to investigate whether twins conceived by in vitro fertilization (IVF) lead to an increased risk of preeclampsia development.Materials and methods. A retrospective population-based cohort study of twin deliveries was performed. Maternal characteristics and perinatal outcomes were evaluated. Patients' data were obtained from a computerized database and analyzed using SPSS statistical package.Results. During the study period there were 2628 twin deliveries, and of these 3.1% had severe preeclampsia and 6.16% mild preeclampsia. Patients with severe preeclampsia were more likely to be primiparous, and to have significantly higher frequency of chronic hypertension, gestational diabetes mellitus (GDM), IVF treatments, cesarean delivery, preterm delivery and twin discordancy than in the normotensive patients. Chronic hypertension, pirimiparity, twin discordancy and maternal age were independent risk factors for the development of preeclampsia. In a multivariate regression model including IVF treatment, parity and maternal age as risk factors for preeclampsia, women younger than 35 years that conceived following IVF treatments had an independent risk factor for the development of preeclampsia.Conclusion. IVF treatments in primiparous patients and age younger than 35 years are independent risk factors for preeclampsia. Twin discordancy is an additional independent risk factor for the occurrence of preeclampsia.

Female age-specific reproductive rates, birth seasonality, and infant mortality of ring-tailed Lemurs on St. Catherines Island: 17-year reproductive history of a free-ranging colony

To compare reproductive parameters of a managed population of free-ranging provisioned ring-tailed lemurs (Lemur catta) to wild L. catta populations, we analyzed birth and mortality records collected over the 17-year history of the St. Catherines Island ring-tailed lemur colony. The majority of births in this colony (approximately 80%) occurred in March, which indicates that most females at this site conceived during the first estrus cycle of the breeding season, as do wild ring-tailed lemur females (Sauther [1991] Am J Phys Anthropol 84:463–77). Females in this provisioned colony reach the age at first parturition (primiparous age) earlier (at 2 years) than do wild ring-tailed lemurs, which typically begin to reproduce at 3 years of age (Sussman [1991] Am J Primatol 84:43–58; Koyama et al. [2001] Primates 42:1–14; Gould et al. [2003] Am J Phys Anthropol 120:182–94). Female fecundity is lowest at 2 years of age (34%), but increases to 67–100% for females age 3 and older. Survival analyses showed that infant survivorship for very young (2–3 years) and very old females (>10 years) are similar, and are lower than that for reproductively prime-aged females (4–9 years), although this trend is not statistically significant (χ2=3.18, df=2, n=125, P=0.203). There was a large amount of variability in infant survival rates among the oldest females, and a few older females (ages 13 and 14) still had high infant survival rates despite their old age. When compared to wild populations, provisioning in this island colony generally caused a decrease in the female primiparous age, a decrease in infant mortality, and an increase in multiple-offspring births (twins or triplets). Zoo Biol 0:1–15, 2005. © 2005 Wiley-Liss, Inc.

Demographic parameters and life history of chimpanzees at Bossou, Guinea.

Demographic parameters of wild chimpanzees at Bossou, Guinea, are presented and compared with those of other populations. The population size of Bossou chimpanzees has been stable over the last 26 years, except during two incidents of partial deforestation. The annual birth rate for a female (mean = 0.194, but 0.165 when the infant survived more than 4 years) and interbirth interval are not much different from those of other study sites. The primiparous age of Bossou chimpanzees, however, is far younger (mean = 10.9 years) than for all other known wild chimpanzee populations. The infant and juvenile survival rate is also the highest (female = 0.64, male = 0.52 for the first 8 years). As a result, the lifetime reproductive success of Bossou chimpanzees is estimated to be highest among long-term study sites. The rate of disappearance from Bossou dramatically increases during the adolescent stage, and most young chimpanzees disappear before or around maturation. Probably because the environmental capacity for chimpanzees at Bossou is at its limit, many young independent males, as well as females, have to disperse, though others may die. For chimpanzee alpha males of other populations, mature males may be needed as collaborators to defend resources. In the case of Bossou, however, a lack of adjacent groups, conspecific competitors, predators, and perhaps medium-sized mammals as prey for group hunting may eliminate this need of the alpha male for other males. The reasons why all males of other chimpanzee populations persist in being philopatric for life and maintain kin-related male bonds differing from most mammal species, including humans, are discussed.

Effect of age and dietary protein content on post-partum oestrous cyclicity in ewes lambing within their natural breeding season

Abstract The objective was to determine the effect of age and dietary protein content on onset and pattern of oestrous cyclicity in ewes lambing within their breeding season. Twenty-four multiparous (age 4.5 yr, se = 0.61) and 24 primiparous (age 1.5 yr, se = 0.00) ewes that had lambed on 28 Oct (se 0.2 d) and were rearing 2.0 and 1.9 (se 0.13) lambs respectively were allocated equally to 4 groups. From 3 Nov, each group was housed with a raddled vasectomised ram in a strawbedded pen under natural photoperiod at 57 °N and fed ad libitum hay plus 1.2 kg/head/d concentrate containing 12.5 MJ ME/kg DM and 180 or 120 g/kg CP. Blood samples were obtained 3 times/week from all ewes for determination of plasma progesterone (P4). Data were analysed using a General Linear Model. Mean liveweights for multiparous vs primiparous ewes at allocation were 80.0 vs 58.8 kg (se 1.46) and at weaning (18 Dec) were 72.7 vs 55.1 kg (se 1.65). Liveweight loss during lactation was affected by age (P 1 ng/ml in at least 2 consecutive samples), which commenced 14 to 43 days post-partum. Mean ± se days to onset of ovarian activity were 28.0 ± 1.53 vs 25.0 ± 1.50 for multiparous vs primiparous ewes and 26.5 ± 1.53 vs 26.6 ± 1.50 for ewes fed the 18 vs 12% CP concentrate. Within each group, 2 to 5 ewes experienced initial short luteal phases and 1 formed a persistent corpus luteum. Results demonstrate that (i) the strong seasonal drive for reproduction in sheep overrides the inhibitory effects of lactation; and ii) post-partum oestrous cyclicity is not influenced by age or dietary protein content within the range studied.

Lifelong Reproductive Performance and Fetal Development in Japanese Black Cows

The present study was carried out to establish the reproductive performance of Japanese Black Cows in their lifetimes. The major results were summarized as follows. 1)Fetal development: Growth of fetal body weight and crown-rump length was characterized for conceptuses ranging 39 to 268 days of gestation. 2)Growth of female genital tract from birth to puberty: Heifers whose body weight reached 257-269 kg, had matured sexually. Uterine and cervical weights at puberty, distributed 78. 0-139.0g and 22. 0-85.0g, respectively. The body weight of heifers showed continual increase after puberty, while there were a little increase in the uterine and cervical weight, and no growth of the oviduct either in weight or length. 3) Uterine involution postpartum: Primiparous Japanese Black Cows were slaughtered at 18, 23, 29, 46 and 54 days postpartum to examine the histological patterns of involution of uterus. At 18 and 23 days postpartum, the uterine endometrium contained many phagocytes and nodular aggregations of lymphocytes. Capillaries located under the surface epithelium were not yet completely contracted. At 46 and 54 days postpartum, however, the endometrium contained only a little amount of lymphocytes and phagocytes, uterine glands evenly distributed with a tall glandular epithelium. It may be concluded that uterine involution was completed histologically at approximately 40 days or later postpartum. Using the ultrasonic linear scanner, it was confirmed that uterine involution was completed at approximately 40 days postpartum. 4) Lifelong reproductive performance of Japanese Black Cows: The mean duration for the first postpartum estrus was 67.7 days. Mean time interval from parturition to conception, that was days open, was 125.5 days, so mean calving interval was 417.5 days. First and final calving ages of the cows were 2.53 and 8.14 years old on average, respectively, and they produced 5. 4 calves on average in their lifetimes. Cows in which primiparous age ranged from 2.01 to 3.00 years old, produced more calves (over 6) in their lifetimes than those in which primiparous ages was under 2.00 or over 3.01 years old. Rate of culled cows at every calving number reached to 51 and 83 % of total cows after fifth and eight calving number, respectively. Seventy eight % of the culled cows were due to some reasons of reproduc-tive disorders. A reasonable age for beginning of calf production in Japanese Black Cows was estimated to be in the range from 15 to 20 months old, and economical limit of age for reproductive use was estimat-ed to be 9 to 10 years old when they will have more than 8 calves.

Age-specific birth rate and lifetime reproductive success of chimpanzees at Bossou, Guinea.

Preliminary calculations of the age-specific birth rate for wild female chimpanzees were based on demographic records from a long-term study at Bossou, Republic of Guinea. Primiparous age was 12-14 years. Birth rate for a female reached a peak of 0.333 a year at 20-23 years, and then decreased until menopause at more than 40 years of age. Mean birth rate for a female of more than 12 years was 0.197 a year. Mean interbirth interval was 4.6 years overall, but 5.1 years, if all cases in which the previous infant had died within its first three years were excluded. Infant survival rate for the first four years was 0.727 and that of juveniles (four to seven years) was 0.714; however, that of adolescents (eight to 11 years) was only 0.222. Some adolescents who disappeared from Bossou are thought to have migrated to adjacent habitats. From age-specific birth rate and survival rate, the lifetime reproductive success was calculated as only 0.74 offspring per female. This rose to 2.39 when adolescent survival rate was assumed to be the same as that of juveniles. This must be less than the minimum reproductive success required for continued survival of the population. The recent and continuing degradation of the environment will lead to the extermination of this species from the area in the near future. © 1994 Wiley-Liss, Inc.

Inbreeding process and establishment of new inbred lines derived from the Japanese house mouse, Mus musculus molossinus

Inbreeding of 8 groups in molossinus mouse began in (Miura female x Urawa male) F1 (MU) from the stock captured in the Kanto district of Japan and were accomplished by each primiparous littermates. The animals were kept under a clean conventional condition at 23.5 +/- 2.5 degrees C and 50 +/- 5% in relative humidity. Pellet feed, CRF-1, and tap water were provided ad libitum. The respective number of inbreeding generations of MUA, MUF and MUG now exceeds F21, F20 and F22, respectively. Inbreeding of MUD and MUE have reached to F18 up to now, but the other 3 groups became extinct at F10. Time required for inbreeding from F0 to F20 was 2,280 days for MUA, 2,454 days for MUF and 2,143 days for MUG. Generation time was 114.0 +/- 47.2 days for MUA, 122.7 +/- 54.6 days for MUF and 107.2 +/- 48.5 days for MUG. Though the generation time varied from a minimum of 60 days to a maximum of 258 days from F0 to F10 in the inbreeding process (mean: 150.2 +/- 41.7 days), which were shortened from F10 and the mean was 79.0 +/- 29.1 days. In the breeding of the molossinus mouse, primiparous age was 124.5 +/- 29.7 days from F0 to F9 and 77.8 +/- 9.3 days from F10 to F19. The litter size was 5.1 +/- 1.3 for MUA and 5.0 +/- 1.3 for MUG in offspring, 5.0 +/- 1.2 and 4.9 +/- 1.2 in weanling, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristic features of the reproduction of Koshima monkeys,Macaca fuscata fuscata: A summary of thirty-four years of observation

The reproductive data for Japanese monkeys,Macaca fuscata fuscata, which had been recorded for the 34 years from 1952 to 1986 on Koshima, were analyzed in terms of the influence of changes in artificial food supplies, the differences in reproductive success between females, the timing of births, and the secondary sex ratio. Koshima monkeys increased in number until 1971 when the population density was still small and artificial provisioning was copious. As described byMori (1979b), the severe reduction in artificial food supplies, which began in 1972, had an enormous deleterious effect on reproduction: the birth ratio of adult females of 5 years of age or more fell from 57% to 25%; the rate of infant mortality within 1 year of birth rose from 19% to 45%; primiparous age rose from 6 to 9 years old on average; and there was an increased death rate among adult and juvenile females. The prolonged influence of “starvation” may be seen in the significantly delayed first births of those females that were born just before the change in food supplies. When reproductive parameters are compared between the females who belonged to six lineages in the group during these periods, they were found to be rather consistent, although some individual differences can be recognized among females and subgroups. The apparent trend was that some of the most dominant females retained superior reproductive success while that of the second-ranked females has tended to diminish over the years since 1972. Such opposing trends were seen only in the most dominant lineage group and such a difference was not recognized among the females of other lineages. The difference in reproductive success is discussed in relation to both the different situations that arise because of the artificial food supplies and differences in feeding strategies. Multiparous females, after a sterile year, gave birth somewhat earlier than those who reared infants in the preceding year and, when artificial provisioning was intense, they tended to give birth a little earlier than during other periods. There is some evidence that the mortality of later-born infants was higher than that of earlier-born infants after 1972. However, this difference may not be responsible for the differential reproductive success of females since the timing of births did not differ among lineages. Furthermore, during the time when many females gave birth continuously, prior to 1972, the infant mortality did not differ with respect to the timing of births. The differences in infant mortality were not correlated with the reproductive history, parity or age of the mother, or with the sex of the infant. The secondary sex ratio varied by only a small amount, from slightly male-biased ratio (114: 100) when correlated with reproductive history, parity, age of mother, sex and survival ratio for preceding infants, timing of birth, and lineage of the female. Furthermore, the change in artificial food supplies did not cause any modifications of the secondary sex ratios, despite its enormous deleterious effect on reproduction. The secondary sex ratio of Japanese monkeys may not be influenced by the social factors mentioned.