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"In the nineteenth century, the demographic development of the Meierij, a region in the south-east of the Netherlands, was different from that of the rest of modernizing northern Europe. Infant mortality remained high, while it dropped elsewhere. The article shows why the current explanation for high infant mortality, which links a sustained high infant mortality to a change in feeding habits is not valid. Increased fertility due, among other reasons, to a lower marital age offers a better explanation. Changes in economic options open to unmarried women provide the clue. With fewer premarital occupational possibilities, women would have been more inclined to marry, or there would have been less pressure on them to forestall a marriage in order to profit to the full from the occupational options. More and earlier marriages meant more children were born, and also a higher infant mortality rate."

O objetivo deste trabalho foi avaliar, através do exame andrológico, a capacidade e evolução reprodutiva de um rebanho de touros comerciais da raça Brangus destinados à reprodução por monta natural nos anos de 2010 e 2011. Neste trabalho foram avaliados no período de 2 anos, 393 touros desta raça com idades entre 16 e 21 meses (G1) e acima dos 32 meses (G2), através de exame andrológico completo. As medidas de circunferência escrotal (CE) do grupo etário G1 apresentou aumento significativo de 2010 para 2011, enquanto que no G2, não se observou diferença entre os períodos. Os animais apresentaram uma boa evolução reprodutiva, pois os índices de reprovação no exame andrológico observados em 2010 foram de 37% e 22% no G1 e G2, e 20% e 27% respectivamente em 2011, mas essa diferença entre os períodos não foi significante estatisticamente, permanecendo dentro da faixa de boa atividade reprodutiva. Ao término deste trabalho, observou-se o quanto é importante a realização de exames andrológicos periódicos, que possibilita identificar machos, cujos índices reprodutivos encontravam-se abaixo do preconizado como ideais para a espécie, e exclusão desses animais do programa de monta natural ou comercialização. Isso possibilita melhores resultados de fertilidade do rebanho e o melhoramento genético dos animais, reduzindo os riscos de prejuízos a atividade reprodutiva.

The article presents the European models of family policy divided into 5 models - the Scandinavian model, southern European model, conservative, liberal and post-socialist. In each of these the characteristics of policy for families are presented and divided into: axiological conditions, demographic, institutional family support, legal and family policy instruments. An overview of the various issues in the field of family policy is so important that the implementation of the effective family policy contributes to increased fertility, and thus of human capital, social and creative of the country. The article concludes with a summary and recommendations by individual models.

Lactating Holstein cows (n=1,456) were randomized in a 2×2 factorial design to compare the main effects of day of initiation of resynchronization after artificial insemination (AI; 32 vs. 39 d) and presynchronization with GnRH 7d before initiation of resynchronization on fertility to timed AI (TAI). This design resulted in the following 4 resynchronization treatments: (1) resynchronization (GnRH treatment, PGF2α treatment 7d later, GnRH treatment 56 h later, and TAI 16 h later), initiated 32 ± 3 d after AI; (2) presynchronization with 100 µg of GnRH 25 ± 3 d after AI and resynchronization initiated 32 ± 3 d after AI at nonpregnancy diagnosis; (3) resynchronization initiated 39 ± 3 d after AI (GPG39); and (4) presynchronization with 100 µg of GnRH 32 ± 3 d after AI at nonpregnancy diagnosis and resynchronization initiated 39 ± 3 d after AI. Overall, 344 cows were inseminated at estrus between enrollment (25 ± 3 d after AI) and TAI of the resynchronization treatments, and 1,112 cows received TAI. Progesterone (P4) was analyzed in blood samples collected from all cows at the first GnRH injection of the resynchronization protocols (G1), and ovarian structures were evaluated and blood samples were collected at G1, at the PGF2α injection, and at the TAI of the resynchronization protocols in a subgroup of cows (n=417). When analyzed as main effects, cows presynchronized with GnRH had more pregnancies per AI (P/AI) than nonpresynchronized cows (38.9 vs. 33.8%), whereas timing of initiation of resynchronization did not affect P/AI. Although cows with high P4 at G1 had greater P/AI than cows with low P4 (38.7 vs. 31.8%), presynchronization with GnRH did not increase the proportion of cows with high P4 (>1.0 ng/mL) at G1 but moved cows from a low-P4 environment to an intermediate-P4 level. Presynchronization with GnRH also decreased the percentage of cows with low P4 at the PGF2α injection, thereby increasing synchrony to the protocol. Cows with high P4 at G1 had a decreased ovulatory response to G1 compared with cows with low P4 (40.9 vs. 69.1%), and cows that ovulated to G1 had decreased luteal regression after PGF2α compared with cows that did not ovulate (78.5 vs. 87.3%). We conclude that presynchronization with GnRH 7d before initiation of resynchronization increased fertility in dairy cows, whereas timing of initiation of resynchronization did not.

This summary is a project of the Institute for Community Engaged Scholarship (ICES) at the University of Guelph, with project partners: the Business Development Office (BDO), SPARK Program at the University of Guelph, and Knowledge Mobilization Unit at York University. This project is part of the Pan-Canadian Research Impact Network. http://csahs.uoguelph.ca/pps/Clear_Research Boar sperm collected for artificial insemination may be damaged by short-term storage. However, dietary flaxseed appears to be a simple and effective way to improve the motility and viability of both fresh and stored boar sperm. Dietary flaxseed is a plant-based source of omega-3 polyunsaturated fatty acids, which are essential nutrients for improving boar sperm health. Project support by Agri-Food and Rural Link, Mobilizing Agri-food and Rural Research Knowledge. A program of the OMAFRA-U of G Partnership. http://www.uoguelph.ca/research/omafra/partnership/KTT_and_IP.shtml

BACKGROUND: The Australian baby bonus maternity payment introduced in 2004 has been reported to have successfully increased fertility rates in Australia. We aimed to investigate the influence of the baby bonus on maternal demographics and birth characteristics in Western Australia (WA). METHODS AND FINDINGS: This study included 200,659 birth admissions from WA during 2001-2008, identified from administrative birth and hospital data-systems held by the WA Department of Health. We estimated average quarterly birth rates after the baby bonus introduction and compared them with expected rates had the policy not occurred. Rate and percentage differences (including 95% confidence intervals) were estimated separately by maternal demographics and birth characteristics. WA birth rates increased by 12.8% following the baby bonus implementation with the greatest increase being in mothers aged 20-24 years (26.3%, 95%CI = 22.0,30.6), mothers having their third (1.6%, 95%CI = 0.9,2.4) or fourth child (2.2%, 95%CI = 2.1,2.4), mothers living in outer regional and remote areas (32.4%, 95%CI = 30.2,34.6), mothers giving birth as public patients (1.5%, 95%CI = 1.3,1.8), and mothers giving birth in public hospitals (3.5%, 95%CI = 2.6,4.5). Interestingly, births to private patients (-4.3%, 95%CI = -4.8,-3.7) and births in private hospitals (-6.3%, 95%CI = -6.8,-5.8) decreased following the policy implementation. CONCLUSIONS: The introduction of the baby bonus maternity payment may have served as an incentive for women in their early twenties and mothers having their third or fourth child and may have contributed to the ongoing pressure and staff shortages in Australian public hospitals, particularly those in outer regional and remote areas.

Do transitory economic shocks affect neonatal outcomes? I show that an unexpected, month-long blackout in Tanzania caused a sharp but temporary drop in work hours and earnings for workers in electricity-dependent jobs. Using records from a maternity ward, I document a reduction in birth weights for children exposed in utero to the blackout, and an increase in the probability of low birth weight. The reduction is correlated with measures of maternal exposure to the blackout. The blackout also increased fertility for teenage and first-time mothers, but selection into pregnancy cannot fully explain the drop in weights.

The thesis deals with the phenomenon of increased fertility and natality which became reality in the early 1970s. Explanation of the special terms used in the introductory part of the thesis is followed by description of historical process preceding phenomenon mentioned above. The part of analysis presents increased fertility and natality via various demographic indexes mainly in the form of graphs. Following part is focused on consequences caused by a strong generation during their lifetime. Commentary on the projection into the future relating to this generation is given in the conclusion.

The effects of an increase in photoperiod from 8 to 10 h at 18 wk of age on broiler-breeder performance was examined in two experiments. A control group received an 8 h photoperiod at 20 wk of age in each experiment. The rearing photoperiod of 8 h was supplied by a mixture of daylight and supplemental incandescent light in Experiment 1 and by incandescent light only in Experiment 2. Males and females were treated alike. The birds received a 14 to 16 h photoperiod supplied by a mixture of daylight and incandescent light after 20 wk of age. An increased photoperiod of 10h from 18 to 20 wk of age significantly increased fertility on a cumulative basis in both experiments when compared with the 8-h control group. The effect was more pronounced in Experiment 2 where incandescent light was used for rearing. Additionally, male livability was significantly better for the increased photoperiod (10 h) group in Experiment 2. No other significant effects were evident. Broiler-breeder males may be photostimulated to mature and exhibit increased fertility without adversely affecting female reproductive performance when grown in the same light environment as the females. This is possible because the broiler-breeder male appears to possess a lower threshold for photostimulation when compared with the female. These data provide a management system to improve broiler-breeder fertility.

En la presente investigación se evaluó el efecto en la motilidad y fertilidad espermática de trucha arcoiris (Oncorhynchus mykiss) de una solución salina 0,98% de NaCl enriquecida con 2,5; 5,0; 10,0 y 20,0mM de cafeína, utilizando como control una solución salina sin cafeína. Al utilizar cafeína en concentraciones de 10mM en la solución activadora se duplicó la duración de la motilidad espermática (165,0 ± 18,8s) con respecto al control (80,0 ± 12,5s). Se registró un aumento de la fertilidad al utilizar cafeína en el activador, aunque los valores no fueron estadísticamente significativos con respecto al control (81,6 ± 5,7%). Estos antecedentes demuestran la capacidad de la cafeína de prolongar la motilidad espermática en trucha arcoiris, aún cuando se debe continuar con nuevos ensayos que permitan determinar las dosis mínimas de cafeína requeridas para ser utilizadas en sistemas de producción masivos.

Koyuncu, M., Kara Uzun, S., Ozis, S. and Yerlikaya, H. 2006. Effects of selenium-vitamin E or progestagen- PMSG injections on reproductive performance of ewes. J. Appl. Anim. Res., 29: 137–140. The experiment was conducted on 120 Karacabey Merino ewes divided into four groups. Two groups consisted of 2-year-old ewes, before their first lambing and two groups of the 3-year-old ewes after the first lambing. Within each age category, one group of ewes was treated with 5 ml 0.1% sodium selenate and 250 mg vitamin E, the other group progestagen sponge + 500 IU PMSG. The progestagen sponge + PMSG treated groups demonstrated oestrus symptoms earlier than the Vit E + Se injected groups. The progestagen sponge + PMSG treated group significantly increased fertility (100%, P

The impact of acetyl salicylic add (ASA) on reproductive performance during periods of heat stress was studied in Japanese quail (Coturnix coturnix japonica). During a season when daily high temperatures averaged between 34 and 40 degrees C, four treatments each containing four replicates of five males and five females were given 0, 0.5, 1.0, or 1.5 g/L ASA in drinking water from 34 to 45 wk of age. At 39 wk of age control quail were lighter than quail fed ASA. Quail receiving 1.5 g/L ASA exhibited increased fertility, hatchability, and egg production and decreased late dead and total embryonic mortality. Early dead embryos, pips, chick weight, and egg weight were not different among treatments. The lumen of uterovaginal junction sperm host glands (UVJSHG) from control quail was apparently devoid of spermatozoa, whereas quail receiving 1.5 g/L ASA had the greatest apparent accumulation of spermatozoa. Control caudal infundibulum host glands (CPOI) were devoid of spermatozoa in contrast with CPOI from quail receiving ASA. Results show that UVJSHG lumens from quail receiving 1.5 g/L ASA had larger inside diameters than other treatment groups. However, the CPOI inside diameter and the outside diameters of both UVJSHG and CPOI were not affected by ASA. Adding 1.5 g/L ASA to the drinking water of quail under heat stress improved body weight, fertility, hatchability, embryonic mortality, egg production, egg specific gravity, and sperm storage capacity.

Fertility in human populations is influenced by a variety of factors. The challenge of approximating the relative importance among them long eluded scientists. Davis and Blake (1956) brought about a critical advancement by creating a conceptual analytical framework which distinguished ‘intermediate’ in contrast to social, economic, behavioral, and other fertility determinants. The societal factors affecting fertility can operate only indirectly through the intermediate or proximate determinants, which directly modify fertility by affecting conception, gestation, and successful parturition. Two decades later Bongaarts (1978) devised a comprehensive quantitative model to analyze fertility changes caused by variations in the direct/intermediate/proximate determinants. Four main proximate determinants account for about 96 percent of fertility variations: the proportion of women's reproductive life spent in stable sexual unions, the use of contraception, the practice of induced abortion, and lactational infecundability correlated to the duration of breast-feeding. Long periods of breast-feeding in traditional societies result in women bearing 5–8 rather than the biological maximum of 13–17 children. During the demographic transition breast-feeding is reduced, however, the potential for increased fertility is more than offset by spending less time in sexual unions, by the increase in the use of contraception and frequently induced abortion played an important role in modifying fertility.

[EN] During 6 months, 1552 artificial inseminations (Al) were carried out to compare three different techniques to induce oestrous in rabbit females. The first method consisted of transferring the female and its litter if any to another cage 2 days before Al (biostimulated group), the other two were based on hormonal treatments: does were either treated with 20 IU PMSG 72 hours before Al ora combination of 16 IU PMSG and 8 IU hCG (0.2 mi i.m.) injected 48 hours before Al. A control group of does was not treated. Results showed that the different treatments and the physiological status of females statistically influenced fertility and the number of born alive, but not the number of stillborn, mortality and weight of young 2 days post parturition. PMSG and the PMSG + hCG resulted in a significant (P, [FR] Afín de comparar 3 techniques différentes d'induction de l'oestrus chez la lapine, 1552 inséminations artificielles ont été effectuées pendant 6 moís. La premiare méthode consiste a transférer la lapine dans une autre cage deux jours avant l'insémination artificielle (groupe biostimulé), les deux autres comportent des traitements hormonaux: les lapines ont re~u soit 20 U./. de PMSG 72 heures avant /'/.A., soit une combinaison de 16 U./. de PMSG plus 8 U./. d'hCG (0,2 mi i.m.) en injection 48 heures avant /'/.A.. Les lapines du groupe témoin n'ont r~u aucun traitement. Les résultats montrent que les différents traitements et le statut physiologique des feme/les influencent signíficatlvement la fertflité et le nombre de lapereaux nés vivants mais pas le nombre de lapereaux mort-nés, ni la mortalité, ni le poids des lapereaux a l'age de 2 jours. Compsrés au groupe témoin, les traitements PMSG et PMSG + hCG augmentent significativement (P

A monoclonal antibody (M1) was produced against seminal fluid heparin-binding proteins (HBP) from a vasectomized bull. In the first part of this study, the presence of HBP in sperm or seminal fluid was determined for 53 bulls with an ELISA using M1. Bulls (8 to 18 per pasture) were bred to 1,114 cows at ratios of 1 bull :25 cows. Bulls with detectable HBP on sperm membranes were 11 percentage points more fertile than bulls with undetectable HBP in sperm membranes. In the second part of this study, three sperm membrane HBP approximately 30, 24, and 21.5 kDa were identified with Western blots using M1. Santa Gertrudis bulls (n = 64) were bred to 1,354 Santa Gertrudis cows in groups with 2 to 11 bulls. Bulls with those three HBP (Group A) or a single 30-kDa HBP (Group B) in sperm membranes had the greatest fertility, ranging from 74.4 to 89.9% (mean = 81.5%) of the palpated cows that were pregnant. Bulls with the 21.5- and 30-kDa HBP (i.e., the 24-kDa HBP was absent ; Group C) had a reduced fertility of 61.3%. Bulls without detectable HBP (Group D) resulted in 41.9% of 186 cows palpated pregnant. Bulls in Groups A and B were more (P

Using a family reconstitution study the biology of the plague in Penrith, Cumbria in 1597/8 is described in detail; it was an explosive epidemic that spread rapidly within families and 606 individuals died of the plague, some 40% of the population. The age-specific mortality corresponded with the calculated age structure of the population and infection appeared to be random. The sex ratio of victims was 1.37 females to 1 male. The plague spread from the northeast via Richmond and then exploded in the Eden valley, appearing almost simultaneously in Penrith, Kendal and Carlisle. The details of the epidemics and the location and the climate of these widely separated small market towns show that bubonic plague was not the causative agent, and the possibility that anthrax was responsible for the drastic mortality is briefly considered. The population rapidly built up after the plague, largely by immigration and not by increased fertility, and steady-state conditions were re-established within 5 years and continued for 150 years. This severe mortality crisis of the plague had a profound effect on the population at Penrith, triggering long wavelength oscillations in both baptisms and burials in this population living under marginal conditions and maintained in steady-state by density-dependent factors.

The article looks at the results of a study by cancer biologist Susab Erdman, evolutionary geneticist Eric Alm, and team on the effects of probiotic yogurt on obesity in mice that found that male mouse subjects exhibited more masculine behaviors and increased fertility.

Objetivos: Determinar si la administración por vía oral del extracto etanólico de las hojas de Mimosa pudica (mimosa) modifica la fertilidad en ratas normales. Diseño: Estudio experimental. Institución: Instituto de Investigaciones Clínicas, Facultad de Medicina, Facultad de Farmacia, Universidad Nacional Mayor de San Marcos y Hospital Nacional Hipólito Unanue, Lima, Perú. Material biológico: Ratas albinas, y hojas de Mimosa pudica. Métodos: Cuarentiocho animales fueron divididos aleatoriamente en grupos de seis animales cada uno. El primero fue control, con solución de suero fisiológico 5 mL/kg, y los siguientes recibieron extracto vía oral 50, 250 y 500 mg/kg, durante 21 días. Cada grupo consideró 6 hembras y 6 machos juntos. Los animales fueron sacrificados para observar la presencia de fetos en el útero. A las hembras se les extrajo muestra de sangre, para conocer el nivel de FSH, estradiol y progesterona, expresándose en µg/dL. El dosaje hormonal se realizó por el método de electroquimioluminiscencia. En el estudio de antiimplantación se usó 2 grupos de 5 ratas hembras grávidas; un grupo recibió agua y el otro recibió el extracto de la planta, en dosis de 600 mg/ kg, durante 10 días. Principales medidas de resultados: Disminución del número de fetos y niveles hormonales. Resultados: Los flavonoides, compuestos fenólicos y taninos estuvieron en mayor cantidad en el extracto etanólico. Las ratas que recibieron 250 mg/kg presentaron mayor número de fetos, seguidas por las de 50 mg/kg; en tanto que con la dosis de 500 mg/kg disminuyó el número de fetos comparativamente con las ratas que no recibieron la planta; hubo incremento de FSH y de progesterona. Conclusiones: En condiciones experimentales se muestra que en dosis de hasta 250 mg/kg aumenta la fertilidad, pero a 500 mg se reduce la fertilidad en ratas normales. Objectives: To determine whether oral administration of Mimosa pudica (mimosa) leaves ethanol extract modifies fertility in normal rats. Design: Experimental study. Setting: Instituto de Investigaciones Clinicas, Facultad de Medicina, Facultad de Farmacia, Universidad Nacional Mayor de San Marcos, Hospital Nacional Hipolito Unanue, Lima, Peru. Biological material: Albino rats and Mimosa pudica leaves. Methods: Forty-eight animals were divided randomly into groups of six animals each. The first was control and received saline solution 5 mL/kg and the others 50, 250 and 500 mg/kg oral extracts for 28 days. Each group considered 6 males and 6 females together. The animals were killed to observe the presence of fetuses in uterus. FSH, estradiol and progesterone levels were determined in µg /dL in female rats’ blood samples and hormone dosage was done by electrochemoluminiscence method. In the antiimplantation study 2 groups of 5 pregnant female rats were used; one group received water and the other 600 mg/kg plant extract doses for 10 days. Main outcome measures: Reduction in the number of fetuses and hormone levels. Results: Flavonoids, phenolics and tannins were in larger quantity in the ethanol extract. Rats that received 250 mg/kg showed a greater number of fetuses followed by 50 mg/kg, while 500 mg/kg dose decreased the number of fetuses as compared with rats not given the plant; FSH and progesterone showed increased levels. Conclusions: In experimental conditions Mimosa pudica’s 250 mg/kg doses increased fertility but 500 mg reduced fertility in normal rats.

Four feeding regimens were compared for the pullet-layer transition period and two light types, white and narrow-band green fluorescent, were compared in the grower period to determine their subsequent effects on reproductive performance of broiler breeder hens. Four limit-feeding treatments imposed from 18 wk (body weight of 1.8 kg) to “mature weight” of 2.8 kg at 27 (Treatment 1), 25 (Treatment 2), 24 (Treatment 3) and 22.5 (Treatment 4) wk of age supported weight gains of, respectively, 15, 19, 23, and 27 g per day. Production of total and hatching eggs was similar among all dietary and lighting treatments. Hens given dietary Treatment 1 had a higher production from 224 to 252 days but had a lower production from 168 to 189 days associated with a 2.6-day later age at 50% egg production. Feeding regimen and lighting treatment had no effect on egg weight, and feeding did not affect mortality. Green lighting reduced mortality from 2.0 to 1.4% at 70 to 126 days and from 5.7 to 4.0% from 126 to 280 days of age, compared with white lighting. Fertility was 5% lower for Treatment 4 versus Treatment 1 and 4% lower for white versus green lighting. The advantage of higher initial hatching egg production obtained with rapid growth, of >15 g per day, during the transition period was outweighed by detrimental effects on production and fertility in later periods. Green light may increase chick production per hen housed by causing decreased pullet mortality and increased fertility.

1that folic acid diminishes the rate of birth defects by selectively inducing abortions (terathanasia) seem slim. A more appealing explanation for an increase in spontaneous abortion, if it does occur, is that adequate maternal periconceptional folic acid intake maintains pregnancies that would otherwise abort so early as to not even be recognised as pregnancies. This hypothesis fits with the additional observation noted by Hook and Czeizel of increased fertility among women on folic acid supplements (ie, previously unrecognised pregnancies are retained long enough to be counted even though they go on to spontaneously abort). This explanation also suggests adequate folic acid intake allows maternal-conceptus interactions to function more normally. Supplying adequate folic acid by diet, supplementation, or fortification is not interference.

THERE is considerable controversy about what females gain from mate choice in a lekking species in which males provide no obvious resources. Females may gain direct benefits such as safe copula-tions or increased fertility by mating with particular males, or they may gain indirect benefits for their offspring1–3. It is difficult to look for paternal effects on offspring performance because it is hard to control for any differences in the material and genetic contribution provided by the female and in the environment of the offspring during development; previous experiments have con-trolled for rearing environment but not maternal effects4. Here I report results from a controlled breeding experiment, with females allocated to males at random and all offspring reared under the same conditions, which show that the offspring of successful lek peacocks (Pavo cristatus) with the most elaborate trains grow and survive better under nearly natural conditions.

In order to increase variability in the octopioid tritordeum a new octoploid tritordeum has been synthesized after colchicine doubling of the chromosomes of the Hordeum chilense × Triticum aestivum ssp. sphaerococcum hybrid. The amphiploid showed full pairing in 30 % of the pollen mother cells, The fertility was higher than in previous tritordeums (1.65 grains per spikelet and 43.00 grains per spike). Hybrids between the octoploid tritorceums were sterile. However, hexaploid × octopiold trhordeum hybrids were fertile and secondary tritordeums were extracted with increased fertility.

The relationship of feeding time to egg production, egg weight, egg shell quality, fertility, and hatchability was examined in two trials. Slow and fast-feathering strain Hubbard females were used in Trial 1 and slow-feathering strain Arbor Acres females were used in Trial 2. Feeding times of 0800 or 1300 h throughout the laying periods were compared. Slow feathering females in Trial 1 exhibited significantly increased egg weight and significantly decreased percentage shell when compared with fast-feathering females. Feeding at 1300 h increased significantly egg specific gravity, egg shell weight, and percentage shell in Trials 1 and 2. Significant interactions of feeding time and strain occurred in Trial 1 with respect to fertility and hatch of all eggs set. Feeding at 1300 h increased fertility and hatch of all eggs set in fast-feathering hens but the opposite occurred in slow-feathering hens in Trials 1 and 2. Within slow-feathering hens, hatch of fertile eggs was decreased by 1.7% (Trial 1) and 1.5% (Trial 2). The results show that afternoon feeding that provides calcium intake near the time of egg shell calcification decreased significantly hatchability in eggs from two slow-feathering strains of females but not in eggs from a fast-feathering strain. These results suggest that altering time of feed intake can decrease hatchability.

The age at which women married in the eighteenth century has come to occupy a central role in current historical debate. It is an issue of crucial importance to those demographers who argue that the main cause of the rise in population of the eighteenth century was increased fertility the consequence of earlier marriage extending the years of greatest fertility in women, and changes in the proportion of women remaining celibate. In particular, it has been argued by some that it was the expansion of domestic industry, cutting across the traditional and largely inelastic demand for labour, which led to the breakdown of the restraints on early marriage. This is a thesis that links up two current areas of historical debate that on the causes of the eighteenth century increase in population, and that opened up by the 'Proto-industrialists'. The debate continues. Surprisingly by no means all of it focuses sharply if at all on women, although where fertility is concerned women can hardly be ignored. This article sets out to ask just how firm are the conclusions reached on the mean age of women at marriage and its relation to fertility. It critically examines the basis for the demographers' statistics, and poses the question of how far this focusing on the mean age at marriage conceals more than it reveals about marriage patterns. It looks at the arguments of those who, while in agreement that a fall in the mean age at marriage occurred, fail to agree on what caused it or on how variations in the age at which men and women married can be explained. How valid is the link claimed by some historians between the declining age of marriage of women and protoindustrialisation? Does marriage age relate to real wages, and if it does, to whose real wages the man's, the woman's, or those of both? In recent work on marriage patterns in the eighteenth and nineteenth centuries, several factors other than real wages have been found to influence age of marriage not least changing attitudes to marriage and what marriage involved, to pre-marital pregnancy and illegitimacy. Such factors have been found to vary between communities and to be in turn

The generally held view that increased self-fertilization should be advantageous in the absence of counteracting selective forces reducing viability or fertility is reexamined. It is pointed out that the models on which this view is based all imply a gain in male (pollen) fertility with increased selfing. Hence, the postulated advantage may equally well be due to increased fertility, a fact which reopens the discussion on the selective significance of differential selfing. A new model for differential self-fertilization is presented which avoids built-in fertility selection by explicitly considering pollen available for self- and for cross-pollination. Plant types are distinguished with respect to their amounts ri of pollen available for self-pollination, and these types are assumed to be identical with respect to their pollen and ovule fertilities. Moreover, the efficiency of cross-pollination is allowed to depend, for example, on population density, thus giving rise to a parameter b called “crossing potential”, while the efficiency of self-pollination is described by a parameter a called “selfing potential”. These parameters may be conceived of as ecological parameters. Increasing ri produces a simultaneous increase in each of the four measures of self-fertilization (introduced in Part I of the present series) irrespective of the values of the ecological parameters. It is then shown that increased selfing can be both advantageous and disadvantageous in terms of fitness, dependig on the ecological parameters as well as on the mode of self-fertilization (i.e. where selfing occurs before or after outcrossing). The main result is, roughly, that for both selfing modes high crossing and low selfing potential favour increased cross-fertilization, while the reverse favours increased self-fertilization. However, the regions for a and b in which this holds true differ substantially for the two selfing modes. In the complements of these regions strange conditions for the evolution of increased selfing or outcrossing, respectively, exist. The significance of these results for explaining experimental observations is discussed.

Allopolyploids were raised by oolchicine treatment of vegetative buds in the triploid hybrid of tetraploidPhaseolus species xP. calcaratus cross. They had 70 per cent pollen fertility and produced many viable seeds. The average chromosome configuration per cell at MI in them was 1.56IV + 0.01m + 29.30II + l.llr. It has been concluded that the increased fertility in allopolyploids was due to more regular meiosis and the low frequency of quadrivalents indicated the occurrence of preferential pairing.

Supplementation of the diets of pregnant and nursing mothers in underdeveloped countries is sometimes criticized because more food for these women is seen as producing more body fat, shortened postpartum amenorrhea, and increased fertility. We argue that the link between body fat and shortened postpartum amenorrhea is based on a hypothesis that has not been corroborated. The critical-fat hypothesis is that menarche, maintenance of menstrual cycles, and the delay of menstruation after pregnancy are all determined by "critical" (causal) fat levels. Data refute the menarche-fat link outright. Evidence for the link between menstrual-cycle maintenance and fat is clouded by outside variables such as physical or emotional stress. Of special importance to postpartum amenorrhea is type and duration of lactation, with frequent, on-demand nursing of an unsupplemented infant being associated with longer amenorrhea. The nutrition-fat-fertility link, therefore, is uncorroborated and may be on the way to refutation. Con...

Increased fertility of heterozygotes with respect to decreased foetal loss among offspring of heterozygotes has been proposed by several authors as a possible explanation for the high gene frequency of CF, TSD and PKU in certain populations. Studies comparing reproductive outcome of heterozygotes with reproductive performance in the general population or in special control groups have been done on several occasions. These studies, however, are known to be heavily biased, on the one side by the fact that ascertainment of heterozygotes through affected offspinrg will tend to underestimate the relative frequency of smaller families, and on the other side because of the inadequacy of census data for comparison and the biases inherent in selection of control families. Careful analysis of the biases involved provides suggestions for proper corrections. From this a method has been developed which offers a better approach to the study of heterozygote fertility in those autosomal recessive conditions which lack a test for direct heterozygote detection.

It has been hypothesized that bighorn sheep living in unpredictable desert environments may resort to a life history pattern of reproductive gambling in which they have increased fertility because of continuous breeding. To determine whether such gambling is in fact feasible, simulations of a seasonal and gambling population were run with survival schedules generated as functions of precipitation. Although annual per capita fertility was substantially increased in the gambling population, the seasonal strategy resulted in a higher finite rate of increase. These results indicate that reproductive gambling, as modeled, is not an ecologically stable strategy unless survival of offspring born outside the optimum period is substantially increased.

Synchronization of estrus and fertility were determined in a series of 8 trials. Various levels of chlormadinone acetate (CAP) were fed for either 7 or 9 days. An injection of 5 mg of estradiol valerate and CAP was given at the start of the feeding period. In some trials estradiol 17β was injected near the end of the feeding period. In trial 1, 98% of the CAP-treated heifers were in estrus in a 5-day period, but only 46% conceived at first service compared to 80% in the non-synchronized heifers (P In trials 2 through 6, 0.25 mg estradiol 17β injected either 60 or 72 hours after the last CAP feeding reduced the interval to ovulation in heifers that ovulated. However, use of estradiol 17β reduced the number of heifers ovulating in most trials. In trials 7 and 8, estrus was effectively synchronized with either 7- or 9-day feeding of 7.5 or 10 mg of CAP daily followed by .5 mg estradiol 17β, 72 hours after the last CAP feeding. Pregnancy rates at first service varied from 21 to 45% in heifers in the synchronized groups, compared to 58% in the controls in trial 7 (P In this series of trials, fertility was reduced from 24 to 43% with the use of CAP and estradiol valerate. Conception rates at first service were not improved by varying the length of feeding (7 or 9 days), level of CAP (7.5 or 10 mg) or by attempting to reduce the variation in ovulation time with estradiol 17β. None of the combinations of these three drugs used increased fertility in these trials.

1. Fowl and turkey spermatozoa were found to utilise oxygen when stored in tubes at 5 and 10 degrees C respectively; the storage medium becoming rapidly anaerobic. 2. This aerobic metabolism was encouraged by continuous introduction of air into the semen during storage. 3. Fertility of turkey semen stored at 10 degrees C for 24 h in diluent containing glucose was increased 2.4-fold by simple aeration and reached 99% of that achieved with fresh semen. 4. Fertilities of greater than 90% were also achieved with fowl semen stored for 48 h at 5 degrees C in a diluent with or without glucose. The increased fertility on aeration was greater (2.2-fold) with fowl semen stored in the absence of glucose.

The decrease in the frequency of twin births depends solely on the decrease of dizygotic twins (ZZ). Examination of birth registration forms in Baden-Wurtemberg from 1955 to 1972 showed that the decrease of ZZ births is only partially due to changes in maternal age and parity. On the other hand one can assume that the proportion of women with genetically determined increased fertility, to whom ZZ mothers largely belong, is reduced among mothers due to widespread contraceptive practice so that ZZ births are also rarer. In addition, the possibility that ovulation inhibitors may have a negative influence on the numbers of double ovulations must also be considered.

Oestrus was synchronised in 88 goats using progestagen-impregnated intravaginal sponges (60 mg Repromap; Upjohn) left in place for 17 days, followed by intramuscular injection of PMSG (300 i.u.) at sponge withdrawal. The percentages of does that came into oestrus in 0–24, 25–48, 49–72 and 73–96 h periods were 42, 30.5, 10.5 and 6.5 (cumulative 89.5%). The time of onset of oestrus ranged from 16 to 40 h. Breeding at the synchronised oestrus using intact bucks (24–96 h) or artificial insemination with frozen-thawed semen, at fixed times of 24, 48, 72 and 96 h, resulted in 71% and 81% conceptions respectively. Intrauterine deposition of semen was possible in 31.3%, 62.5%, 87.5% and 6.3% of cases at 24, 48, 72 and 96 h respectively. Twinning percentages were 54.5% and 56% for natural mating and artificial insemination. Kidding was spread over a 14-day period with mean gestation lengths of 149 days for singletons and 147 days for twins. The results indicate that use of progestagen-impregnated sponges with PMSG is an efficient method of synchronisation of oestrus and may result in increased fertility in goats and, if used with A.I. with frozen semen, may contribute to increased breeding efficiency and rate of genetic improvement of goats in Asia.

ARTIFICIAL insemination of poultry has been used quite successfully for the more economical use of sires, especially in progeny test breeding, and for using a particular male which is otherwise incapable of normal mating, according to Warren and Gish (1942). Bonadonna (1939) suggested the use of artificial insemination for fertilizing the eggs of hens confined to batteries. Burrows and Quinn (1938) showed that it was possible to obtain percentages of fertility by the use of artificial insemination as high as could be obtained through natural matings. Burrows and Marsden (1938) increased fertility from an old tom turkey by the use of artificial insemination. Results obtained by Bonnier and Trulsson (1939) showed that 30 percent semen diluted in Ringer solution gave better results than undiluted semen, on the average. Burrows and Quinn (1939) reported that semen in storage at 4.4° C. lost its fertilizing ability in two hours, when stored at . . .

Some aspects of growth are reported for x-rayed populations of wild-type flour beetles cultured as single- or mixed-species. Irradiation with 250-kv x rays was carried out at 1 kr/min to total doses of 2, 4, or 6 kr. Reproductive abilities, measured as the mean number of F/sub 1/ adults per female, for single- species populations of T. castaneum given 2 hr approached control values after one month, whereas those of T. confusum persisted below controls. Four kr was almost sterilizing, over 90 and 99% sterilizing respectively for T. castaneum and T. confusum, while 6-kr doses induced complete sterility in both species. Dominant lethals induced by 2 kr were approximately twice as abundant in T. confusum as in T. castrneum. Increased fertility with time was considered evidence that undifferentiated gametes were more radioresistant than mature ones. Selective elimination of a flur beetle species (T. confusum) in coexistence was indicated at exposures greater than 4 kr of x rays but less than 6 kr. Interspecies antagonism and 2-kr irradiation, as an environmental stress factor, appeared additive in adversely influencing the reproductive ability of T. confusum. The dose-response curves for reproduction were linear up to 4 kr except for T. confusum. After 4more » kr the dose-response curves departed from linearity for both species. Biomass (standard dry wt) of F/sub 1/ adults decreased with increasing dose; however, the weight of individuals was not altered. Parental mortality was not affected at 2 and 4 kr; 94 to 100% were alive at 10 weeks. In the 6-kr group, 75 and 58% of T. confusum were alive in the single- and mixed-species populations, respectively, indicating that irradiation and coexistence reduced survival. Thus, these 2 organisms of similar biology differed radiologically, as seen by the overall greater radioresistance of T. castaneum compared with that of T. confusum. The one more pair of chromosomes in T. castaneum probably does not satisfy a genetic interpretation of radioinduced damage, but physiologic and cytogenetic factors may be responsible. (BBB)« less

Unequal fertility of reciprocal crosses between certain bark beetles and increased fertility of the F1, with respect to the original cross, appear to result from nuclear-controlled cytoplasmic incompatibility. This mechanism, also implicated in instances of reciprocal mating sterility, may be an important factor in the reproductive isolation of closely related species.

Field experiments were conducted to study the effectiveness of 2,2-dichloropropionic acid (dalapon) for the control of 55 morphologically distinct ecotypes of johnsongrass (Sorghum halepense(L.) Pers.) collected throughout the United States and from several foreign countries. Ecotypes varied widely in their response to dalapon whether collected from Mississippi, from 10 other states, or from eight foreign countries. Initial control of seven ecotypes with dalapon increased 8 to 35% when nitrogen fertilization was increased from 0 to 300 lb/A. Regrowth of surviving plants was more vigorous with increased nitrogen levels so increased fertility reduced final control. Comparative differences in the susceptibility of the seven selected ecotypes to monosodium methanearsonate (MSMA) were not as great as those obtained with dalapon. Varying the rate of nitrogen fertilization had less effect on johnsongrass susceptibility to MSMA than to dalapon. Dalapon controlled sorghum almum (Sorghum almumParodi) better than johnsongrass.

ZAWADOWSKY (i) has reported that ground cocks' combs fed to young male rats produce smaller testes, seminal vesicles, and prostate glands than normal. He obtained the same result by the injection of alcohol extracts of comb tissue. Buckner, Insko,and Martin (2) have shown that comb re' moval in cockerels leads to larger testes and increased fertility. Zawadowsky confirmed the result of comb removal on testis sise. From these and similar experiments Zawadowsky postulates a reciprocal relationship between sec' ondary sex characters such as the comb and the gonads, in this case, the testis. According to this suggestion, not only does the testis stimulate the comb, the accepted relationship, but the comb in turn inhibits the growth of the testis and in this waycontrols its output of male hormone. Such a regulatory me chanism would have many challenging aspects and would involve a re'consideration of accepted mechanisms of sexualphysiology.

An experiment was conducted with chickens to investigate the relationship between the volume of a single insemination of undiluted semen and fertility and hatchability. The fifteen doses of semen ranged from 0\m=.\0002to 0\m=.\15ml. Semen samples were collected with a minimum amount of cloacal fluid dilution and pooled within strain. Twelve White Leghorn hens were inseminated with each of the fifteen doses of semen from each of three strains of males. Although some fertility resulted from the smallest dose, most of the hens were infertile. Only when doses 0\m=.\004ml and larger were used did nearly all hens lay some fertile eggs. There were highly significant differences among strains and doses in the duration of fertility observed. From forty to seventy million spermatozoa per insemination were required for high fertility. Doses larger than this (0\m=.\006to 0\m=.\01ml) increased fertility very slightly but the difference was not significant. The number of 'skipped infertile eggs' per bird (defined as the number of infertile eggs laid between the 2nd day after insemination, and the day the last fertile egg was laid) decreased gradually as the

Nitrogen has proved effective in protecting puparia of Ceratitis capitata (Wiedemann) from gamma-irradiation induced damage as evidenced by increased adult emergence from early irradiated puparia, adult male survival, and male fertility. Chilling to 4° during irradiation had the opposite effect and it is concluded that the extent of damage which can be altered by these treatments is due to oxygen-dependent effects of irradiation. Increased fertility after irradiation in nitrogen may be due to increased sexual vigour rather than to reduction in damage of genetic material but this has not been proved. Effects on percentage adult emergence, survival and fertility are probably manifestations of the same phenomenon of irradiation-induced lethargy. It is considered that the effect of treatment with nitrogen at 25° or chilling to 4° in air during irradiation may be of value in increasing the flexibility of a large-scale campaign to control C. capitata by the sterile-insect release method. Adults from puparia of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), subjected to sterilizing doses of gamma radiation, survive best when treated late in puparial life (Arroyo et al. 1965). This fact greatly affects the logistics of any large-scale sterilization programme (Knipling 1960) for the control of this or other insects in the field (see Smith 1963). Hence we have tried to separate the genetic and somatic effects of gammairradiation upon puparia of C. capitata. We hoped that if somatic effects could be lessened without affecting the degree of sterility induced by a given dose, the age-range of puparia which could be successfully sterilized might be increased, thus allowing greater flexibility in the development of a control programme. The lessening of radiation-induced damage under conditions of low oxygen tension has been well established in both plant and animal tissues (Patt & Brues 1954; O'Brien & Wolfe 1964). Nitrogen increases the radiation resistance of the wasp Habrobracon during development (Clark & Herr 1955), and Baldwin and Salthouse (1959) showed that oxygen deficiency protected the bug Rhodnius from the dual effect of delayed moulting and burning of the epidermis following administration of X-rays. Present results involving irradiation of C. capitata puparia in nitrogen at 25° or in air at 4° show that some protection from lethal somatic effects is possible. Zusammenfassung γ-BESTRAHLUNG VON PUPPEN DER MITTELMEERFRUCHTFLIEGE (CERATITIS CAPITATA) IM HINBLICK AUF IHRE BEKAMPFUNG MIT DER “STERILE MALE”-TECHNIK. Es konnte gezeigt werden, dass bei der Bestrahlung der Puparien von Ceratitis capitata (Wiedemann) mit 10 k-rad Gammastrahlen in einer Stickstoffatmosphare der erreichte Prozentsatz schlupfender Imagines — im Vergleich mit der Bestrahlung in Luft bei 25° oder 4°C— vergrossert ist, wenn die Puparien am 4. Tag der Entwicklung bei 25°C behandelt werden. Die Schutzwirkung des Stickstoffs ist noch grosser bei einer Dosis von 30 k-rad. Nach Bestrahlung mit 10 k-rad in einem spateren Stadium der Puparien-Entwicklung blieb das Uberleben der geschlupften Mannchen von der Behandlung mit Stickstoff oder von der Abkuhlung unbeeinflusst. Jedoch ergaben am 4. Tag der Entwicklung behandelte Puparien nach Bestrahlung in Stickstoff langer lebende Mannchen und das Uberleben war nach Bestrahlung in Luft bei 4°C am geringsten. Diese Ergebnisse weisen auf die Existenz einer “sekundaren Letalwirkung” der Bestrahlung hin, die von Sauerstoff abhangig ist, da Stickstoff die Sauerstoff-spannung in den Geweben herabsetzt, wahrend Abkuhlung auf 4°C die Loslichkeit von Sauer-stoff in den Gewebeflussigkeiten erhoht. Der “primare Letaleffekt” der Bestrahlung ist der, welcher die Weiterentwicklung durch Schadigung der sich differenzierenden Gewebe verhindert. Der Sekundareffekt verhindert das Schlupfen der voll entwickelten pharaten Imago aus ihrem Puparium, und es wird angenommen, dass die auf Bestrahlung wahrend fruher Entwicklungsstadien folgende Einschrankung der Uberlebensfahigkeit der Erwachsenen — wie sie von anderen Untersuchern bei anderen Insekten gefunden wurde — eine Manifestation der gleichen Erscheinung darstellt. Es wird vermutet, dass diese sauerstoffabhangige sekundare Letalitat irgendwie mit einem Eingreifen in den normalen Atmungsstoffwechsel des Insekts zusammenhangt. Es wird im Vergleich mit der Bestrahlung in Luft bei 25°C eine Steigerung der Fertilitat der in Stickstoff bei 25°C bestrahlten Mannchen und eine Minderung der Fertilitat nach Bestrahlung in Luft bei 4°C festgestellt. Das konnte eher eine Folge von Veranderungen in der sexuellen Vitalitat als von Veranderungen in der Haufigkeit der Induktion dominanter Letalfaktoren in den Spermatozoen sein. Weitere Untersuchungen zur Bestimmung dieses Punktes sind notwendig. Es wird angenommen, dass die Wirkungen einer Behandlung mit Stickstoff oder Abkuhlung auf 4°C wahrend der Bestrahlung von Nutzen fur die Steigerung der Flexibilitat bei einer weitgespannten Bekampfungsaktion von C. capitata durch die S.I.R.M. sein durften.

It has been reported by several investigators that some incompatible flowers self-pollinated were rendered effective through a simple treatment on their stigmas. SEARS (1937) has shown that in the broccoli mutilated flowers selfed and kept in moist chamber set numerous seeds, but control flowers selfed produced no seed at all. Since there was no evidence that removal of more than a thin layer of stigmatic tissue further increased fertility, he concluded that the inhibitory reaction is limited to the surface stigmatic cells.As this paper attracted my attention, I tried a similar experiment to this with self-incompatible individuals of the Japanese radish. In this experiment the portion of stigmas removed was as follows; (1) none (control), (2) one-half stigma, and (3) stigma. Mutilated flowers were applied with their own pollen, and kept in moist chamber.The results obtained were fully in accord with those of SEARS (1937). Each case where stigmatic material was removed, was vastly superior in pod-setting and seed production to the control. The best result was obtaind in the case of one-half stigma.SEARS (1937) demonstrated that in the radish as well as in the broccoli, self-incompatibility is attributed to decreased germination of incompatible pollen and to no penetration of tubes into the stigma. The same pollen behavior as this has recently been corroborated in the Japanese radish (TATEBE 1938). In considering these results, it may be assumed that in the Japanese radish the inhibitory reaction is chiefly limited to the surface layers of the stigma at the flowering time, and that the removal of this region permits self-fertilization.

Progress in the knowledge of soil bacteriological investigations must necessarily depend upon an acquaintance with the individual factors that determine the efficiency of a particular group of soil organisms. Once the relative importance of these factors is determined, the unessential discriminated from those which are of paramount importance, a constructive policy for the promotion of bacterial activity may be announced that will be reflected in an increased fertility of agricultural lands. Investigations on the two general processes nitrogen fixation and nitrification, have been reported recently from these laboratories.2 These reports have announced the effects of various organic and inorganic fertilizers in developing certain bacterial floras; the stimulus exerted by cultivation on the two processes just mentioned has been noted; and the comparison of a number of soil types with reference to their bacterial activities was emphasized in the investigations. The results of this work were such as to suggest a number of interesting possibilities to account for unusual conditions that were here and there encountered. Accordingly, an effort has been made to detect some of the influences that are responsible for these conditions and to place certain factors in the relative positions of importance. The data in this paper, which are in every case somewhat preliminary are closely connected with those of the previous publication and are accumulative toward establishing certain contentions which have heretofore been suggested. The moisture content of a soil with relation to its free nitrogen fixing power is a matter which it would be well to investigate. The rather meager information on this subject has recently been aug

HUNT, Winter and Bethke (1939), studying the riboflavin requirement of the chicken, found that dehydrated alfalfa leaf meal added to the diet of hens in batteries increased the hatchability of fertile eggs to a greater extent than could be accounted for by the riboflavin content. Cravens et al. (1942), working with chickens maintained under practical confinement conditions, reported that alfalfa leaf meal increased hatchability but not fertility. Jacobs et al. (1953), reported that 5.0 percent dehydrated alfalfa leaf meal increased fertility and hatchability when added to the diets of hens in cages. The present experiment was undertaken to study the effect on fertility and hatchability of feeding dehydrated cereal grass and dehydrated alfalfa meals as supplements to a poultry diet composed of natural ingredients. The experimental diets were fed to chickens maintained under practical confinement conditions from time of hatching through a period of egg production. In order to study . . .

Selection over five generations increased the fertility (seed set) in a population of tetraploid Lolium perenne from 67.57 per cent in the second (C 2) to 73.95 per cent in the seventh (C 7) generation. The increased fertility is associated with a high quadrivalent frequency and a low frequency of bivalents, trivalents and univalents. The high quadrivalent frequency in the selected population was achieved partly by a slight overall increase in chiasma frequency but mainly by a redistribution of chiasmata.

Both male and female Argas persicus mated more than 10 times. Males irradiated at doses which induce 99% dominant lethals (12 KR) were fully competitive for the first 2–3 weeks after exposure, then became aspermic. Decreasing the irradiation dose to 3 KR increased fertility to about 30%, but aspermia occurred about the same time as in higher doses.

RESULTS of experiments reported by Moore and Byerly (1942), and Parker (1945) with artificially inseminated hens suggest that restricting the mating of chickens to the afternoon should increase fertility. Moore and Byerly showed that the percentage of fertile eggs laid following the artificial insemination of hens with a hard-shell egg in the uterus was lower than that obtained following the insemination of hens that had just laid or of hens that had a soft-shell egg in the oviduct. Their results indicate that, for highest fertility, hens should be inseminated at a time when fewest of them have hard-shell eggs in their oviducts. Hens artificially inseminated in the afternoon were found by Parker to have higher fertility and hatchability than hens inseminated in the morning. Under natural mating conditions Gracewski and Scott (1943) found that restricting the sexual activity of the males to the afternoons increased fertility significantly. In order to . . .