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At least 19 recordsLinked to original sources
PubMed1979

Infertility in the turkey. III. Effects of sera from sterile and fertile females on the fertilizing ability of spermatozoa.

In an attempt to understand the cause for spontaneous infertility in female turkeys, sera were obtained from a flock suffering this condition. These sera, from hens of known fertility, were tested for anti-fertility actions by incubating semen in them. After incubation, semen was inseminated into unrelated recipient hens. In the first of two experiments, semen incubated in sera from high fertility hens (average 89%) produced a fertility level of 72.7% over an 8 week period while semen incubated in sera from sterile hens significantly reduced fertility to 52.3%. In a second experiment sera from sterile donors again caused a significant reduction in the fertilizing ability of sperm (56.3% for sera from sterile hens vs. 73.5% for sera from high fertility hens). These results indicate the presence of a factor(s) in the sera of sterile hens which may be causally related to their infertility.

Animals↗
PubMed1978

Age, biological factors, and socioeconomic determinants of fertility: a new measure of cumulative fertility for use in the empirical analysis of family size.

To influence the number of children ever born to a woman, socioeconomic variables must operate through behavioral and biological mechanisms such as the age at marriage, the level of fertility in the absence of deliberate fertility control, and the level of control exerted to reduce fertility within marriage. In this paper, we propose a new measure of cumulative fertility which is standardized for the age-fecundity relationship and for exposure to the risk of conception associated with duration of marriage. A simple model of fertility behavior which incorporates some of the mechanisms through which socioeconomic factors may affect fertility is developed and applied to data from the United States to demonstrate the properties of alternative measures of family size. The results indicate that use of the new measure allows more precise estimates of socioeconomic fertility relationships than would be obtained with children ever born or by sample stratification.

Adult↗
PubMed1975

[Fertility and fertility problems in some beef herds in Sweden (author's transl)].

The purpose of the study was to investigate the fertility level, some factors affecting fertility and problems of infertility in selected Swedish beef herds. The investigation included 31 herds, 19 of which had Herefords, 13 Charolais, 2 Aberdeen Angus and 1 Limousins. The total number of mature females was 703, including 147 feifers of breeding age. Most data were collected at personal visits to the herds. The results are presented in Tables I--XV and Figures 1--2. The service period coincided roughly with the grazing period and lasted usually 4--5 months. Seventyfive per cent of the females calved during the period February-May. The fertility levels were comparatively good. The percentage of pregnancy at rectal examination performed at the end of the service period was 89.5; however the average calving percentage was only 87.5. The highest calving percentages were recorded for Aberdeen Angus and crossbreds. Also the calf crop, it is the number of calves born alive and surviving 24 hours per mature female was the highest for these two groups; 0.91 and 0.90 respectively. The mean interval from calving to conception was 80.3 days in Herefords, 83.4 days in Aberdeen Angus, 85.6 days in crossbreds and 92.3 days in Charolais. The percentage of animals pregnant within 90 days after calving was on an average slightly more than 50 per cent. The interval from calving to conception rose gradually when the interval from calving to expoure to bull exceeded 40 days. Mean percentages of still born calves were 5.9 in cows and 13.7 in heifers. As far as the fertility level is concerned there does not seem to be any disadvantage in keeping the bull together with the females during the calving period. However, in this case the next calvings will occur over an extended period of time. If the intention is to concentrate 50 per cent of the calvings within the period of one month then the females should be exposed to the bull from 41--60 days after calving at the earliest. In case the females were exposed to the bull from 41--60 days after calving and onwards, 95 per cent of the females finally pregnant had conceived at the end of a 3 months service period. Under such conditions a bull may be able to serve two groups of females within the same grazing period. Cows calving during July-September had the lowest pregnancy rate and those calving during October-December the highest at the following service period. The incidence of ovarian cysts was very low. About 1/3 of those buls serving at least 10 females each obtained calving percentages less than or equal to 80. Herds recording low calving percentages had to a great extent used young bulls, 12--15 months of age at the beginning of the service period. Only for two groups of females out of eleven which had been served by young bulls calving percentages greater than 80 were noted. A more efficient control of the fertility of the bulls could markedly improve the fertility of some herds.

Abortion, Veterinary↗
PubMed1977

[The decline of fertility in Western Europe. II. Which fertility rate would be desirable in France? (author's transl)].

A way to try and assess the significance of such or such level in long term fertility is to work out population projections based on a variety of assumptions and to compare their different implications. The age pyramids of France until 2100 that derive from four contrasted evolutions of fertility are studied in the present article: completed fertility in birth cohorts ranging from 1.4 to 2.6 children per woman. While some demographic parameters are not much sensitive to the assumption made for the fertility level (e.g. percent of economically active people in total population), others are closely related to fertility (such as total number of inhabitants, percent of younger people or of older people in total population, annual rate of entry into economically active population). In France, where population density is much lower than in most neighbouring countries, a fertility level that would lay at -- or a little higher than -- replacement (i.e. 2.1 children per woman) can be considered as a desirable target.

Adolescent↗
PubMed1977

[The decline of fertility in Western Europe. III. Some considerations on future evolution and on policy measures aiming at supporting fertility (author's transl)].

The analysis of recent fertility trends in France lead to hold as plausible that women born after 1950 will not reach replacement level. On the other hand, the period total fertility rate, which has not fallen as low as those observed in some neighbouring countries, might well continue to decline and thus disturb the alimentation of age-pyramid, despite its slower decrease in the course of 1976. Considering present fertility situation in France, an action of the State appears to be desirable. The factors which condition fertility fall largely out of the range of well-established knowledge. Though, it seems that they are deeply rooted in collective consciousness and that the possibilities they leave to voluntary action on fertility trends is relatively modest. Moreover, to be efficient, the means used must be important. The lines of possible action seem, in our view, to relate to two main fields: research of a better conciliation of professional activity and motherhood, increase of family benefits for second but specially for third and following children.

Birth Rate↗
PubMed1975

In vitro fertilization of rat and mouse eggs by ejaculated sperm and the effect of energy sources on in vitro fertilization of rat eggs.

In vitro fertilization of rat and mouse eggs by ejaculated or epididymal spermatozoa in chemically defined media was studied. Penetration rates by ejaculated sperm was very low (0 to 8%) in the rat, but 11 to 41% of eggs were penetrated by ejaculated sperm in the mouse. The optimal concentration of sperm for in vitro fertilization appears to be similar whether ejaculated or epididymal sperm were used. The time of sperm penetration in the mouse eggs, however, was delayed for one-half to one hour when ejaculated sperm were used. The importance of sodium pyruvate, sodium lactate and glucose in the medium containing bovine serum albumin for in vitro fertilization of rat eggs was examined. When rat eggs in cumulus clot were exposed to epididymal sperm preincubated for five hours, the presence of sodium pyruvate, sodium lactate and glucose was found to play an important role. When exposed to non-incubated epididymal sperm sodium pyruvate could be omitted without much decline of the fertilization rate. When the denuded eggs were exposed to non-incubated sperm, penetration rates were very low (0 and 5%) in the absence of pyruvate. It appears that although lactate, pyruvate and glucose are all important for in vitro fertilization of rat eggs, pyruvate can be supplied by the follicular cells surrounding the eggs.

Animals↗
PubMedDate not supplied

The U.S. fertility decline, 1961-1975: the contribution of changes in marital status and marital fertility.

Changes in marital fertility have accounted for 83 percent of the decline in total fertility since 1971; changes in marital status accounted for 19 percent, and changes in nonmarital fertility had only a negligible effect. Declines in the level of marital fertility account for a substantial part of the overall decrease; postponement of childbearing did not occur in any significant degree until the 1970s.

Adolescent↗
PubMed1979

From natural fertility to family limitation: the onset of fertility transition in a sample of German villages.

Utilizing data from a sample of German village genealogies, it is possible to document the changes in reproductive patterns on the family level that started to take place in Germany during the nineteenth century and formed the basis for the secular decline in fertility which eventually encompassed the entire country. One striking finding from this study was the substantial diversity among the small sample of villages in terms of the timing of the emergence of family limitation. While couples in all villages who married during the last half of the eighteenth century appeared to be characterized predominantly by natural fertility the emergence of family limitation began as early as the turn of the nineteenth century in some places and as late as the end of the nineteenth century in others. Occupational differentials with respect to family limitation were also examined. There is little evidence that changes in birth spacing played an important part in the initial phase of the fertility trnsition. Rather, the underlying process appears to involve a change from fertility patterns that were characterized by the absence of parity-dependent control to one in which attempts to terminate childbearing in response to the number of children already born becomes widespread.

Age Factors↗
PubMed1978

Murine cytomegalovirus and fertility: potential sexual transmission and the effect of this virus on fertilization in vitro.

Male mice were inoculated with murine cytomegalovirus (MCMV) to produce an acute generalized infection. Infections virus was recovered from both epididymal sperm and seminal vesicles as well as from uterine sperm collected from mated females, suggesting that MCMV might be transmitted sexually. Because the presence of virus in the ejaculate might affect the fertilization process, the effect of MCMV on the fertilization of mouse gametes and on subsequent embryonic development was studied in vitro. Although the fertilization rate was reduced when sperm were preincubated with infectious virus, this was also the case when heat-inactivated virus was used, leading to the conclusion that this effect was not due to a direct infectious interaction between virus and gametes. Subsequent embryonic development was normal, and there was no evidence of productive infection of the preimplantation embryo.

Animals↗
PubMed1976

Immunological block to mammalian fertilization: survival and organ distribution of immunoglobulin which inhibits fertilization in vivo.

Fertilization of golden hamster eggs was blocked both in vitro and in vivo by antibodies produced in rabbits against specific hamster ovarian antigens (HOA). Antibodies against HOA bound to surfaces of the hamster egg zona pellucida and prevented spermatozoa from attaching to the zona and entering eggs in vitro. Fertilization in animals could be blocked for four estrous cycles by a single intraperitoneal injection of anti-HOA immunoglobulin, but not by control immunoglobulin. The in vivo fate of anti-HOA immunoglobulin was analyzed by simultaneous injection of 125I-anti-HOA IgG and control 131I-IgG. Both anti-HOA IgG and control IgG appeared in a variety of organs (lung, kidney, spleen, liver, and uterus) shortly after injection, but disappeared rapidly with no detectable differences in organ half lives. However, in the ovary anti-HOA IgG (but not control IgG) persisted at high levels during the period of infertility. Quantitative precipitin analysis of organ homogenates indicated that a high percentage of anti-HOA IgG in the ovary (but not in the other organs tested) was immunologically indistinguishable from IgG indicating lack of radiolabel metabolism and reincorporation. The results are discussed in terms of the development of a specific immunological block to fertility.

Animals↗
PubMed1992

[What results can be expected from in vitro fertilization and other technics of assisted fertilization?].

Results of assisted reproductive techniques (IV, GIFT and ZIFT) have improved progressively during the last years but they are still not satisfactory specially when they are analyzed in terms of cost efficacy. During 1990, in the world literature, the following successful results were reported: pregnancy rates of 20% and delivery rates of 15% for IVF-ET, 29% and 22% for GIFT and 21% and 16% for ZIFT. In spite of the small number of cases reported in Chile, results are similar to those of USA and Europe. Results of assisted fertilization techniques have improved with the use of Gn-RH agonists and are worse in patients older than 35 years of age than in younger ones. Pregnancies rates are higher when the number of transferred ovocytes increases although transfer of more than 3 or 4 ovocytes or embryos is contraindicated because of the risks of multiple pregnancies. When more than 3 or 4 embryos are obtained those not transferred are usually cryopreserved. IVF-ET is the first choice of treatment in cases of infertility due to severe tubal damage and/or extensive and dense pelvic adhesions. In cases of infertility with normal tubes, intrauterine inseminations in 3 to 4 controlled hyperstimulated cycles are recommended before indicating an assisted fertilization procedure. The most risky complication of assisted reproduction, besides multiple pregnancy, is severe ovarian hyperstimulation syndrome (SOHS). This syndrome is prevented by not injecting HCG or by not transferring ovocytes or embryos in cases of high estradiol levels after HMG and/or FSH administration.

Adult↗
PubMed1975

The semen of fertile men. II. Semen characteristics of 100 fertile men.

From a population of men applying for voluntary sterilization, 100 consecutive cases were selected according to the following criteria: (1) each man had fathered at least two children; (2) at the time of the request for a vasectomy the man's wife was pregnant; and (3) a complete prevasectomy semen analysis, including sperm morphology, was available. The usual parameters of human semen evaluation are reported: the mean volume of the ejaculates was 3.3 ml +/- 0.84 SD (range, 0.5 to 11 ml); the mean sperm density was 81 million/ml +/- 57 SD (range, 4 to 318); while the geometric mean, which according to the sample distribution is more representative, was 68. The mean percentage of motile sperm was 63% +/- 16 SD (range, 10 to 95%); the grade of forward progression was 3 +/- 0.55 SD (range, 2 to 4); and for sperm morphology the mean number of sperm with oval heads was 75% +/- 6 SD (range, 21 to 90%). Statistical comparison of these findings with those of our previous study of the semen of 1300 fertile men revealed complete agreement; minor statistical differences, on single parameters, with three similar studies are indicated. A positive relationship between the different variables, sperm density and sperm motility (in percentage of motile sperm and degree of forward motion), as well as between the two variables of sperm motility and sperm morphology to the other variables was confirmed.

Adult↗
PubMed1979

Prevention of in vitro fertilization of canine oocytes by anti-ovary antisera: a potential approach to fertility control in the bitch.

Antisera raised against canine ovaries were found to induce light scattering of the surface of the egg zona pellucida even when diluted 10,000 times, and to delay digestion of the zona by pronase. High concentrations of antiserum were required, however, to inhibit in vitro fertilization of the oocytes. Absorption of the antisera with canine ovaries removed these effects, whereas absorption with liver, uterus and serum did not. These results demonstrate the antigenicity of the canine ovary and suggest the plausibility of an anti-zona pellucida vaccine for bith control in the bitch.

Animals↗
PubMed1975

Fertilization of rat eggs in vitro at various times before and after ovulation with special reference to fertilization of ovarian oocytes matured in culture.

Oocytes recovered at various times from immature rats treated with PMSG and HCG were incubated with capacitated epididymal spermatozoa of mature rats. In the presence of follicular cells, sperm penetration was not observed 4 hr after incubation in the oocytes at stages from the intact germinal vesicle to the chromatin mass, but 7 to 55% of oocytes were penetrated at stages from the condensed germainal vesicle to metaphase II. After the removal of follicular cells, 15 to 72% of the oocytes at any stage were penetrated. After further incubation for 15 hr, the proportion of penetrated oocytes increased from 8 to 98% from early to late stages and that of penetrated oocytes with a male and female pronucleus increased from 9 to 100% as maturation progressed. Although the average number of spermatozoa/oocyte was not correlated with its maturation, transformation of the sperm head into a male pronucleus was retarded or failed, especially in the younger oocytes. Following incubation in a defined medium for 13 hr, 85% of oocytes at the intact germinal vesicle stage matured to the stage of the first polar body formation, but only 18 to 22% of these mature oocytes were penetrated by spermatozoa and only a few of the penetrated oocytes cleaved into normal two-cell eggs. When eggs recovered from oviducts 14 to 20 hr after ovulation were exposed to capacitated spermatozoa, the proportion of penetrated eggs (86 to 98%) and that of polyspermic eggs (11 to 27%) were not related to the ages of the eggs, but failure of transformation of the sperm head and the proportion of abnormal eggs increased 14 to 20 hr after ovulation.

Animals↗