The significance of the zona-free hamster oocyte test for the evaluation of male fertility

Results of the zona-free hamster oocyte test were compared with pregnancy rates after coitus and after artificial insemination with donor semen (AID) in 322 primary infertile couples. Artificial donor insemination was offered if in the test the percentage of hamster oocytes with at least one decondensed sperm head (oocyte-sperm interaction rate) was less than 20. If the rate was less than 5, the pregnancy rate after coitus was significantly lower than in the group with a rate of greater than or equal to 5 to less than 20. In the former group, the pregnancy rate by AID was significantly higher than the pregnancy rate by coitus. We conclude that the zona-free hamster oocyte test is useful to predict the chance to achieve pregnancy in couples with unexplained infertility and to determine whether AID can increase this chance.

Relative efficiency of therapeutic donor insemination using a luteinizing hormone monitor

A prospective randomized study was performed to evaluate the use of a urinary luteinizing hormone (LH) detection kit with 1 insemination as compared with 2 alternate day inseminations with timing based on previous cycle length and basal body temperature changes. The study involved 60 patients who underwent a total of 264 therapeutic donor insemination cycles using cryopreserved semen specimens. Patients alternated LH-kit timed cycles with cycles timed by non-LH methods for a total of 6 cycles or until pregnancy was achieved. Fecundability rates were 12.3% for LH-kit cycles and 5.3% for non-LH method cycles. The difference in outcome was not statistically significant. However, when the LH kit plus 1 insemination was compared with 2 inseminations timed by conventional methods, there appeared to be a distinct monetary and time expenditure advantage. These findings suggest that sufficient advantage may be derived from use of an LH kit to recommend its use on a routine basis for the timing of therapeutic donor insemination.

[Biological manifestations of the andropause]

Aging in men is accompanied by signs of decreased virility and fertility: testicular volume, muscle mass, pilosity, sexual activity, daily production of spermatozoa, plasma testosterone levels, the number of Leydig cells and blood supply of the testicles decrease significantly with age. The pulsatility of LH levels in young and elderly men has been studied by taking plasma samples with an interval of 10 minutes for 12 hours. Age alterations at the hypothalamic-pituitary levels of testosterone production and an increase in gonadostat sensitivity to hormonal influences realized via the feedback mechanism are found. Whenever androgen therapy of eugonadal elderly men is considered, a sufficient dosage should be administered, as otherwise, due to the feedback effects, administered androgens, suppressing endogenous secretion might not increase plasma-testosterone levels. Changes in neurotransmitters and neuromodulators play a determinant role in the sexual behaviour of elderly men.

The reliability of menses to indicate the return of ovulation in breastfeeding women in Manila, The Philippines

Demographic studies generally use menses to indicate the return of fertility during breastfeeding. In a prospective study of 40 breastfeeding women in Manila, the resumption of ovarian activity was monitored by urinary hormone assays, and menstrual status was determined by weekly interview. For the women who menstruated before six months postpartum, first menses was not a good indicator of ovulation because there was a high proportion of anovular menses (67 percent), and the lag between anovular first menses and subsequent ovulation was 15.7 (+/- 4.4) weeks. After six months postpartum the proportion of anovular first menses declined to 22 percent, and the lag between anovular first menses and ovulation was 7.3 (+/- 4.6) weeks. If all anovular and ovulatory menstrual episodes are considered, the mean interval between first observed menses and first ovulation was 8.4 weeks during the first six months postpartum and only 0.1 week after six months. Thus, in breastfeeding women, menses is an inaccurate proxy measure for the timing of fertility return before six months postpartum, but a good indicator of the resumption of ovulation after six months.

[Hygienic standardization of electromagnetic radiation from two-channel meteorological radar stations]

The study was designed to analyze the impact of the combined electromagnetic fields (EMF) with the wavelength of 10 and 0.8 cm and various levels of energy current density on the central nervous system, metabolic processes, immune resistance and reproductive function. Proceeding from the obtained data maximum allowable levels of EMF produced by the prospective two-channel meteorological++ radars were established.

[Reproductive and menstrual functions in women after cryosurgical treatment of cervical diseases]

Short- and long-term results of patients with a history of cryosurgery of cervical pseudoerosions suggested a lack of its adverse effects on reproductive and menstrual function. Cryotherapy of the uterine cervix resulted in normalization of local immunity, an advantage in the presence of a cervical factor of infertility.

Twinning in cattle: II. Genetic and environmental effects on ovulation rate in puberal heifers and postpartum cows and the effects of ovulation rate on embryonic survival

The potential of ovulation rate before 18 to 21 mo of age in puberal heifers as an indirect selection criterion for twinning rate was considered. Heritability (h2) was .07 +/- .03 for single observations and .34 +/- .18 for the mean of 7.9 estrous cycles per heifer. Estimated repeatability (r) of ovulation rate was less than or equal to h2, indicating negligible permanent environmental effects. Expected h2 for mean ovulation rate (assuming h2 = r = .07 for single observations) for increasing numbers of estrous cycles would be as follows: 4, .23; 6., 31; 8, .38; and 10, .43. About 50% of the heifers produced no multiple ovulations, but 27% produced multiple ovulations in more than 15% of their estrous cycles. Ovulation rate varied seasonally and increased about .01 per month of age (P less than .05). Genetic correlation of mean ovulation rate with adjusted 368-d weight was low (.08 +/- .32). Ovulation rate in postpartum cows was higher (P less than .05) in fall than in spring (1.15 vs 1.08). In postpartum cows, estimated h2 = .24 +/- .13 and r = .17. Mean ovulation rate for postpartum cows was 1.12 vs 1.09 in puberal heifers, accounting in part for the higher h2. Pregnancy rate was higher (P less than .05) in multiple- than in single-ovulating cows. Effects of ovulation rate on embryonic survival were small (P greater than .05). Unilateral and bilateral multiple ovulations were not different in embryonic survival. Accuracy of ovulation rate determination by palpation per rectum was lower in multiple- than in single-ovulating postpartum cows, because some unilateral multiple corpora lutea, especially, were recorded as singles. Results suggest that use of ovulation rate in puberal heifers should permit effective indirect selection for twinning rate among yearling heifers based on individual performance and among young sires based on ovulation rate of sibs and daughters.

Metabolic balance and reproductive performance in Finnish dairy cows

The relationships between energy level and reproductive performance were studied in 24 dairy cows, which were fed grass silage. Serum glucose and blood acetoacetate (AA) and beta-hydroxybutyrate (HB) were measured 10, 15, 30 and 50 days postpartum. The cows were examined clinically by rectal palpation 3 times a week during 8 weeks postpartum. The time required for the complete uterine involution and the onset of ovarian activity were recorded. The pregnancy rate at the first insemination and the interval from calving to conception were obtained for each cow. The correlations between blood glucose and ketone bodies were negative, but they were significant only at days 15 and 30 for AA and at day 30 for HB. A low energy level in early puerperium caused a delay in uterine involution and in the onset of ovarian activity. The low energy balance in puerperium prolonged the interval from calving to the first insemination and the interval from calving to conception. The earlier the ovarian activity started the shorter was the interval from calving to conception. The energy level in early puerperium had a greater influence on the interval from calving to conception, whereas in late puerperium it was more important with regard to the interval from calving to the first insemination. Blood glucose had also a significant effect on the reproductive performance. The adverse influence of ketone bodies on fertility depended on duration and timing of their increased levels; the longer and later in puerperium the cow has elevated ketone bodies, the lower is the fertility.(ABSTRACT TRUNCATED AT 250 WORDS)

Subfecundity according to the age of the mother and the father

Time to pregnancy according to the age of the father and the mother has been studied among 10,886 couples from Odense and Aalborg. Late in their pregnancy (36th week) all woman in the two cities were given a questionnaire on time to pregnancy as well as a number of other items. Eighty-six percent responded to this questionnaire, and data concerning previous pregnancies, the outcome of the pregnancy in question, etc., were later collected from medical files. The study showed a strong correlation between mother's age and subfecundity, even after adjustment for a number of potential confounders. The association between subfecundity and the age of the father was much weaker and did not reach statistical significance. Interpretations and implications of these findings are discussed in the paper.

Seasonal variation in fertility, fecundity and litter sex ratio in laboratory and wild stocks of house mice (Mus domesticus)

Data compilations were made for three parameters pertaining to reproduction in a domestic strain (14 years) and a wild stock (4 years) of commensal house mice: (a) the percentage of females mated that produced litters; (b) the average number of pups per litter; and (c) the sex ratio of the pups in the litters. Fecundity and fertility varied seasonally in both domestic and wild mice. More females become pregnant and litter sizes were larger in the spring, summer, and fall months than during the winter season. Sex ratios also varied seasonally with more male biased litters produced during the 4 winter months. There appear to be seasonal shifts in productivity for both stocks of mice and these seasonal trends have not been altered by domestication under laboratory conditions. In spite of the fact that house mice are generally opportunistic, it is possible that there has been selection in the mice for shifting rates of production in relation to the best seasons of the year in terms of climate and resource availability. The higher production of males during summer months may be geared toward greater success in dispersal at that season and a higher probability that the males can find a territory and mate successfully in summer rather than winter. These results have potential implications for animal breeders and for those who maintain mouse colonies to produce animals for scientific investigations.

Hormonal basis of variation in oestrous cyclicity in selected strains of mice

Reproductive hormone secretion and ovarian LH receptor content were studied during the oestrous cycle of mice that differed in fertility after genetic selection. Strain variation in the secretory pattern of progesterone was observed along with differences in the timing and magnitude of prolactin release. Scatchard analysis showed similar affinities of the LH receptor for hCG in strains with increased or decreased reproductive performance, with a single order of binding sites during both pro-oestrus and dioestrus. The number of unoccupied LH receptors during pro-oestrus was greatest in mice with increased reproductive performance. These results provide evidence that trait selection can change gonadotrophin receptor concentration and the dynamics of hormone secretion during the oestrous cycle of the mouse.

[Hormones, reproductive behavior and fertility in male silver foxes]

The relationships between gonadal and glucocorticoid hormones and reproductive behaviour were estimated in two groups of silver fox males classified as either low or high sex activity. Levels of testosterone and cortisol in peripheral plasma measured by radioimmunoassay did not differ between the groups. However, when receptive females were introduced to experimental males, levels of testosterone in plasma increased significantly only in the males with high sex activity within 1 hr after a test of sexual behaviour. Low sex activity of silver fox males correlated with an increased level of aggressive behaviour and decreased fertility.

Rhythmic occurrence of sexual behavior and egg laying activity of Muscovy ducks

1. The existence of nychthemeral rhythms in the sexual behaviour of Muscovy ducks, kept under intensive husbandry conditions, was investigated. Studies were also carried out of the relationships between artificial insemination or natural mating times, oviposition time and female fertility. 2. Sexual activity (as measured by the number of complete matings observed) followed a trimodal pattern with peaks of activity in the second to third, 5th to 6th and 10th to 15th hours of the photoperiod. The last peak in sexual activity was the most important in both length and intensity. 3. The rhythm in sexual activity was entrained by the light-dark transition. 4. Female fertility was lowest during the period from 4 h before to 1 h after oviposition and greatest in the periods 8 to 4 h before and 1 to 7 h after oviposition. 5. The periods of maximum female fertility did not coincide with the periods of greatest sexual activity. More than 60% of all matings observed occurred during periods of intermediate female fertility. It would therefore appear that natural mating is not consistent with optimal female reproductive performance under artificial husbandry conditions. 6. The results are discussed in relation to a possible reduction in the number of males necessary in breeder populations in Muscovy ducks with a view to reducing the cost of producing ducklings.

Nutrition and postpartum rebreeding in cattle

Body weight and condition score, although perhaps imprecise or subjective, are functional indicators of energy status and rebreeding performance after calving. Inadequate precalving and(or) postcalving energy or protein nutrition lowers pregnancy rates as well as first-service conception rates and extends postpartum intervals in suckled postpartum beef females. Normal nutritional regimens for dairy cows that are fed for maximal lactation do not exhibit long postpartum intervals or reduced fertility. Yet excessive protein intake may depress postpartum rebreeding performance, especially in older dairy cows. Feeding of ionophores, with increased ruminal propionate levels in the rumen, results in an earlier return to estrus postpartum. Underfeeding of the postpartum cow extends the period of ovarian inactivity. The underfed postpartum cow's lack of ovarian activity appears to be due to a suppression of the pulsatile release of LH from the anterior pituitary gland, which in turn is controlled by release of GnRH from the hypothalamus. Some metabolic compound(s) presumably act on the hypothalamic-pituitary-ovarian axis as the nutritional state of the animal is altered.

Suckling as a regulator of postpartum rebreeding in cattle: a review

An extended and variable period of anovulation and anestrus occurs in suckled beef cows following parturition. This imposes both biological and economic constraints on the efficiency of beef production. A large body of knowledge has linked these phenomena to an attenuation of neuroendocrine signals that subserve gonadal function. During late gestation, high concentrations of placental estrogen inhibit the synthesis of LH, and pituitary stores of LH are depleted at parturition. Maximum pituitary stores of LH, releasable pools of LH and the ability of hypothalamic centers to respond to positive feedback effects of estradiol occur within 3 to 4 wk after calving in suckled cows. However, the requisite pattern of pulsatile LH secretion, which accompanies similar changes in nonsuckled cows within 2 to 3 wk after calving, occurs in only 30 to 50% of suckled animals. The period of acyclicity that continues in the remainder is exacerbated by poor body condition and may persist in some females for periods exceeding 100 d. Utilizing data from the cow, as well as other species, a model for suckling-induced inhibition of pulsatile LH release is proposed. The biological and economic impact of current and future techniques for controlling suckling-induced anestrus also is considered, including a conceptual analysis of nonbiological limitations.

Fertility of mares after postovulatory insemination

In a first experiment, 11 Finnhorse mares were examined every six hours during late oestrus by rectal palpation and ultrasonography to determine the time of ovulation. The mares were inseminated over one to three subsequent cycles, 6-12 (n = 5), 12-18 (n = 5), 18-24 (n = 5) and 24-30 (n = 5) hours after ovulation. Pregnancies were terminated by prostaglandin injection 21 days after insemination. All mares inseminated within 18 hours of ovulation conceived but no mare inseminated 24 hours or more after ovulation conceived. In a second experiment, 14 mares were examined every day at about the same time and inseminated after ovulation had been detected, within 0-27 hours of ovulation. Pregnancies were terminated by prostaglandin injection 25 days after insemination and the animals inseminated again. Forty-six per cent of the mares (13 out of 28) were pregnant 16 days after insemination but there was early embryonic death in five mares, i.e. only 29% of the mares became and remained pregnant. The equine ovum seems to be capable of being fertilized for at least 18 hours after ovulation. However, the high incidence of early embryonic death in the second experiment suggests that the viability of the embryo may have decreased.

Effects of various feeding regimens on reproduction in broiler-breeder males

A study was conducted using commercial broiler-breeder males and females maintained in all-litter pens allowed to mate naturally. Using a separate feeding arrangement, males were given a diet containing either 12% or 14% protein. Body weights were maintained at either 90% or 100% of the recommended level. Females were provided feeders with grills which denied males access to the feed, while male feeders were elevated 46 cm above the floor to deny female access to that feed. In control pens, males and females ate from the same feeders and received a breeder diet with 14% protein. Eggs produced in pens where the males and females were fed separated showed significantly higher fertility (4.2%) than eggs from control pens. No differences in percentage fertility were noted between the two dietary-protein levels or body-weight groups of males fed separately. Furthermore, no differences were measured in percentage hatch of fertile eggs among any of the treatment groups. Males in control pens showed significantly heavier body weights and breast-angle measurements starting at 32 and 40 wk of age, respectively. No treatment effect was measured for male pododermatitis. The male control birds had heavier testes weights than the males in the groups with restricted body weights. However, semen concentration was not affected. This indicates that the improved fertility was related to the size and weight of the males, not to their ability to produce semen. The reduced fertility associated with excess male body weight may be both physical and physiological in nature.

Decreased spermatozoal survivability associated with aberrant morphology of the ductuli efferentes proximales of the chicken (Gallus domesticus)

The objective of this research were twofold: 1) to determine if decreased spermatozoal longevity, a previously reported heritable trait in chickens, was attributable to spermatozoal passage through the excurrent ducts, and 2) to document the morphology of the testicular excurrent ducts from affected roosters. Though spermatozoa were viable at ejaculation, as evidenced by their exclusion of ethidium bromide, fertility after intravaginal insemination of spermatozoa from affected roosters was less (p less than 0.001) than that observed with spermatozoa from nonaffected controls, 37 +/- 2.3 versus 58 +/- 1.5%, respectively, over a 21-day egg-collection interval. In contrast, fertility after intramagnal insemination of testicular spermatozoa from affected roosters was equivalent (p greater than 0.05) to that of nonaffected controls, 47 +/- 2.2 versus 41 +/- 3.6%, respectively. After intravaginal insemination, neither type of testicular spermatozoa fertilized oocytes. The ductuli efferentes proximales from affected roosters were characterized by a greater luminal cross-sectional area as well as a diminished height and number of longitudinal epithelial folds (p less than 0.005). It was concluded that heritable decreased spermatozoal longevity in the chicken is not attributable to an inherent spermatozoal defect. Rather, the defect is acquired during passage of spermatozoa through the extragonadal ducts of the rooster.

Seminal vesicles: development, secretory products, and fertility

The development of the seminal vesicle from the mesonephric duct is described. Particular attention is given to the recent biochemistry of seminal vesicle proteins. Proteins in the seminal vesicle fluid are few in number, may be insoluble at certain pH, and frequently form large macromolecular aggregates. Although not an absolute requirement for fertility, seminal vesicle fluid assists in a number of ways to insure fertility. A biochemical model is presented that demonstrates that cAMP dependent phosphorylation may be an important interaction between sperm and certain seminal vesicle proteins.

Hypo-osmotic swelling test: analysis of prevasectomy ejaculates

The hypo-osmotic swelling (HOS) test was applied to 1,890 ejaculates obtained from previously fertile men who subsequently underwent a vasectomy. Less than 3% of the ejaculates produced an abnormal HOS test (less than 50% swelling), and more than 95% were normal (greater than or equal to 60% swelling). The sperm concentration and motility data were similar to those obtained by other investigators with prevasectomy ejaculates. Statistically significant but low correlation coefficients were present between the HOS test and these other sperm variables. On the assumption that the large majority of these men were fertile when the ejaculates were produced, the results support the contention that fertility is usually associated with normal or, occasionally, equivocal values in the HOS test.

Fertility of sows mated on different days of the week

The farrowing rates resulting from matings on different days of the week were determined for a 2800-sow intensive piggery in both 1983 and 1984. The results showed that sows mated early in the week achieved a significantly higher farrowing rate than sows mated late in the week (P less than 0.0001). During the seasonal (summer to autumn) infertility period, Wednesday matings resulted in a poor farrowing rate whereas for the rest of the year farrowing rates following Wednesday matings were similar to those for Sunday Monday and Tuesday matings. Consistent results were obtained for data from both years. It is proposed that the stress of regrouping unmated sows on Wednesday to accommodate newly weaned sows is responsible for this decrease in fertility. This study illustrates how detailed analysis of farrowing rates on a day of mating basis can identify a problem which is otherwise masked by weekly data.

Smoking does affect fecundity

A total of 2198 mothers were interviewed at the 20th week of pregnancy and their smoking habits before pregnancy and the time from discontinuation of contraception to the beginning of the pregnancy were registered. This information was used to investigate whether smoking affects conception delay; i.e., fecundity and a multifactorial analysis were used. The longer the conception delay, the more significant was the deleterious effect of even light smoking, the odds ratio shifting from 1.1 at 6 months to 3.2 at 18 months. The effect of smoking on fecundity seemed to be mostly dose-dependent. In mothers becoming successfully pregnant in 12 months, both maternal and paternal smoking increased the risk of conception delay (OR 1.5 and 1.3), and the effect was potentiated by increasing age (OR 2.3 and 1.6). In addition to smoking, previous recurrent spontaneous abortions were also associated with fecundity.

The recovery of fertility during breast-feeding in Assiut, Egypt

A longitudinal study of twenty-six breast-feeding and twelve non-breast-feeding postpartum women was conducted in Assiut, Egypt in order to determine the time that ovulation resumed after childbirth, and the effect of breast-feeding frequency on the period of lactational anovulation. Breast-feeding women experienced the onset of follicular development, vaginal bleeding, ovulation and pregnancy significantly later than women who did not breast-feed. Ovulatory and non-ovulatory breast-feeders reported similar frequencies of breast-feeding episodes. The introduction of dietary supplements commonly preceded ovulation. An algorithm using three simple variables observable to the breast-feeding mother was found to predict up to 100% of the first ovulations. All breast-feeding women who did not give supplements and did not have a vaginal bleeding episode by 6 months postpartum were anovular by strict criteria for ovulation. Ovulation did not precede bleeding or supplementation in the women who experienced these events before 6 months, yielding a highly effective formula for preventing unplanned pregnancy by the informed use of breast-feeding.