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PubMed2006

Variance components for live weight, body measurements and reproductive traits of pair-mated ostrich females.

Estimates of genetic parameters for reproductive traits, live weight and body measurements were obtained using data from a pair-mated ostrich flock at Oudtshoorn in South Africa. Reproductive traits included total egg and chick production, along with hatchability percentage. Live weight, chest circumference and tail circumferences were recorded at the commencement and cessation of breeding. Heritability estimates (h(2)) were 0.23 for egg production, 0.20 for chick production, 0.10 for hatchability, 0.20 to 0.34 for live weight, 0.12 for chest circumference and 0.30 to 0.38 for tail circumference. Female permanent environmental effects (c(2)) amounted to 0.18 for egg production, 0.18 for chick production, 0.21 for hatchability, 0.32 to 0.36 for live weight and 0.23 to 0.32 for chest circumference. Service sire exerted significant effects only on hatchability (0.22) and subsequently chick production (0.09). Genetic correlations of reproductive traits with live weight were low to moderate, variable in sign, and did not differ significantly from zero. Correlations between live weight recorded at the beginning and end of the breeding season were unity for additive genetic and permanent environmental effects. Egg and chick production were highly correlated genetically and phenotypically, with the genetic correlation exceeding the theoretical limit. In unconstrained analyses, hatchability was positively related to chick production, including at the service sire level. Selection gains in the current flock and future generations are likely. No significant adverse relationships were found between live weight, body measurements and reproductive traits.

Animals↗
PubMed1998

[Effect of estradiol valerate on the male reproductive organs and various semen parameters in rats].

The effect of the administration of estradiol valerate on the male reproductive organs, on their histological structure, and several semen parameters of Wistar rats was studied. In experiment A and B 140 micrograms estradiol valerate/kg b.w. were administered once a week for 4 weeks to 14 weeks old rats by s.c. injection. One week after the 4th injection the rats of experiment A were sacrificed, while the rats of experiment B lived 5 weeks without treatment for recovery. In both experiments, suppression of body weight, food consumption, decreases in absolute and relative weights of testes, epididymides, prostate and semen vesicles were observed along with testis, epididymis, seminal vesicle and prostate atrophy. The absolute and relative weights of adrenals and pituitary revealed a tendency for increase in both treated groups. The histopathological examination of the testes revealed degeneration of spermatozytes in experiment A, and degeneration of spermatozytes, spermatides, spermatozoa, Sertoli and Leydig cells in experiment B. In experiment A the motility, and number of sperms was significantly decreased, the sperm abnormalities were significantly increased. In experiment B the motility of sperms was slightly, the number significantly decreased and the abnormalities slightly increased.

Adrenal Glands↗
PubMed1994

Effects of a daily feeding-restriction on the reproductive and development toxicity parameters in female rats.

On the assumption of that the oral administration of an acid-unstable test compound into the empty stomach could enhance the systemic exposure to the test compound, the non-pregnant and pregnant rats had free access to the diet only for five hours per day. Female rats under the restricted feeding for a period of 21 days took diet at two thirds of the daily food-intake by the control animals, and lost their weight more than 10%. The vaginal smear test in these animals revealed a prolonged estrous cycle and diestrous period over four days. On the other hand, the restricted feeding from Day 0 to Day 17 of gestation suppressed the weight gain of pregnant animals but did not cause any significant influence upon the litter data, incidence of external anomalies or fetal skeletal development. The restricted feeding from Day 0 of gestation to Day 7 of lactation seriously disturbed the nursing behavior and the growth of offspring. These results suggested that the dosing method under the above-mentioned restricted feeding might be applicable to the teratology study but could not be applied to the fertility study nor to the peri- and post-natal study.

Abnormalities, Drug-Induced↗
PubMed1991

Computer simulation model of swine production systems: III. A dynamic herd simulation model including reproduction.

A dynamic herd simulation model for a swine production unit has been developed. The model is discrete and stochastic and the appropriate random distributions have been defined from the literature or empirically estimated. Theoretical concepts and relationships presented previously are used to simulate growth and the overall life cycle of individual animals. Simulated animals are young pigs (from birth to slaughter age), gilts, and sows. Animal events are farrowing, weaning, mating, end-nursery (transfer from nursery to the growing-finishing facility), and slaughter and are processed individually using a next-event scheduling orientation package. Animals within the herd are culled for different health and reproductive reasons. Genetic parameters, diet composition, and herd management are input variables chosen by the user. The effects of nutrition, genetics, season, and other factors on several reproductive parameters are considered. Model evaluation is performed by studying the output of the model under specified herd situations. The herd model adequately simulates animal flow and dynamics of the herd.

Animal Nutritional Physiological Phenomena↗
PubMed2001

Effects of different patterns of feed restriction and insulin treatment during the luteal phase on reproductive, metabolic, and endocrine parameters in cyclic gilts.

The objectives of the present study were 1) to study potential effects of previous nutritional treatment on developmental competence of early fertilized oocytes in vitro; 2) to study responses to insulin treatment during the period of feed restriction in the late luteal phase which has deleterious effects on subsequent fertility; and 3) to establish the metabolic and endocrine status of gilts during treatment and the subsequent periestrous period. Nineteen trios of littermate gilts were subjected to feed restriction during the first (RH) or second (HR) week of the estrous cycle. A second group of HR gilts received injections of long-acting insulin during their period of feed restriction (HR+I). Intensive sampling was performed in a subgroup of 23 animals on d 15 and 16 of the cycle for analyses of endocrine (gonadotropins and steroid hormones) and metabolic (insulin, IGF-I, leptin, total triiodothyronine [T3], and free T3) variables. Gilts were checked for estrus every 6 h, and time of ovulation was monitored by transcutaneous ultrasonography. Surgeries were performed 12 to 20 h after ovulation, and the early-fertilized oocytes recovered were cultured in vitro under standardized conditions. There was no treatment effect on the developmental competence of fertilized oocytes in vitro; however, ovulation rate was increased in HR+I gilts. No effect of treatment was observed on plasma leptin and IGF-I concentrations on d 15 and 16. However, HR+I gilts had higher (P < 0.05) postprandial insulin and lower (P < 0.05) postprandial total and free T3 on d 15. Plasma concentrations of LH, FSH, and progesterone on d 15 and 16 and plasma estradiol concentrations on d 16 were not affected by previous nutritional or insulin treatment. In the periestrous period, plasma concentrations of LH, FSH, and estradiol were higher (P < 0.05) in RH and HR+I, and the rise in plasma progesterone after the LH surge was lower (P < 0.05), than in HR gilts. No effect of treatment was observed on plasma concentrations of metabolic hormones, except on plasma leptin concentrations, which were higher (P < 0.05) at the time of the LH surge in RH gilts. These results suggest that feed restriction during the late luteal phase may have deleterious effects on ovarian function in the periestrous period, which may be counteracted by insulin.

Animals↗
PubMed1986

Genetic parameters and factors affecting reproductive performance in White Fulani cattle in Southern Nigeria.

Data on reproductive performance of the White Fulani (Bunaji) cattle in Southern Nigeria were analysed. Age at first calving, first and overall calving intervals averaged 4.03 +/- 0.43 years, 436.19 +/- 9.32 and 420.98 +/- 4.11 days respectively. The year of birth significantly affected age at first calving and calving interval (P less than 0.01) but the season of birth had significant effect only on calving interval (P less than 0.05). In addition the age of the dam also affected the calving interval (P less than 0.05) but the sex of the calf nursed had no effect. Heritability estimates from half-sib analysis were 0.01 +/- 0.03, 0.26 +/- 0.10 and 0.28 +/- 0.08 respectively for age at first calving, first and overall calving intervals. Low repeatability estimates were obtained for calving intervals.

Aging↗
PubMed1989

Estimation of genetic parameters for production and reproduction in Finnish Ayrshire cattle.

Records of AI-sired cows born between 1978 and 1982 were used to form two composite production and reproduction data sets. First (second) consisted of 35,568 (26,443) first lactations of daughters of 270 (237) sires. Traits were FCM, heifer, and first parity nonreturn rates, days between calving and first insemination, and days open, with means 5075 (5280) kg, .62 (.62), .44 (.49), 81 (81) d and 110 (111) d. (Co)variance components were estimated by REML with an expectation maximization algorithm. Sire model included age, month, herd-year effects, and relationships among sires. Records on animals with observations missing on some traits were included. Estimates of heritabilities, averaged over data sets, were nonreturn rates for heifers and for cows, .02; FCM, .32; days to first insemination, .19; and days open, .10. Genetic correlations between first parity fertility and yield were unfavorable; the highest, .43, was between FCM and days open. Heifer nonreturn rate had a .09 correlation with production and a .26 correlation with cow nonreturn rate. Phenotypic correlations were in the same direction as genetic correlations but were smaller in magnitude. Results suggest that selection only for production would cause deterioration in level of fertility. When economical, AI sires should be evaluated for daughter fertility. A multi-trait model including milk production, days open and relationships among bulls is recommended for genetic evaluation.

Age Factors↗
PubMed1994

[Evaluating the effect of smoking tobacco on some semen parameters in men of reproductive age].

Seminal fluid indexes (sperm count, motility, pH, morphology) were examined in 40 smokers and 30 nonsmokers. The sperm count and motility were lower in smokers. Smokers have also higher incidence of oligospermia compared to nonsmokers. There was no difference between pH and sperm morphology in smokers and nonsmokers. Additionally, smokers have higher levels of endogenous 17 beta-estradiol and sperm count below normal in nonsmokers. These results suggest that inveterate smoking can diminish fertility in men.

Adult↗
PubMed2006

Using reproductive value to estimate key parameters in density-independent age-structured populations.

The dynamics of reproductive value are used to provide a simple derivation of Tuljapurkar's approximation for the long-run growth rate and environmental variance of lnN, in a density-independent age-structured population in a random environment. With no environmental autocorrelation, the dynamics of total population size, N, generally shows time lags and autocorrelation caused by life history, which may strongly bias estimates of environmental variance obtained by ignoring age structure. In contrast, the total reproductive value, V, is Markovian and obeys a first-order autoregressive process. This suggests a simple method for estimating the environmental variance, and avoiding potentially large bias due to age-structure fluctuations, by converting a multivariate time series of age structure to a univariate time series of lnV. We illustrate the method by estimating the long-run growth rate and the environmental variance in an exponentially growing population of Bighorn Sheep.

Age Distribution↗
PubMed2007

Effects of cadmium and tributyltin on development and reproduction of the non-biting midge Chironomus riparius (Diptera): baseline experiments for future multi-generation studies.

In this study the effects of tributyltin (TBT) and cadmium (Cd) were tested on the freshwater arthropod Chironomus riparius (Diptera) in life-cycle experiments. To this end, the OECD guideline 218 was extended with reproduction relevant parameters (e.g. number of fertile egg masses per female). Based on these reproduction data the number of larvae for next generation and the population growth rate were calculated. Experiments were performed using environmentally relevant concentrations of the test substances in the sediment (nominal ranges: 50-200 micro g Sn/kg and 0.2-2.1 mg Cd/kg, on a dry weight basis). Quartz sand was used as sediment in order to develop a test system for a following research project, focusing on the effects of TBT and Cd as model stressors on C. riparius populations in multi-generation studies. Both model stressors caused significant effects on development and reproduction of C. riparius. Larval mortality proved to be a sensitive parameter and a clear concentration-response relationship was observed with a significant increase (P < 0.001) at the highest TBT concentration and at a Cd concentration of 1.17 mg Cd/kg dw (P < 0.05). The two highest TBT concentrations emergence was significantly (P < 0.05) delayed compared to the solvent control. For Cd a clear prolonged average main emergence interval was observed, but not for TBT. TBT and Cd inhibited also oviposition. These effects resulted in a concentration-depended reduction of the population growth rate.

Animals↗
PubMed2004

Gonadotropin-releasing hormone agonist: a new approach to reversible contraception in female deer.

Fertility control offers a potential alternative for controlling an abundance of wild ungulate populations where lethal methods are infeasible or unacceptable. A promising nonsteroidal, nonimmunologic approach to reversible contraception consists of agonist of gonadotropin-releasing hormone (GnRH). We evaluated the effects of the GnRH agonist, leuprolide, on reproduction, the suppression of luteinizing hormone (LH) and progesterone, blood parameters, and reproductive behavior in captive female mule deer (Odocoileus hemionus) during December 1999 through June 2001. Leuprolide, administered as a controlled release formulation (ATRIGEL), was 100% effective in preventing pregnancy for one breeding season. Infertility was achieved by suppressing LH levels, which prevented ovulation and the formation of corpus luteum. Treated females regained normal ovarian function and conceived the following breeding season. Leuprolide had no adverse effects on blood chemistry and hematology, body weight dynamics, or the general health of treated females. In contrast to our predictions, leuprolide did not suppress estrous behavior in female deer during the "normal" breeding period, nor did treated females return to normal ovarian function and exhibit reproductive behaviors during the post-breeding period. This prolonged-release leuprolide formulation offers an alternative approach to reversible contraception in female deer that overcomes some of the problems associated with existing technology.

Animals↗
PubMed1985

The influence of an essential fatty acid deficient-diet on the reproductive performance of female rats.

Several parameters of the reproductive function were studied in albino rats of the Wistar strain fed an essential fatty acid-deficient (EFAD) diet, a linoleic acid-sufficient (EFAS) diet or a commercial diet (CD). The frequency of irregular estrous cycles, with an increased incidence of prolonged diestrus, was significantly higher in EFAD and EFAS groups than in the CD group. There were no significant differences between EFAD and EFAS rats in any of the estrous cycle parameters studied. The EFAD rats showed the following changes in reproductive performance in respect to EFAS and CD dams: prolonged period of gestation, reduced litter size and increased pup mortality during delivery and the first 48 neonatal hours. From this time to weaning, EFAD and EFAS pups had a similar rate of mortality and were different in this respect from the CD group. These results support previous reports indicating that linoleic acid is essential to the maintenance of normal pregnancy and the survival of newborn rats. Nevertheless, we cannot conclude that impairment of the estrous cycle and sucking mortality until weaning were primarily due to the absence of linoleic acid in the maternal diet. The possible role of alpha-linolenic acid in the reproductive is discussed.

Animals↗
PubMed2003

[Study on sperm quality of the soldiers influenced by reinforced training].

OBJECTIVES: To investigate the correlation between abnormal sperm parameters and reproductive hormones and reinforced training. METHODS: Epidemic investigation were done between two different groups by determining endocrine hormone and standard clinical sperm analysis. RESULTS: Comparison between reinforced training group and non-training group showed decreased sperm velocity but no change on sperm moving form, increased teratism sperm percentage but no change on sperm number, decreased plasma testosterone but no change on LH. CONCLUSIONS: Reinforced training has correlation with weak part of sperm parameter analysis and reproductive hormones.

Humans↗
PubMed2006

Investigations on reproductive physiology in the male Eurasian lynx (Lynx lynx).

This study characterized (in vivo) morphological and functional parameters of reproductive organs of adult male lynx (n = 3) prior to, during, and after the breeding season (n = 3). Size and morphology of the reproductive tract were monitored by transcutaneous (testes) and transrectal (accessory sex glands) ultrasonography. Semen was collected by electroejaculation. Ejaculate volume, sperm number, motility, and morphology of spermatozoa as well as testosterone concentrations in blood serum and feces were evaluated. The testes and prostate had seasonal changes in size and echotexture. The mean (+/- S.D.) maximum and minimum testicular volume were 2.8 +/- 0.8 cm3 and 1.5 +/- 0.3 cm3, respectively. Fecal testosterone concentrations were highest in February (1240 +/- 393 ng/g feces), with a second increase in May (971 +/- 202 ng/g feces), but concentrations were lowest in January (481 +/- 52.9 ng/g feces). Ejaculate volume, total sperm number and percentage of motile, and intact spermatozoa were maximal in March (the middle of the breeding season). In one of the eight litters, multiple paternity was proven; however, in the remaining seven litters, all 16 cubs were sired by the same male. This particular male had the most developed and active testes and best semen quality, which may be important for sperm competition.

Animals↗
PubMed2002

The geographical and temporal evolution of sexually transmitted disease epidemics.

In developing appropriate interventions to control sexually transmitted infections (STIs) it is important to understand the distribution of infections, and how this distribution is influenced by the dynamic nature of epidemics. The epidemiology of STIs has been described as a series of phases, which loosely positions a population within the history of an epidemic. The relation between a mathematical theory describing STI epidemiology and the taxonomy of "phases" is explored in this review of the transmission dynamics of STIs. The likelihood of spread and persistence of infection depends upon the basic reproductive number, whereas the endemic prevalence of infection depends upon the way in which heterogeneity in risk focuses the density dependent constraints limiting the spread of infection. All interventions aimed at reducing the prevalence and incidence of infection must act through the reproductive number. The key parameters determining the reproductive number and the relevance of risk behaviours depend upon the biology of the particular infection. The division between high transmission probability, short duration infections and low transmission probability, long duration infections is explored.

Disease Outbreaks↗
PubMed1989

Age-related differences in the sensitivity to opiate-induced perturbations in reproductive endocrinology in the developing and adult male rat.

The effects of a single morphine pellet (75 mg) implanted in developing male rats at 27 days of age on reproductive endocrine parameters were compared to those found in adult (65-day-old) animals after the same treatment. The pellets were left in place to provide the release of morphine during critical phases of puberty and sexual maturation and to prevent an abrupt withdrawal syndrome upon pellet removal which would confound our results. Developing rats were sacrificed at representative intervals after pellet insertion to assess the development of key indices of reproductive endocrinology; adult rats were sacrificed at the same time intervals to permit an evaluation of age-related differences in the sensitivity to opiate-induced endocrine disturbances. Our results showed that morphine markedly influenced a number of endocrine parameters associated with the maturation of the hypothalamic-pituitary-gonadal axis in developing rats for prolonged periods of time, whereas the effects of the opiate in the adult rat were relatively modest and transient. In the developing rat, serum luteinizing hormone (LH), testosterone, the wet tissue weights of the seminal vesicles and testes and hypothalamic LH-releasing hormone (LHRH) levels were substantially depressed immediately after pellet implantation and these effects persisted for up to 4 weeks when compared to placebo-implanted, age-matched controls. In contrast to these results, adult rats showed only transient effects (less than 1 week) of morphine on certain reproductive endocrine parameters (e.g., serum LH, testosterone and the weights of the seminal vesicles) and no effects on others (e.g., testes weights and hypothalamic LHRH).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed2001

Response of animals to dietary gramine. II. Effects of feeding high-gramine yellow lupin seeds on reproductive performance of rats and on selected hematological and biochemical parameters in offspring.

Two groups of 26 male and 26 female rats at the initial age 30 +/- 2 days were fed during 31 weeks on diets containing 20 percent of yellow lupin seeds having low (LG) or high (HG) gramine content. The animals were mated twice within nutritional groups, 1 male: 1 female, and their main reproductive parameters were recorded. In both reproductive cycles body weight of females at mating, after parturition and after 21-days lactation was lower in HG than in LG group. Fertility rate and body weight of neonates were not affected by the diet while number of neonates per litter tended to be lower by 0.7 and 0.8 pups in HG than in LG group. Body weight of weaners was also substantially smaller in dams fed on HG than LG diet. Relative weight of spleen but not of liver, kidney and heart was significantly greater in HG females. Four weeks old males and females issued from the first litters born to LG and HG animals (ten males and ten females per treatment) were fed individually on respective diets during 3 weeks. Feed intake and growth rate did not differ between the treatments. In males relative weight of liver and testicles was greater, while hematocrit and red blood count were lower in HG than in LG group. In females organ weights did not differ. Activity of liver enzymes determined in males was not affected by the diet. It may be concluded that high-gramine lupin affects negatively lactational performance, probably via lower feed intake, but it does not induce apparent teratogenic effects in the progeny.

Alkaloids↗