Frequent semen collection and sperm reserves of the male Angora goat (Capra hircus).

Semen was collected from six mature and sexually rested Angora bucks at one-hour intervals five times a day on each of 5 consecutive days in the breeding season. There was a marked decline in semen volume (P less than 0.001), sperm concentration (P less than 0.05) and number of spermatozoa (P less than 0.001) on consecutive days. Successive ejaculates within days differed only in number of spermatozoa (P less than 0.001). The following year at the beginning of the breeding season, the weights of testes and epididymides and the reserves of spermatozoa in these parts were examined after slaughter of the six bucks. The mean number of spermatozoa in the paired testes, capita, corpora and caudae of the epididymides were (22.8 +/- 1.24) x 10(9), (9.4 +/- 1.19) x 10(9), (3.4 +/- 0.22) x 10(9) and (35.0 +/- 2.21) x 10(9), respectively. Epididymal reserves of spermatozoa were correlated with testicular weight (r = 0.50, P = 0.01) and number of spermatozoa in the testes (r = 0.42, P = 0.07), but not with epididymal weight. The daily production of spermatozoa per animal in the breeding season was estimated to be 4.0-6.4 x 10(9).     

Copulation exposes female Red-winged Blackbirds to bacteria in male semen

One often cited but poorly studied cost of multiple mating by female birds is the risk of acquiring sexually transmitted pathogens. We examined the ejaculates of male Red-winged Blackbirds Agelaius phoeniceus to determine if exposure to bacteria from males was a potential consequence of copulation for females. Ejaculates were collected in the field using a model female fitted with a sterile artificial cloaca. We found that 11 of 18 sampled males left ejaculates containing bacteria (compared to 3 of 18 control swabs of a sterile cloaca similarly exposed to the environment). We could identify to species or genus 13 of 26 isolates of bacteria from ejaculates, and found that each male left a unique combination of types. Only three types were found in more than one male (one additional male in each case). We found no qualitative effects of bacterial contamination on male fertility or female reproductive success, but larger sample sizes would be needed for a quantitative analysis. Little information is available on how the strains we identified might affect birds, but several types have known debilitating effects in humans or domesticated mammals. Two bacterial types isolated from blackbird semen are reported to produce chitinase, an enzyme with possibly beneficial consequences if produced by bacteria entering the gut of an insect-eating bird. These results suggest that exposure to new bacterial types is a consequence of extra-pair copulations to females. This exposure could have beneficial and/or detrimental effects on female fitness.     

Effect of antioxidants on microscopic semen parameters,lipid peroxidation and antioxidant activities in Angora goat semen following cryopreservation

The aim of this study was to determine the effects of the antioxidants glutamine and hyaluronan and the inclusion of different levels on microscopic semen parameters, lipid peroxidation and the antioxidant activities following the freeze–thawing of Angora goat semen. Ejaculates collected from three Angora goat bucks, were evaluated and pooled at 37 °C. The semen samples which were diluted with a Tris-based extender containing additives including glutamine (2.5; 5 mM) and hyaluronan (500; 1000 μl/ml), and an extender containing no antioxidants (control) were cooled to 5 °C and frozen in 0.25 ml French straws and stored in liquid nitrogen. Frozen straws were thawed individually (37 °C) for 20 s in a water bath for microscopic evaluation. Freezing extenders supplemented with 2.5 and 5 mM glutamine led to higher sperm motility and hypo-osmotic swelling test (HOST) values, compared to the control (P < 0.05) following the freeze–thawing process. The addition of 500 μl/ml hyaluronan resulted in a higher HOST percentage, compared to the addition of 1000 μl/ml hyaluronan and the control (P < 0.001). No significant difference was recorded in the percentage acrosome and total sperm abnormalities, following supplementation with antioxidants. The addition of antioxidants did not prevent malondialdehyde (MDA) formation, compared to the controls. Antioxidant treatment however decreased (P < 0.01) the superoxide dismutase (SOD) activity. The maintenance of catalase (CAT) activity was demonstrated to be insignificant following addition of antioxidants. Further studies are required to obtain more repeatable results regarding the characterization of the enzymatic and non-enzymatic antioxidant systems in cryopreserved goat sperm.     

Sperm transport in the human female reproductive tract in relation to semen analysis characteristics and time of ovulation

Laparoscopic sperm recovery from the pouch of Douglas and tubal fimbriae was performed in 64 infertile couples. Spermatozoa were recovered from 16/35 couples investigated after AIH, and from 13/29 couples post coitum. The method of insemination had no effect on the result, which was positive in 45.3% of all couples, although AIH did result in significantly larger numbers of peritoneal spermatozoa. The number of peritoneal spermatozoa did not show any direct correlation with the number inseminated, but there were reductions along the tract of 5.83 (+/- 1.4 s.d.) orders of magnitude for total sperm count, and 5.52 (+/- 1.21 s.d.) for the number of motile spermatozoa. Only sperm motility had a significant influence on the success of sperm transport; spermatozoa were recovered from patients with sperm densities as low as 3.0 and 3.5 x 10(6)/ml, but with 56 and 44% motile spermatozoa. No influence of cycle day within the range +/- 4 days of ovulation on sperm transport was found. In 45 couples, routine semen analyses were apparently completely normal, but the incidence of sperm recovery was still only 49% (22/45), suggesting that a failure of sperm transport may have been a significant causative factor in their infertility.     

Inhibition of human chorionic gonadotropin-induced ovulation and steroidogenesis by short-term hyperprolactinemia in female rabbits

To clarify the possible direct effects of hyperprolactinemia on the ovulatory process, we experimentally established hyperprolactinemia in female rabbits with 4 daily injections of sulpiride (SLP) at different doses and induced ovulation with human chorionic gonadotropin (hCG). Plasma levels of prolactin (PRL) were increased significantly before hCG injection in each SLP-treated group compared with the corresponding values for the controls. The ovulation rates at 14 h after hCG were significantly reduced in the 16 and 24 mg/kg/day SLP-treated groups. An inverse correlation (r = -0.74, P less than 0.001) was found between the ovulation rate and the increasing in plasma PRL measured just prior to hCG injection. The increase in peripheral as well as ovarian venous progesterone and 20 alpha-hydroxypregn-4-en-3-one(20 alpha-OHP) at 4 and 14 h after hCG injection in inhibited ovulation groups was much less than in the control group. However, the estradiol, androstenedione and testosterone concentrations were comparable with the control values. These results indicate that hypersecretion of PRL induced by SLP has a direct effect on ovary by inhibiting follicular rupture induced by hCG and this inhibitory effect was partly due to the suppression of progesterone secretion during the course of ovulation. This may be one of the causes leading to hypogonadism during hyperprolactinemia.     

New data on serotoninergic mechanisms in ovulation in the cyclic female rat]

Injection of parachlorophenylalanine on dioestrus II at 18:00 was shown to decrease ovulation frequency in 4-day cyclic female rats. This effect was overcome by either HTP, or oestradiol benzoate, when administered on dioestrus II, at 18:00 and 10:00 - 11:00 respectively. No antiovulatory action of PCPA was observed on prooestrus at 13:00. These results provide support to the specificity of action of serotonin in the control of ovulation in the cyclic rat. They also suggest an interaction of serotonin and oestrogens in this control.     

Reproduction in dairy cattle: Effect of age,cow condition,production level,calving-to-first-service interval and the ‘male’

A study was conducted to determine the effect of various factors on the reproductive performance of approximately 1700 cows in 12 seasonally calving dairy herds in North Western Tasmania. Submission rate (percent of cows submitted for service for the first time in the first 24 days of the mating season) rose from 60% to 97% as cow condition score improved from 3 to 5.5. There was no effect on non-return rates (percent of cows submitted for service for the first time in the first 24 days of mating which did not return to service in the subsequent 21 days), provided condition score was 3.5 or over. Milk fat yield was positively correlated to both submission and non-return rate until milk fat yield exceeded 1.0 kg/day when both fell (from 79% to 71% and from 73% to 38%, respectively). Non-return rate was 46% when the calving-to-first-service interval was less than 40 days after which it rose to a more normal 65%. Submission rates were unaffected by calving-to-first-service interval. There was a significant positive correlation between age and non-return rate, but not between age and submission rate, although submission rate also tended to be higher in older cattle. The proportion of cows having short cycles (less than 18 days) was 18%. In contrast to reports in other species, the presence of the male did not improve oestrous detection or non-return rate of cows in the immediate post-partum period.     

The timing of male reproductive effort relative to female ovulation in a capital breeder

1. In large herbivores, the timing of breeding is important for females to hit peak plant protein levels. For males, the timing of reproductive effort is important to maximize the number of females they can mate during autumn rut in competition with other males. The latter depends on when most females are ovulating, but also on how other males with a different competitive ability are timing use of their capital (fat); it may pay younger males to invest more heavily later when prime aged males are exhausted. 2. Based on estimates of body mass loss, we quantify how much timing (start, peak and end dates) of male reproductive effort during rutting varies depending on male age, density and climate as well as timing of female ovulation. 3. Ovulation in adult females was delayed by 5 days from low to high density, and ovulation was also more synchronous at high density. The starting date of decline in male body mass was only later in yearlings than among other age groups. However, at low density, peak and end dates of rut became increasingly earlier and close to peak female ovulation with increasing age up to 7 years of age. Prime-aged males matched peak effort closely with peak rate of prime-aged female ovulation, while younger males were delayed. This is consistent with the view that younger males have a better chance when the prime-aged males are becoming exhausted. 4. Apart from yearlings, male age groups were synchronized in both the starting, peak and end dates of mass decline at high density. Thus, this partly follows change in female ovulation patterns, but also suggests that competition among males decreased with increasing density due probably to lower intensity of sexual selection. The lowered sexual selection may be due not only to more synchronous female ovulation, but also increasingly female-biased sex ratios and a younger male age structure with increasing density. 5. The onset of rutting is somewhat independent of male age (apart from the youngest males), but the peak and end of rutting effort is dependent strongly upon age, density and peak female ovulation. Male rutting phenology is thus best interpreted as a compromise between hitting peak female ovulation and intensity of sexual selection.     

Action of an ovulation stimulator on the genital function of the female rat]

Effect of cyclofenil on genital function implied organs, is studied in cyclic female rats injected s. cut: 0.5, 5 or 50 mg/kg/day, during 12 days. The treatment increases pituitary, adrenal and uterine weights, decreases ovarian weight, adrenal and ovarien cholesterol. These data suggest that cyclofenil acts directly or undirectly at different levels of hypothalamo-pituitary-genital axis with central inhibition and light peripheral stimulation.     

Aromatization and the induction of male sexual behavior in male, female, and androgenized female hamsters

Eight weeks after gonadectomy male, female, and androgenized [10 μg testosterone propionate (TP), 24 hr after birth] female hamsters were given daily treatment with: 150 μg dihydrotestosterone (DHT), 5 μg estradiol benzoate (EB), 150 μg DHT + 5 μg EB, 150 μg DHT + 1 μg EB, 30 μg DHT + 5 μg EB, 30 μg DHT + 1 μg EB, or the oil vehicle. Treatment of castrated male hamsters with 5 μg EB fully restored mounting but relatively few of these animals intromitted and none ejaculated. Treatment with 150 μg DHT restored all components of male sexual behavior but only in a small proportion of the males. Combined treatment with EB and DHT restored mounts, intromissions, and ejaculations in the majority of the males. Although as little as 30 μg DHT + 1 μg EB restored the full complement of male behavior, the males which received 150 μg DHT + 5 μg EB or 150 μg DHT + 1 μg EB required fewer intromissions to achieve ejaculation than the males which received 30 μg DHT + either dose of EB. The response of the androgenized females was similar to that of the males except that the androgenized females had lower intromission rates and none ejaculated. Relatively few of the nonandrogenized females responded to EB and DHT treatment and those that did mounted only a few times each test. These results demonstrate that both EB and DHT can stimulate male sexual behavior in the hamster and that the sensitivity to EB and DHT for copulatory behavior is determined by early postnatal androgen exposure.     

Effect of freezing extender composition and male line on semen traits and reproductive performance in rabbits

This study was conducted to elucidate the effect of different freezing extenders on two lines selected for hyperprolificacy and longevity (H and LP, respectively). In extender A, dimethyl sulphoxide (Me₂SO) and sucrose were used as cryoprotectants. In extenders B and C, the sucrose was replaced by 20% egg yolk, and in extender C the Me₂SO was substituted by acetamide. Semen was packaged in 0.25 ml plastic straws and cooled at 5°C for 45 min, and then was frozen in liquid nitrogen vapour for 10 min before being plunged into the liquid nitrogen. Thawing was carried out by immersing the straws in a water bath at 50°C for 10 s. Frozen-thawed semen characteristics and reproductive parameters were affected by freezing. Extender C showed significantly lower post-thawing quality traits than any of the three extenders. Acrosome integrity was significantly improved when Me₂SO was used as cryoprotectant. Sucrose replacement by 20% egg yolk had no effect on acrosome integrity but provided significantly lower sperm motility and viability. Freezing extender affected fertility rate, total born, number of implantation sites and gestational losses, obtaining better results when extender A was used. The acrosomal integrity after frozen-thawed process showed a significant correlation with fertility at 12^th day and also at birth, indicating that an increase in acrosomal integrity leads to an increase in both fertilities (12^th day and at birth). A positive correlation between motility of semen and implantation sites was found. The post-thawing quality traits of semen were not affected by the genetic line, although LP line showed higher total born and lower foetal and gestational losses. The findings of this study suggest that freezing extender composition has a significant effect on the success of rabbit sperm for preservation, and when Me₂SO was used as permeable cryoprotectant sucrose provided better protection compared with egg yolk and improved reproductive traits, and, on the other hand, the male genotypes used in the present study had no effect on frozen-thawed sperm parameters but negatively affected some of the reproductive parameters.     

Reproduction in female Hartmann's zebra, Equus zebra hartmannae

Ovaries, fetuses and plasma were collected from zebra mares shot in the Etosha National Park in Namibia between 15 and 25 August 1983. Ovarian weight was affected by reproductive status and most of the non-pregnant mares were anoestrous. The number of follicles varied between individuals and only pro-oestrous/oestrous mares had follicles larger than 20 mm in diameter. The largest follicle in pregnant mares was only 9 mm in diameter. Corpora lutea and corpora albicantia were found in non-pregnant as well as pregnant mares: 4 pregnant mares had only corpora albicantia. The presence of secondary corpora lutea could not be confirmed in any of the pregnant mares. Implantation was estimated to occur at around 73 days of gestation, and most mares (84%) had conceived between November and April. Peripheral concentrations of plasma progesterone during pregnancy varied from 0.5 to 2.4 ng/ml.     

Effects of chronic exposure to soy meal containing diet or soy derived isoflavones supplement on semen production and reproductive system of male rabbits

Soy and derivative diets deliver large doses of isoflavones to human and animals throughout their lifespan, including gestation. Epidemiologic and experimental data suggest that the consumption of soybean containing foods may protect against cardiovascular disease and decrease breast, prostate and endometrial cancer risk. Based on animal and in vitro studies, however, concerns have been raised that consumption of isoflavones may cause potential adverse effects on the reproductive tract and behavior. The aim of this study was to investigate the effects of chronic consumption of a soy meal containing diet or soy isoflavones supplement on the morphology of reproductive organs, semen quality, age that males reached puberty, and sexual behavior of male rabbits. With this purpose, 16 female rabbits were randomly assigned to receive: (1) a soy- and alfalfa-free diet; (2) a soy- and alfalfa-free diet supplemented with 5mg/kg body wt./day of soy isoflavones; (3) a soy- and alfalfa-free diet supplemented with 20mg/kg body wt./day of soy isoflavones; (4) a diet containing 18% of soy meal, throughout the gestation and lactation. After weaning, male offspring received the same diet, which was given to the respective mother. The age that males reached puberty, semen characteristics and sexual behavior were evaluated in these animals. At 33 weeks of age, the reproductive organs were submitted to histological evaluation. Rabbits, which received large amounts of isoflavones (20mg/kg body wt./day) had a lesser food intake, body weight and semen volume. Spermatogenesis, morphology of male genital organs and sexual behavior did not differ significantly from the control group. We conclude that chronic dietary treatment with soy based diet or soy isoflavones have no adverse effects on the observed reproductive patterns of male rabbits.     

Reproduction in the freshwater gastropod,Helisoma: involvement of prostaglandin in egg production

Summary

The introduction of nanogram quantities of prostaglandin E₂ (PGE₂) into the female genital opening of mated animals was found to increase both the number of egg masses produced and the number of eggs per mass. The intrahaemocoelic administration of a thousand-fold higher concentration of PGE₂ was without effect, suggesting an indirect role of prostaglandin(s) in the regulation of egg production.

Prostaglandin (PG) synthetase activity in both the bursa copulatrix and ovotestis varied with the reproductive status. High PG synthetase activity was present in virgin animals, and lower activity was found in mated animals.

Prostaglandins produced by the bursa copulatrix are proposed here to be involved in the production of a matedness factor, which acts upon the brain to initiate or modulate egg production. PG produced by the ovotestis may be involved in ovulation. A model is proposed for the involvement of PG in the regulation of reproduction in Helisoma.