The reproductive response to the male effect of 7- or 10-month-old female goats is improved when photostimulated males are used

The exposure of adult, female, Mediterranean goats during anoestrus to males with induced sexual activity via photostimulation, induces a very high percentage of ovulations. The present work examines the ability of photostimulated bucks to improve the male effect-induced reproductive response of young does over that induced by non-stimulated bucks. A 2×2 factorial experiment was designed, consisting of doe age and buck photoperiod treatments. During seasonal anoestrus, 41 does aged 7 (n=19) or 10 (n=22) months were subjected to the male effect on 10 April; half of each group was exposed to males rendered sexually active by prior exposure to 3 months of long days (16 h of light/day) from 31 October (PHOTO bucks), and half to males maintained under the natural photoperiod (CONTROL bucks). Oestrous activity was recorded daily by direct visual observation of the marks left by male-worn marking harnesses over the 32 days following the bringing of the sexes together (introduction). Doe body weight and body condition were determined weekly. Ovulation was detected by measuring plasma progesterone concentrations twice per week over the 3 weeks after introduction. The ovulation rate was assessed by transrectal ultrasonography. Fecundity, fertility, prolificacy and productivity were also determined. The interaction doe age × buck photoperiod treatment had no effect on any outcome. The percentage of females showing ovulation or oestrus was higher in the does exposed to PHOTO bucks (85% v. 43% for those exposed to CONTROL bucks) they also showed higher fertility (75% v. 43%) and productivity (1.05±0.17 v. 0.57±0.16 kids born per doe serviced) (all P values at least P<0.05). The 10-month-old group showed higher percentage of females showing ovulation, oestrus, fertility and productivity than the 7-month-old does after the male effect (females showing ovulation: 82% v. 42%; showing oestrus: 73% v. 42%; fertility: 73% v. 42% and productivity: 1.09±0.17 v. 0.47±0.14 goat kids born per doe serviced; respectively, all P values at least P<0.05). The present results show that the use of photostimulated males improves the reproductive performance of 7- and 10-month-old does, and may contribute towards increasing their productivity and lifetime reproductive performance.     

Seminal plasma and male factor signalling in the female reproductive tract

In mammals, insemination results in the transmission of seminal factors that act, in the female reproductive tract, to promote sperm survival, to “condition” the female immune response to tolerate the conceptus and to organise molecular and cellular changes in the endometrium to facilitate embryo development and implantation. These events are initiated when signalling agents, including transforming growth factor-β and other cytokines and prostaglandins secreted by seminal vesicle and prostate glands, interact with epithelial cells in the cervix and uterus to activate cytokine synthesis and to induce cellular and molecular changes resembling a classical inflammatory cascade. The consequences are the recruitment and activation of macrophages, granulocytes and dendritic cells, which have immune-regulatory and tissue-remodelling roles that culminate in improved endometrial receptivity to the implanting embryo. Cytokines elicited by seminal activation have embryotrophic properties and also contribute directly to the optimal development of the early embryo. This review summarises our current understanding of the physiology of responses to seminal plasma in the female reproductive tract and considers the evolutionary significance of seminal plasma in influencing female tissues to promote the success of pregnancy.The author acknowledges the support of the NHMRC of Australia Fellowship and Program Grant schemes.     

Use of gonadotropin releasing hormone to improve reproductive responses of ewes introduced to rams during seasonal anestrus

Three experiments were conducted on anestrous ewes of Suffolk, Dorset, and Katahdin breeding to examine the potential value of GnRH to improve ovulation and pregnancy in response to introduction of rams. In Experiment 1, treatment with GnRH 2 d after treatment with progesterone (P₄; 25 mg i.m.) at introduction of rams was compared to treatment with P₄ alone at the time of introduction of rams. Treatment with GnRH did not increase percentages of ewes with a corpus luteum (CL) 14 d after introduction of rams, pregnant 32 d after treatment with PGF₂α 14 d after introduction of rams, or percent of treated ewes lambing to all services. In Experiment 2, treatments with GnRH on day 2, 7, or both after introduction of rams were compared. Treatments did not differ in mean estrous response, percentages of ewes with a detectable CL or number of CL present on day 11, or mean pregnancy and lambing rates. Therefore, neither one nor two injections of GnRH at these times appeared to be effective to induce anestrous ewes to breed. In Experiment 3, treatments compared included GnRH 4 d before introduction of rams, GnRH 4 d before and 1 d after introduction of rams, ram introduction alone, and treatment with P₄ (25 mg i.m.) at the time of introduction of rams. Percentages of ewes with concentrations of P₄ greater than 1 ng/mL (indicating formation of CL had occurred) 7 d after ram introduction tended to be greater (P < 0.07) in ewes treated with GnRH or P₄ than in control ewes treated with ram introduction alone. However, there was no difference in P₄ concentrations between groups by day 11 or 12 after introduction of rams. Estrous response rates and percentages of ewes pregnant 95 d after PGF₂α was administered (on day 12 after introduction of rams) tended to be greater (P = 0.08 and 0.06, respectively) in ewes treated with GnRH or P₄ than in ewes exposed to rams only. There was no difference in response variables between ewes treated with GnRH 4 d before introduction of rams and ewes treated with GnRH 4 d before and 1 d after introduction of rams. In conclusion, treatment with GnRH 4 d before ram introduction showed promise as an alternative to treatment with P₄ to improve the ovulatory response and reproductive performance of ewes introduced to rams during seasonal anestrus.     

Nutritional status influences reproductive seasonality in Creole goats: 1. Ovarian activity during seasonal reproductive transitions

The objective was to determine the effect of body energy stores, evaluated by a body mass index (BMI), and food intake (FI), on the length of the anovulatory period and ovarian activity during the seasonal reproductive transitions in Creole goats. Non-pregnant, non-lactating Creole goats (n = 28) were fed to induce two different BMI conditions: Greater (GBMI; n = 15), and Lesser (LBMI; n = 13). Each BMI group was divided into two sub-groups, which were either feed restricted (FR) or non-feed restricted (NFR). Goats in the NFR groups received a diet containing 100% of the daily maintenance requirements (basal diet), while restricted goats were subjected to alternated periods, receiving 100% (11 d) and 60% (10 d) of the basal diet, during the entire experimental period. The experiment started after does were treated to synchronize time of estrus. Serum progesterone was determined in samples obtained twice a week, and used as a criterion for determining ovulations. During the transition to the anovulatory period three transrectal ovarian ultrasonographic scans were performed in a sub-group of 12 goats (n = 3 for each treatment combination). The diameter of the largest follicle (LFD) and the total number of antral follicles ≥2 mm (TAF) were recorded. Ultrasonographic ovarian scans were performed at 21, 42 and 63 days after the beginning of the experiment, concurrently with the end of each feed restriction period. The variables of response associated with ovulation were not influenced by BMI or BMI × FI interaction. However, FI influenced length of anovulatory season, as the anovulatory period was 30 d longer (P < 0.05) in the FR group as compared with the NFR group. Independently of treatments, TAF and LFD decreased from the first to the third ultrasonographic ovarian scan (13.2, 10.8 and 4.4 follicles; 3.7, 2.7 and 2.3 mm). Nevertheless, in PER 1 the number of TAF was greater (P < 0.05) in the FR as compared with NFR group and the GBMI group had a larger LFD (P < 0.05) as compared to the LBMI group. It is concluded, that temporal restriction in feed intake could affect the time of cessation and initiation of ovulations during the periods of transition to seasonal anestrus and return to estrous activity, and increase the length of the anovulatory period. In addition, ovarian follicular development during transition into the anovulatory period is differentially influenced by food intake and the status of body energy stores.     

Male achromatic wing colouration is related to body condition and female reproductive investment in a dichromatic species,the upland goose

In many bird species, achromatic plumage patch size can serve as a male status signal, but the use of variations in the achromatic colours themselves as a quality signal has only recently come into focus. In our study, we sought to determine whether achromatic plumage reflects individual quality in the upland goose (Chloephaga picta leucoptera). We examined the relationship between male head and wing reflectance, male condition and female reproductive investment. We found that males with darker specula and greater contrast between the white wing coverts and the speculum were in a better body condition. Variations in the brightness of the white plumage were not a quality signal in the upland goose. The information gleaned from the wing colouration of male upland geese could be used during mate selection, when females choose their mate on the basis of the outcomes of aggressive encounters. During these fights, the males expose their white coverts and their specula, which are normally tucked beneath body feathers.     

Body condition during pregnancy and lactation and reproductive efficiency of mares

In Experiment I, 32 mares were equally allotted to the following treatments: mares fed to A) high body condition from 90 days prepartum to foaling and maintained in high body condition to 90 days postpartum, B) high body condition from 90 days prepartum to foaling and allowed to lose body condition to 90 days postpartum, C) lose body condition from 90 days prepartum to foaling and maintained in low body condition to 90 days postpartum, and D) lose body condition from 90 days prepartum to foaling and allowed to gain weight after foaling to attain a high level of body condition by 90 days postpartum. After three cycles, pregnancy rate at 30 days postovulation was lower (P<0.05) in C mares (50%) than in those in the other three groups (100%). Maintenance of pregnancy to 90 days was also reduced (P<0.05) in C mares (25%) when compared with A, D (both 100%) and B mares (88%). Foal growth to 90 days of age was similar in all treatments. In Experiment II, 927 mares were evaluated for body condition and monitored for reproductive performance. Pregnancy rate was lower (P<0.05) and number of cycles/conception was higher (P<0.05) for barren and maiden mares entering the breeding season in thin condition and for pregnant mares foaling in thin condition (condition score less than 5.0) when compared with mares with a higher level of condition. Also, onset of estrus and ovulation appeared to be delayed in barren and maiden mares entering the breeding season in thin condition. Breeding efficiency was enhanced in mares entering the breeding season or foaling at a condition of 5.0 or above. Initial excess stores of body fat enhanced fertility. There were no detrimental effects of excess body fat stored in late gestation.     

Changes in female reproductive condition following male take-overs in a colony of hamadryas and hybrid baboons

This paper describes and discusses events observed in the Madrid colony of hamadryas and hybrid baboons, when a novel group of 3 adult males, 3 adult females and 1 unweaned infant was introduced to the resident colony comprising 12 adult females, 11 juveniles and 6 unweaned infants. Novel males took over resident adult females in any reproductive condition, and all acyclic females (i.e. lactating, pregnant and immature) exhibited a dramatic enhancement of sexual activity. Lactating females shortened their postpartum amenorrhoea periods and resumed oestrous cycles around day 14 following the introduction of the novel males, without infanticide occurring. Their return to breeding condition was not affected by the age of their current infant or the day they were taken over by the males. A female in an early stage of pregnancy aborted spontaneously and resumed oestrus on day 26. The other pregnant female significantly shortened her gestation time, delivered a viable infant on day 13, and resumed breeding activity 39 days post-partum (on day 52), while suckling her infant. A cycling female adopted and suckled a 74-day-old infant, continued showing oestrous cycles and conceived. Immature females reached menarche significantly earlier than expected and only then joined one of the newly established harem units. It is argued that the observed enhancement of sexual activity was not imposed by the males' aggressive behaviour but rather was a spontaneous female response to male novelty. This single causal factor was potent enough to override the role that nutrition and lactation normally play in the control of the females' reproductive activity. Differences in latency until the appearance of the response were probably due to the different constraints imposed by the female's current reproductive state. It was also hypothesized that when (a) sexual swellings are attractive to males, (b) novel males are especially active in the process of bonding with new females, and (c) males are important sources of coalitionary support, females might by developing sexual swellings compete more successfully against other females and attain a higher position in the female hierarchy of the newly established unit. This would have the ultimate effect of increasing their potential reproductive success. In several cases females did gain socially by coming into oestrus, but attained no immediate reproductive advantage.     

Induction of estrus with intramuscular injections of GnRH or PMSG in lactating goats (Capra hircus ) primed with a progestagen during seasonal anestrus

In Experiment 1, goats in seasonal anestrus (n=154) were treated with sponges impregnated with 1 of 2 types of progestagen (MAP or FGA) followed by PMSG (400 IU im) 48 h before sponge removal. The type of progestagen used had no effect on kidding, abortion, pseudogestation, multiple births, stillbirths, number of live births per doe or gestation length. In Experiment 2, lactating goats (n=24) in seasonal anestrus were treated with progestagen sponges (MAP). At sponge removal they received one of the following treatments: 1 injection of PMSG (400 IU im), 1 injection of GnRH (125 mug im; GnRH-1), or 2 injections of GnRH (125 mug/injection im; GnRH-2) at a 48 h interval. Serum samples were taken at 6-h intervals for 96 h, starting 12 h after sponge removal. Heterologous radioimmunoassays were validated for the measurements of goat FSH, LH, E(2) and P(4). The onset of estrus (P=0.004), mean doe receptivity (P=0.0006), maximum preovulatory E(2) concentrations (P=0.0001) and LH peak concentrations (P=0.08) occurred significantly later for GnRH-1 and GnRH-2 than for PMSG treatment. The PMSG treatment induced a preovulatory LH peak in a greater number of goats (P=0.05) and gave a higher gestation rate than GnRH-1 and GnRH-2 treatments (57 vs 0 vs 12%; P=0.03). It is likely that the GnRH treatments administered did not reactivate the hypothalamo-pituitary-gonadal axis. Thus, intramuscular injections of GnRH in lactating goats primed with a progestagen were not as effective in regulating reproductive performance during seasonal anestrus as were injections of PMSG.     

Impact of male condition on his spermatophore and consequences for female reproductive performance in the Glanville fritillary butterfly

In butterflies, male reproductive success is highly related to the quality and the size of the spermatophore transferred to the female. The spermatophore is a capsule produced by the male during copulation, which in many species contains sperm in addition to a nuptial gift, and which is digested by the female after copulation. The nuptial gift may contribute to egg production and offspring quality, and in some cases also to female body maintenance. The production of the spermatophore, however, represents a cost for the male and, in polyandrous species, ejaculates are sometimes allocated adaptively across matings. Nonetheless, although the ecological factors affecting the reproductive success of female butterflies have been the topic of numerous studies, little information exists on the factors affecting males’ contribution to reproduction, and the indirect impacts on female fecundity and fitness. We used the Glanville fritillary butterfly, Melitaea cinxia (Linnaeus, 1758) (Nymphalidae), in order to assess variation in male allocation to matings. In this species, smaller males produce smaller spermatophores, but variation in spermatophore size is not correlated with female reproductive success. We show that spermatophore size increases with male age at first mating, decreases with mating frequency and adult food‐deprivation, and is not influenced by developmental food‐limitation. The length of copulation period does not influence the spermatophore size nor influences the polyandrous mating behavior in this species. Male contribution to his spermatophore size is clearly influenced by his condition and adult‐resource at the time of mating. Despite this variation, spermatophore size does not seem to have a direct impact on female reproductive output or mating behavior.     

The effect of melatonin implants during the seasonal anestrus on embryo production after superovulation in aged high-prolificacy Rasa Aragonesa ewes

The aim of this study was to assess the effect of melatonin implants administered in March on the ovarian cyclicity, ovulatory response and embryo production after repeated superovulation of selected high-prolificacy Rasa Aragonesa aged ewes. During the seasonal anestrus of two consecutive years, 113 superovulatory treatments have been performed. Ewes were treated (M) or not (C) with melatonin implants in March (day 0). All of them received intravaginal progestogen sponges on day 24 (recovery 1) and 80 (recovery 2) after melatonin implants insertion in year 1, and on day 28 and 77 in year 2. The intravaginal sponges were removed after 14 days. Superovulatory treatments consisted of eight doses in decreasing concentrations (2 mL x 2 and 1 mL x 6) of oFSH (Ovagen) administered twice daily starting 72 h before sponge removal. Seven days after the onset of estrus, embryos were recovered by laparotomy. Melatonin increased cyclicity only in recovery 2 year 2 (83% versus 42%; P < 0.05) but not in the other experimental periods. Among the 78% (88) ewes that ovulated and produced functional corpora lutea, melatonin implants tended to improve embryo viability in recovery 2 by increasing the number of blastocysts per superovulatory treatment (2.4 +/- 0.6 versus 1.1 +/- 0.4; P = 0.09), the rate of viability (67 +/- 9% versus 43 +/- 9%; P < 0.05), and freezability (55 +/- 9% versus 33 +/- 8%; P < 0.05). More specifically, melatonin induced a significant reduction of the number and rate of non-viable (degenerate and retarded) embryos in recovery 2 (0.4+/-0.1 embryos versus 1.3 +/- 0.3 embryos and 4 +/- 1% versus 22 +/- 6%, respectively; P < 0.05). Our results demonstrate that melatonin implants in March can improve at medium term (3 months after implantation) the viability of embryos collected from selected high-prolificacy Rasa Aragonesa aged ewes after superovulation.     

Modulation by neonatal thymectomy of the reproductive axis in male and female rats during development

The effects of neonatal thymectomy, at 3 days of age, on parameters of the reproductive axis were examined in male and female Sprague-Dawley rats. Gonadal and accessory sex tissue (male: epididymis, seminal vesicle, and ventral prostate; female: uterus) weights as well as anterior pituitary, spleen, and adrenal weights were determined in the thymectomized and sham-thymectomized animals at 20, 30, 40, 50, 60, and 90 days of age. Plasma gonadotropin concentrations as well as pituitary content of the gonadotropins and prolactin were assessed at each of these time intervals. No significant difference in gonad and accessory sex tissue weights was detected in thymectomized versus sham-operated controls at each of these times. Adrenal weights were increased in thymectomized animals compared with controls at 50 days of age and older in male rats and at 90 days in females. Spleen weights were decreased in the thymectomized males at 50 and 60 days of age. Thymectomy did not affect the spleen weight of females. Plasma concentrations of gonadotropins were unaffected in thymectomized males but were altered in females during the pre- and peripubertal period (Days 20-40). Vaginal opening, however, occurred at the same time in the thymectomized and control females. Pituitary gonadotropin and prolactin content were unaffected by thymectomy of the females, except at 90 days when pituitary luteinizing hormone (LH) content was lower in thymectomized than in control animals. LH and prolactin content were significantly reduced in the males at 60 and 90 days of age. These results demonstrate that there are sexual differences in the effects of thymectomy on parameters of the reproductive axis.(ABSTRACT TRUNCATED AT 250 WORDS)     

The ovulation rate in anoestrous female goats managed under grazing conditions and exposed to the male effect is increased by nutritional supplementation

This experiment was conducted to determine if feed supplementation before exposure of anoestrous does to males increases ovulation rate. Does (n=50) grazing natural vegetation were divided into two groups (n=25). One group received no feed supplementation, while the other was supplemented daily, with a mixture of 950 g of alfalfa hay, 290 g of rolled corn and 140 g of soy bean per animal for 7 days before exposure to bucks. On April 7, all females were exposed to four adult sexually active bucks (two per group) for 15 days. The ovulation rate at the ovulation detected within 5 days of exposure to males, assessed by transrectal ultrasonography, was greater (P<0.05) in supplemented (1.6+/-0.2) than in non-supplemented females (1.0+/-0.2). In contrast, ovulation rate at the subsequent ovulation, detected between days 6 and 15 of contact with males, was not different (P>0.05) between supplemented (1.3+/-0.1) and non-supplemented females (1.3+/-0.2). Feed supplementation 7 days before exposure to sexually active bucks of females managed under grazing conditions increased their ovulation rate at the first male-induced ovulation but the stimulatory effect of supplementation did not persist and was not observed at the subsequent ovulation.     

Maturation of mosquito spermatozoa during their transit throughout the male and female reproductive systems

The testes, seminal vesicles and spermathecae of 22 species of mosquitoes belonging to the genera Aedes, Anopheles, Culex, Mansonia and Toxorhynchites are investigated under the electron microscope. Modifications of the acrosome and sperm wall occur during the transit of the spermatozoon from the lower region of the testes to the spermathecae throughout the seminal vesicles. The origin and fate of the cell coat and the possible roles of somatic cell layers both in the testes and the seminal vesicles are discussed.     

Parity of female goats does not influence their estrous and ovulatory responses to the male effect

The objective of the present study was to determine whether parity is a factor that influences the estrous and ovulatory responses of female goats when they are stimulated by males that show increased sexual activity. To stimulate sexual activity, four adult male goats were subjected to photoperiodic treatment for 2.5 months comprising long days, with the treatment commencing on 1 November. On 14 April at 1900 h, a group of multiparous females (n = 21) and a group of 16 months-old nulliparous females (n = 19) were exposed to four bucks (two per group) for 15 days. Throughout the study period, the estrous behavior of these female goats was detected twice on a daily basis. Ovulations of the female goats were determined by ecography on days 7 and 18 after exposure to males. The sexual behavior of males was recorded twice every day from 0800 to 0900 h and from 1730 to 1830 h during the first 4 days after introduction in the pen of females. The total cumulative proportion of multiparous females that had ovulations (100%) and displayed estrous behavior (100%) during the 15 days of exposure to males did not differ (P > 0.05) from that of nulliparous females (100% and 95%, respectively). The interval between introduction of males and onset of estrous behavior did not differ (P > 0.05) between multiparous (1.9 ± 0.1 days) and nulliparous (1.7 ± 0.2 days) females. The proportion of females displaying a short estrous cycle was greater (P < 0.05) in multiparous (13/21, 62%) than in nulliparous (5/19, 26%) females. Duration of these shorter than typical estrous cycles did not differ (P > 0.05) between groups (multiparous: 5.2 ± 0.3 days, nulliparous: 4.5 ± 0.1 days). The number of anogenital sniffings was greater (P < 0.001) in males exposed to nulliparous than in those exposed to multiparous females. In contrast, the number of mounting attempts was greater (P < 0.01) in males that were introduced to multiparous than in those that were introduced to nulliparous does. The number of flehmen, nudging, self-marking with urine, and mounts was not different (P > 0.05) between males that were in contact with multiparous and nulliparous females. These results indicate that regardless of parity, female goats respond to male introduction if they are stimulated by males that were previously exposed to artificial long days to increase their sexual behavior.     

Male reproductive effect of arsenic in mice

Arsenic, a known human carcinogen, was given to mice via drinking water as sodium arsenite at a dose 53.39, 133.47, 266.95 and 533.90 mol l for 35 days. A decrease in the activity of 17 HSD along with increase in LDH, GT activity were observed at 533.90 mol l. The observed sperm count, motility and morphological abnormalities in sperm were similar to control at lower dose levels. However at 533.90 mol l a significant decrease in sperm count and motility along with increase in abnormal sperm were noticed. Significant accumulation of arsenic in testes and accessory sex organs may be attributed to the arsenic binding to the tissues or greater cellular uptake. No effects were observed on indices studied for reproductive effects at 53.39 mol l arsenic close to which human being are exposed through drinking water under the present set of experimental conditions.     

Male and female reproductive phenology and annual production of male cones in two natural populations of Cedrus deodara

Phenology of reproductive cones, microsporangium dehiscence and pollen production were studied in natural populations of Cedrus deodara at two different locations, the warmer Khirsu (1800  m a.s.l.) and the cooler Teka (1900  m a.s.l.) in the Pauri forest division of Garhwal Himalaya, India. The reproductive phenophases (cone bud initiation to pollination) goes up to four months with a blooming and pollination period of one month. The prolonged period of male cones during the immature phase was due to two months dormancy, and the dormancy, in turn, could be due to high precipitation during this phase. The pattern of opening of male cones was basipetal succession. Microsporangium dehiscence was dependent on air temperature and relative air humidity with a peak between noon and 2  pm. Flowering shows a high level of asynchrony among individuals within the population, leading to a possibility for geitonogamous selfing. Annual production of male cones varies greatly from one year to the next. A reduced number of pollen cones per tree in 2001 resulted in a decline in overall annual pollen production. In conclusion, the results revealed that the production of male cones represent only one factor that substantially influences the mating system, which will interact with the flowering phenology to influence the genetic composition of the population.