Mating Period Research Articles

The response of grey mouse lemurs to acute caloric restriction before reproduction supports the 'thrifty female hypothesis'.

The 'thrifty female hypothesis' states that females preserve more of their energy reserves during winter than males because of the sex-specific time frame of energy allocation for reproduction. As males reactivate their reproductive axis before the mating period, while females mainly allocate energy during gestation and lactation, we hypothesized that males would have to use shorter torpor bouts and longer periods of normothermic activity to promote spermatogenesis during winter, a period of low food availability. Here, we applied an acute 2week 80% caloric restriction in male and female grey mouse lemurs shortly before the mating period. We found evidence of thriftier phenotypes in wintering females, which performed deeper and longer torpor bouts than males and ultimately lost less body mass. Our results thus support the 'thrifty female hypothesis' in a seasonally breeding primate and reinforce the concept of a sex-biased trade-off in using torpor, which might ultimately benefit reproduction and survival.

Automated long‐term monitoring of RFID‐tagged individuals reveals high hibernaculum site fidelity in Daubenton's bats and Natterer's bats

AbstractIn the temperate zone, many bat species depend on underground sites during the autumn mating period and as hibernacula in winter. Anthropogenic or natural alteration or destruction of a hibernaculum may severely threaten the bats that rely on the site, especially if they are not aware of suitable alternatives. Currently, the rate at which bats visit other hibernacula, or disperse between them, is poorly understood. Here, we studied hibernation site fidelity in two European bat species, Daubenton's bat (Myotis daubentonii) and Natterer's bat (Myotis nattereri), that share hibernacula but differ in their hibernation phenology and mating systems. The activity of over 2500 RFID‐tagged individuals was monitored using an automated recording system at the entrances of three hibernacula over eight full years. Hibernation site fidelity was high in both species, with only 1.6% of Daubenton's bats and 4.1% of Natterer's bats moving between the monitored sites during their lifetimes. Juvenile bats moved more frequently than adults and contrary to our expectations, in Natterer's bats, more females moved between hibernacula than males. Movements almost always occurred during the autumn mating season, and more frequently between neighboring hibernacula than between distant sites. Finally, we also found that individuals rarely explored more than one of the three entrances to a site, despite their close proximity. Taken together, our results suggest that some juvenile bats may explore multiple sites, but that they rarely disperse to other hibernacula as adults. As a result, most individuals are either not aware of alternative sites or do not regularly update this information. We therefore argue that the creation of new underground objects as a mitigation measure may not function as an immediate compensation for the disturbance or the loss of an existing hibernaculum. Instead, the proactive identification and protection of existing hibernacula should be prioritized.

Augmenting interpretation of vaginoscopy observations in cycling bitches with deep learning model

Successful identification of estrum or other stages in a cycling bitch often requires a combination of methods, including assessment of its behavior, exfoliative vaginal cytology, vaginoscopy, and hormonal assays. Vaginoscopy is a handy and inexpensive tool for the assessment of the breeding period. The present study introduces an innovative method for identifying the stages in the estrous cycle of female canines. With a dataset of 210 vaginoscopic images covering four reproductive stages, this approach extracts deep features using the inception v3 and Residual Networks (ResNet) 152 models. Binary gray wolf optimization (BGWO) is applied for feature optimization, and classification is performed with the extreme gradient boosting (XGBoost) algorithm. Both models are compared with the support vector machine (SVM) with the Gaussian and linear kernel, k-nearest neighbor (KNN), and convolutional neural network (CNN), based on performance metrics such as accuracy, specificity, F1 score, sensitivity, precision, matthew correlation coefficient (MCC), and runtime. The outcomes demonstrate the superiority of the deep model of ResNet 152 with XGBoost classifier, achieving an average model accuracy of 90.37%. The method gave a specific accuracy of 90.91%, 96.38%, 88.37%, and 88.24% in predicting the proestrus, estrus, diestrus, and anestrus stages, respectively. When performing deep feature analysis using inception v3 with the same classifiers, the model achieved an accuracy of 89.41%, which is comparable to the results obtained with the ResNet model. The proposed model offers a reliable system for identifying the optimal mating period, providing breeders and veterinarians with an efficient tool to enhance the success of their breeding programs.

Social networks of threatened Chaco tortoises (Chelonoidis chilensis) in the wild

Abstract We studied encounters between Chaco tortoises (Chelonoidis chilensis) that are in a threatened state of conservation in Patagonia, Argentina, which constitutes the southern limit of their geographical distribution. We monitored six individuals during different behavioural periods of the year (mating, nesting, and brumation), recording 24 344 encounters after tagging the animals with GPS tags. Constructing bipartite networks of burrows and tortoises, in addition to their projections, we discovered a spatial clustering of the burrows. Moreover, our research revealed that as tortoises approach the brumation period they use fewer unique burrows, engage in less burrow sharing, and increasingly favour spending time in their preferred burrow. During the mating and nesting periods some burrows are shared, whereas this was not the case during the brumation period. We studied the daily interactions through proximity-based networks, accounting for the daytime encounters during the different annual behavioural periods. We found the highest network density during the mating period, decreasing to zero, as expected, for the brumation period, when tortoises remain in their burrows during both night and day. Male–male interactions were more probable during the post-brumation and mating periods. Moreover, the number of daily encounters after sharing a burrow for a given night was found to be significant, which could be an indication of social behaviour and memory. Performing numerical simulations, we found that the proximity-based network densities were much higher than expected by chance, which could be attributable to individual selection of preferred sites or could be indicative of social behaviour among these threatened reptiles.

Effect of post-mating GnRH or TAK-683 (Kisspeptin analog) treatment on the reproductive performance and serum progesterone concentration in ewes during the non-breeding season

This study was designed to evaluate the effect of post-mating GnRH or TAK-683 (kisspeptin analog) treatment on serum progesterone (P4) concentrations and fertility parameters of ewes during the non-breeding season. One hundred and twenty multiparous, lactating Awassi ewes were used. For estrus synchronization, vaginal sponges containing 60 mg of medroxyprogesterone acetate (MAP) were inserted into the vagina and kept there for nine days. On the day of sponge removal (day 0), 500 IU of eCG and 75 µg of d-cloprostenol were given intramuscularly. Rams were introduced in the flock 24 h after sponge removal and kept with the ewes for 26 days, allowing a second mating period after synchronized estrus. On the fourth day after mating (day 6) the ewes mated by the rams between the 24th and 72nd hours (n = 105) were randomly divided into three groups. Control group (n = 36) received 1 ml of saline solution subcutaneously; GnRH group (n = 34) received 4 μg of buserelin acetate intramuscularly; TAK-683 group (n = 35) received 5 μg of TAK-683 acetate subcutaneously. Blood samples were taken to measure serum P4 concentrations (ng/ml) at sponge insertion and on the 6th, 9th, 12th, 15th, 19th, 35th, and 50th days after sponge removal. Pregnancy diagnosis was conducted via serum P4 concentration measurement on the 19th day and transrectal ultrasonography on days 35 and 50. The results showed that GnRH treatment (4.823 ± 0.238; 2.151 ± 0.272) increased (P<0.05) the mean P4 concentration (ng/ml) in pregnant and non-pregnant ewes during the first mating period compared to Control (3.708 ± 0.207; 1.515 ± 0.164), while TAK-683 treatment (4.457 ± 0.181; 1.967 ± 0.213) was not different between groups. GnRH (58.82 %) and TAK-683 (42.10 %) treatments increased the pregnancy rate in the second mating period in comparison to the Control group (17.39 %) (P<0.05). Cumulative pregnancy and fecundity rates were higher in GnRH (79.41 %; 120.58 %) and TAK-683 (68.57 %; 100.0 %) groups than in the Control group (17.39 %; 58.33 %) (P<0.05). There was no difference in late embryonic loss rate among the groups (P>0.05), whereas early fetal loss rate tended to be lower in the TAK-683 (0 %) and GnRH (0 %) groups than in the Control group (15.38 %) (P=0.07). The total pregnancy loss rate (from day 19 to day 50 post-mating) was lower in GnRH (0 %) and TAK-683 (0 %) groups relative to the Control group (21.42 %) (P<0.05). There were no statistical differences among the groups in terms of the first mating period pregnancy rate, twinning rate, and litter size (P>0.05). As a result, treatment with GnRH and TAK-683 on the fourth day after mating increased fecundity in lactating ewes outside the breeding season by preventing total pregnancy losses (from day 19 to day 50) and increasing second mating pregnancy rates.

Moving to mate? Migration strategy does not predict genetic structure or diversity in bats (Chiroptera)

Abstract How, when, and where animals move during mating periods directs gene-flow patterns across landscapes. Traits associated with movement, such as movement ability and migratory behaviour, are sometimes correlated with population genetic structure, but this relationship depends on where and when mating occurs relative to annual movements. With their wide diversity in behaviours and life-history strategies, bats provide a testing ground for hypotheses about population structure related to migration and mating. We used a global sample of microsatellite data (N = 233 sampling locations from 17 bat species) associated with published studies to examine links between genetic variation and short-distance, long-distance, or non-migratory strategies that also relate to varied mating strategies. The genetic measures we tested were population-specific differentiation, gene diversity, and allelic richness. Using Bayesian models that accounted for phylogenetic distances among species and spatial autocorrelation, we identified no correlations between migration strategy and genetic variation. Our results suggest that hypotheses about genetic structure being mediated by migration might not hold, in general, for bat species. We discuss the need for continued research into the complex association of ecological, biogeographical, and behavioural factors that facilitate gene flow among populations, especially in species with diverse movement patterns.

Performance of The White-Rumped Shama (Copysychus malabaricus) Reproduction by Providing Eurycoma longifolia at The Captivity

This research aims to determine the reproductive capacity of the White-Rumped Shama provided by Eurycoma longifolia in terms of duration of couple introduction or adjustment period, duration of mating period until laying eggs, number of eggs, number of hatched eggs, and number of survived baby animals until 5 days of living. The laboratory experimental method is performed in the White-Rumped Shama captivity in Bogor. Before the treatment, the birds are matched in each bird cage. The White-Rumped Shamas are divided randomly into 2 groups, each of which consists of 5 pairs (5 repetitions). The first group (K1) as a control, male magpie parents were given the treatment of drinking distilled water after fasting for one hour every morning, Group 2 (K2) as the Eurycoma longifolia treatment group, male White-Rumped Shama parents were given the optimal dose of Eurycoma longifolia, 9 mg/100 of the body weight every morning for 5 days which was converted from the results of research on the treatment of giving Eurycoma longifolia to white rats. Statistical analysis of two tailed T test, Levene's test on data between the control group (K1) and the Eurycoma longifolia group (K2) showed that; Behavior: Jumping, flying, perching on the perchs, approaching the female, chirping, singing, crouching while near to the female while making a distinctive chirp, eating and drinking, duration of time until laying eggs in the mating cage (days), number of eggs in the nest (items ). The number of hatched eggs from those hatched (grains), the number of offspring that survived to the age of 5 days (tails), there were no significant differences between the control group (K1) and the Eurycoma longifolia treatment group (K2).

Aspects of the demography of two Podarcis muralis populations in anthropogenic modified habitats in western France, based on a non-invasive sampling method

Urbanisation impacts on both abiotic and biotic characteristics of the environment and is likely to bring new selective pressures on animal species living within these areas. The common European wall lizard Podarcis muralis adapts well to urbanisation and indeed may be described as the archetypical urban lizard. In this paper we investigated some aspects of the demography of two populations of P. muralis from western France, one living in a hedgerow system situated in an agricultural area on the edge of a village and a second in an urban garden. The active year in both populations was from February–March until October–December, the latter in the urban garden where temperatures were higher. Numbers decreased from around June then increased again during September but this varied annually and between populations. Diversity and equality indexes for both populations were high, especially in females, indicating a range of individuals and their frequency of presence. Both populations were therefore stable despite only limited numbers of lizards being present for more than one year. Male lizards with high presence were more frequently seen in the company of females than males that were seen less frequently. Hatchling lizards were seen from June after the spring mating period with a second period of hatchlings appearing during autumn. This supports the notion that females annually deposit two clutches of eggs in the area. Keywords: lizards, Podarcis muralis, demography, western France, non-invasive sampling

Weak males do not work hard: Reproductive investment of deficient male fiddler crabs, Austruca lactea

Abstract In iteroparous animals, it may be adaptive to adjust the amount of reproductive investment based on their current competitive ability. Male fiddler crabs use an enlarged major claw for claw-waving display in the breeding season. Males sometimes lose their claws, but they can regenerate a claw, which is an inferior weapon for male-male fights. Here, we compared the waving frequency between males with a regenerated claw (regenerated males) and with an original claw (original males) to examine the differences in the amount of reproductive investment. Regenerated males showed lower waving frequency than original males, but some regenerate males waved frequently before the optimal mating season where original males waved frequently. These results indicate that individuals with poor fighting ability that have lower chance of acquiring females invested less in waving, and may also have shifted their peak of mating period in order to avoid competition with original males.

Mating-induced Ecdysone in the testis disrupts soma-germline contacts and stem cell cytokinesis.

Germline maintenance relies on adult stem cells to continually replenish lost gametes over a lifetime and respond to external cues altering the demands on the tissue. Mating worsens germline homeostasis over time, yet a negative impact on stem cell behavior has not been explored. Using extended live imaging of the Drosophila testis stem cell niche, we find that short periods of mating in young males disrupts cytokinesis in germline stem cells (GSCs). This defect leads to failure of abscission, preventing release of differentiating cells from the niche. We find that GSC abscission failure is caused by increased Ecdysone hormone signaling induced upon mating, which leads to disrupted somatic encystment of the germline. Abscission failure is rescued by isolating males from females, but recurs with resumption of mating. Importantly, reiterative mating also leads to increased GSC loss, requiring increased restoration of stem cells via symmetric renewal and de-differentiation. Together, these results suggest a model whereby acute mating results in hormonal changes that negatively impact GSC cytokinesis but preserves the stem cell population.

First Report of Stem Borer (Xylotrechus smei) Occurrence on Red Sanders Plantations of Tamil Nadu and Gujarat, India

This communication presents the first documented case of the stem borer Xylotrechus smei (Cerambycidae: Coleoptera) infesting red sanders in Tamil Nadu and Gujarat, India. The pest was detected in red sanders plantations located in Dharmapuri and Tenkasi districts of Tamil Nadu, as well as in Surat, Navsari, and Tapi districts of Gujarat, India, during August 2023. In both regions, young red sanders trees aged between 2 to 16 years were affected, with incidence levels varying from 2.24% to 10.86% in the affected plantations. Signs of infestation include the presence of galleries, bore holes in cut stems, complete drying, and mortality of the trees. Initially, larvae feed on the bark, and as they mature, they tunnel through the cambium and wood, impeding nutrient flow and leading to tree mortality. The larvae's deep tunneling within the wood makes them difficult to eradicate with pesticides. Adult beetles typically emerge in peak numbers during April to May and November to December, coinciding with their mating period and selection of host plants for egg-laying. This report aims to outline the damage caused by the stem borer in red sanders and document ongoing monitoring efforts to support interim management strategies.

Reproductive biology and feeding habit of Coilia dussumieri Valenciennes, 1848 (Actinopteri: Engraulidae): A review

Coilia dussumieri, regularly referred to as the goldspotted grenadier anchovy, is a ray-finned fish species that pertains to the Engraulidae family. Estuaries and maritime waters bordering Bangladesh, Myanmar, and India are home to it. On top of that, it can be found from Thailand south to Java and the Malay Peninsula. Any species' genetic features must be scrutinized in order to govern its population smoothly and figure out whether it is well-suited for culture. Fish biology encompasses a broad spectrum of disciplines, consisting of an in-depth overview of their stature, progression, gonado-somatic index (GSI), prime mating period, and fetal growth. Biology regarding consumption and procreation has been the focus of numerous research efforts in the recent past. The main goal of this review work is to bring together the disparate information, identify the knowledge gaps for additional research on this fish species, and provide aqua culturists with some information for future, more in-depth research on the culture, management, and breeding of Coilia dussumieri.

Season and host-community composition inside roosts may affect host-specificity of bat flies.

Bat flies are one of the most abundant ectoparasites of bats, showing remarkable morphological adaptations to the parasitic habit, while the relationship with their hosts is characterized by a high level of specificity. By collecting bat flies from live hosts, our intention was to elucidate the seasonal differences in bat fly occurrence and to describe factors regulating the level of incipient host specificity. Our results indicate that the prevalence and the intensity of infestation is increasing from spring to autumn for most host species, with significant differences among different fly species. Males showed higher infestation levels than females in autumn, suggesting a non-random host choice by flies, targeting the most active host sex. Bat-bat fly host specificity shows seasonal changes and host choice of bat flies are affected by the seasonal differences in hosts' behavior and ecology, the intensity of infestation and the species composition of the local host community. Nycteribiid bat flies showed lower host specificity in the swarming (boreal autumn) period, with higher prevalence recorded on non-primary hosts. Choosing a non-primary bat host may be an adaptive choice for bat flies in the host's mating period, thus increasing their dispersive ability in a high activity phase of their hosts.

TWO SEXUALLY ACTIVE BUCKS HOUSED WITH FOUR SUCCESSIVE GROUPS OF ANOVULATORY DOES INDUCED HIGH PREGNANCY RATES DURING SEVEN-DAY MATING PERIODS

&lt;p&gt;&lt;strong&gt;Background.&lt;/strong&gt; In seasonally anovulatory goats, sexually active bucks led a high pregnancy rate during a mating period of 36 days. Progesterone priming of does can reduce the length of the mating period while maintaining high fertility by allowing oestrous behaviour at the first male-induced ovulation. &lt;strong&gt;Objective.&lt;/strong&gt; To determine whether high fertilization rates could be achieved by using two sexually active bucks, alternated daily for a period of seven days in four successive groups of does. &lt;strong&gt;Methodology.&lt;/strong&gt; Two control bucks were used only with one group of does (&lt;em&gt;n&lt;/em&gt; = 19), whereas two experimental bucks were successively housed with four groups of does (&lt;em&gt;n&lt;/em&gt; = 18 or 19 each). One of the control and experimental bucks was introduced to their respective groups in the morning and removed 24 h later to rest for 24 h. Immediately after the removal of the first buck, the second buck was placed with the group of does. Each doe was treated with 25 mg of progesterone im 48 h prior to the first introduction of bucks to reduce short ovulatory cycles. &lt;strong&gt;Results.&lt;/strong&gt; In each group, the proportion of does that ovulated was higher than 93%. These proportions did not differ among groups exposed to the control or experimental bucks (&lt;em&gt;P&lt;/em&gt; &amp;gt; 0.05). In each group, the proportion of pregnant does was higher than 78%; proportions did not differ among groups (&lt;em&gt;P&lt;/em&gt; &amp;gt; 0.05). &lt;strong&gt;Implications. &lt;/strong&gt;At farms with few bucks, efficient management of sexually active bucks can yield a high percentage of pregnant females. &lt;strong&gt;Conclusion.&lt;/strong&gt; These results indicate that two sexually active bucks housed with four successive groups of progesterone-treated anovulatory does during a mating period of seven days were able to achieve high pregnancy rates.&lt;/p&gt;&lt;div id="gtx-trans" style="position: absolute; left: -60px; top: -20px;"&gt; &lt;/div&gt;

Utilising male stimulus to improve the reproductive efficiency of 8-month-old nulliparous ewes and adult parous ewes

We tested whether utilising the male effect to stimulate ewes before the mating period can reduce the time to conception following the introduction of entire rams, and increase fertility, prolificacy, and reproductive rate (number of fetuses per 100 ewes exposed to fertile rams). A retrospective analysis was used to analyse records from 59,716 ewes collected over 34 years (1986–2020) from seven genotypes: Border Leicester, Composite (crossbred), Dorset, Merino, Dorset x Polypay, Rambouillet, White Suffolk. The dataset also included nulliparous young ewes (mated at age 8 months) and adult parous ewes. Vasectomized rams were used to stimulate 20,632 ewes before a mating period that lasted 2 or 3 estrous cycles, and the outcomes were compared with those from 39,084 ewes that had not been stimulated. Independently of genotype, utilising the male stimulus advanced the average conception date by 8 days for young ewes (P < 0.0001) and by 1 day for adult ewes (P < 0.0001). The male stimulus also increased the proportion of ewes that conceived in their first cycle by 33 % for young ewes and by 6 % for adult ewes (P < 0.0001). For the cycle of conception, there were significant (P < 0.0001) effects of two interactions: male stimulus x age at mating and male stimulus x live weight at mating. The male stimulus improved fertility in both adult ewes (99.8 % vs 89 %; P < 0.001) and young ewes (77.7 % vs 81.3 %; P < 0.001). The male stimulus increased the number of young ewes (41.9 % vs 11.1 %; P < 0.001) and adult ewes (16.6 % vs 2.7 %; P < 0.001) that conceived multiple fetuses in the first 17 days of the mating period. The reproductive rate was improved by the male stimulus in young ewes (129 % vs 135 %; P < 0.001) but not in adult ewes (120 % vs 122 %; P = 0.12). When all animals for all breeds were included in the analyses, there were improvements in fertility, prolificacy, and reproductive rate as age and live weight increased at mating (P < 0.0001). We conclude that, independently of genotype, utilising the male stimulus before the mating period reduces the time to conception and improves reproductive performance in both young and adult ewes.

Sublethal and Transgenerational Effects of Reduced-Risk Insecticides on Macrolophus basicornis (Hemiptera: Miridae).

Reduced-risk insecticides and mirid predators have been used to control Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) in tomato crops. However, even when causing low mortality to the beneficial insects, these products might cause side effects. This study investigated the sublethal and transgenerational effects of buprofezin, cyantraniliprole, and spiromesifen on Macrolophus basicornis (Stal) (Hemiptera: Miridae). After 72h of exposure of third-instar nymphs and adults to residues on tomato leaves, adult couples were formed and kept in cages with residue-free tomato leaves. The leaves were changed every 48h and the offspring were assessed in 6 different periods. Body size was assessed by measuring the hind-tibia length of adults (F0) from exposed nymphs and in three different offspring groups. None of the insecticide residues caused a reduction on offspring populations or affected the body size of adults in generation F0. Regardless, buprofezin and spiromesifen reduced the tibia length of adults (F1) from exposed nymphs assayed in the third mating period. Cyantraniliprole did not affect any parameter and could be recommended for control of B. tabaci in association with M. basicornis releases. This study may contribute to future field assays of the compatibility of these insecticides with M. basicornis.

Effects of prenatal fish oil supplementation on the development and performance of female kids after weaning.

This study was performed to determine the influence of fish oil, an omega-3 fatty acids source, supplemented to diets of goats throughout all stages of gestation on the growth and milk production of weaned female kids. Eighty German Fawn (75%) x Hair (25%) crossbred goats were randomly assigned to treatment (fish oil, FiO group) and control (Rumen protected fat, RPF group) groups during the first half of pregnancy. Subsequently, the FiO group was further allocated into FiO-FiO and FiO-RPF subgroups and RPF group was further divided into RPF-FiO and RPF-RPF subgroups containing 20 goats in each during the second half of pregnancy. The growth and feed intake of 41 female kids (aged 75.1 ± 6.73 days, with a mean live weight of 11.6 ± 3.00 kg) were recorded for a 98 day post-weaning, In the continuation of the study, live weight changes, milk yield and composition of young female goats from mating to the second month of lactation and the growth of female kids until weaning were studied for a total of 210 days. Maternal nutrition slightly influenced the live weight gain of female kids over a 98-day investigation period (p = 0.070). When growth performance was considered, a higher feed conversion efficiency of female offspring was determined in RPF-FiO (5.52) treatment group compare to female kids in other treatment groups (p = 0.086). However, the maternal feeding system significantly affected live weight in the RPF-FiO treatment group during the mating period (P = 0.054). Concerning the feed intake, maternal nutrition significantly affected the feed intake of female kids (p < 0.01) with the highest feed consumption in the FiO-RPF group. The findings of this study have shown that fish oil enriched diet given to goats during gestation improved daily live weight changes and total live weight gain of female kids despite the initial disadvantage after weaning. At mating time, the live weight of young female goats in the RPF-FiO treatment group, which exhibited the highest feed conversion ratio during the 98-day study, was higher than the remaining treatment groups. Maternal nutrition had no effect on milk yield or milk components in young goats during lactation. Young female goats born to dams in the FiO-RPF group showed better performance than the other groups regarding live weight performance of their offspring on 56th day postpartum.

Reproductive/developmental toxicity screening test of kovir capsules in mice

The present study was performed to gather information on the effects of Kovir capsules on reproductive and developmental parameters in mice according to the OECD guideline for reproductive/developmental toxicity screening test. The test item was administered orally at dose levels of 1.44 and 2.16 capsules/kg body weight/day to male mice from 2 weeks before mating to the end of the 14-day mating period and females from 2 weeks before mating, during mating, gestation, and until the 13th day of lactation. During the study period, clinical signs, body weight, relative organ weight, reproductive and littering results, necropsy results, and histopathological examination of the testicles were examined. No significant differences existed between the relative organ weights of exposed and unexposed males after the 4-week exposure. Photomicrographs of the testis of treated males did not display marked damage compared with untreated males. There were also no treatment-related effects of Kovir on pregnancy rates, the number of implantations, and the live fetuses of females. These results suggested that Kovir capsules at both test doses did not induce reproductive hazards in mature male and female animals. The effects of Kovir on the mean litter size, postnatal mortality, and appearance of developmental markers in pups were not identified.

Early life events associated with first lactation reproductive performance in southwest Victorian pasture-based dairy herds.

This was a prospective cohort study to determine how events from birth until first calving affect reproductive performance in the first lactation in pasture-based dairy herds in Victoria, Australia. Events during the preweaning (0 to 84 days), weaning to first breeding (85 to 473 days) and first breeding to first calving periods (474 to 804 days) were recorded and their association with reproductive performance during the first lactation was quantified. Reproductive performance outcomes included the number of days from first mating start date to first service (MSD-S1) and the number of days from first mating start date to first conception (MSD-CON). Predictors for reproductive performance included: passive transfer status as a calf; season of birth; age and breed of the dam; breed; the presence or absence of dystocia at the time of the heifer's birth; active feeding of colostrum versus being left on the dam for colostrum intake; presence of twinning; the presence or absence of preweaning diarrhoea; preweaning, prepubertal and postpubertal average daily gain; the presence or absence of periparturient disease at first calving; age at first calving; body condition score at first calving; sex of the first-born calf; the presence or absence of a stillborn calf at the first calving and requirement of assistance at first calving. Two Cox proportional hazards regression models were developed: the first for early life event variables associated with MSD-S1 and the second for early life events associated with MSD-CON. Heifers born in autumn and winter had 2.89 (95% CI 1.50 to 5.59, P = 0.002) times and 1.97 (95% CI 1.12 to 3.44, P = 0.018) times the daily hazard of being inseminated compared with heifers born in spring, respectively. For the MSD-S1 analyses heifers that gave birth to a live calf had 1.64 (95% CI 1.14 to 2.36, P = 0.008) times the daily hazard of being inseminated compared with heifers that had a stillborn calf. Increases in weight gain during the first breeding to first calving period by 0.1 kg/day increments increased the daily hazard of first insemination by a factor of 1.10 (95% CI 1.00 to 1.22, P = 0.043). Heifers that experienced periparturient disease had a significantly lower hazard of conception per day compared with heifers that did not experience periparturient disease at the first calving (HR 0.67, 95% CI 0.50 to 0.91, P = 0.009). Increases in weight gain during the first breeding to first calving period by 0.1 kg/day increased the daily hazard of conception by a factor of 1.10 (95% CI 1.01 to 1.21, P = 0.038). We conclude that of all the growth periods assessed in this study, events that occurred during the first breeding to first calving period (474 to 804 days) had the greatest association with reproductive performance in the first lactation. There should be a focus on increasing growth rates during this period and reducing the risk of stillbirth and periparturient disease to improve reproductive performance in the subsequent mating period after calving.

Diel rhythm of volatile emissions from males and females of the olive fruit fly Bactrocera oleae using PTR-ToF and GC–MS

The olive fruit fly Bactrocera oleae, is the major key pest of olive groves worldwide. As an odor-driven species, its intraspecific communication has been thoroughly investigated, yielding a combination of spiroacetals, esters and hydrocarbons. However, its management with pheromone is still restricted to olean, the major pheromone component. Given the crucial role of circadian rhythm and pheromone blends in mediating flies reproductive behavior compared to single compounds, B. oleae headspace chemical profile was carefully examined, through the combination of Proton Transfer Reaction Time of Flight Mass Spectrometry (PTR-ToF) and Gas Chromatography coupled with Mass Spectrometry (GC–MS). This novel approach aimed at continuously investigating the temporal scale of volatilome profile of B. oleae individuals, as well as the determination of new candidate sex-borne compounds (particularly those emitted in traces or having low molecular weight), that may be relevant to the fly’s chemical communication and were unreported due to limitations of frequently used analytical techniques. Our results describe the dynamics and diversity of B. oleae chemical profile, highlighting the emission of 90 compounds, with clear diel rhythm of release, of known pheromone components of B. oleae (e.g., olean, alpha-pinene and muscalure) and new candidates. In contrast to ammonia, acetaldehyde and muscalure, which were highly emitted during the afternoon by males and mixed groups, olean was mostly released by mature females and mixed groups, with a peak of emission during early-morning and afternoon. This emission of olean around dawn is reported for the first time, suggesting early-morning mating activity in B. oleae. Furthermore, esters, such as methyl tetradecanoate, which had been earlier identified as a pheromone for B. oleae, did not exhibit any discernible release patterns. These findings are the first to demonstrate the emission of chemicals, which are only produced when males and females are close to one another, with an emission peak during the afternoon (mating period), and that may have aphrodisiac properties for B. oleae males. These results emphasize the relevance of compounds with distinct diel rhythm and address their potential function as intraspecific messengers, according to their source and timing of release.