Reproductive biology of Lepidocephalichthys guntea: a key conservation approach considering environmental factors in Payra River, Bangladesh.

The guntea loach, Lepidocephalichthys guntea, is categorically common freshwater fish in Southeast Asia. Current study is the first elucidation on the reproductive feature of L. guntea including population structure, sex ratio (SR), size at first maturity (Lm), breeding period, and condition factor, emphasizing on the effect of environmental factors on reproduction of this fish in the Payra River (Southern Bangladesh) during July 2021 to June 2022. Using various conventional gears, 1128 individuals (534 males and 594 females) have been collected. Total length (TL), standard length (SL), and body weight (BW) of each fish were measured. Ovaries were cautiously dissected, removed, and precisely weighed. TL ranges from 4.6 to 9.7 cm (BW = 0.7-9.27 g) for male and 4.6-10.3 cm (BW = 0.8-10.75 g) for female. Both male (47.34%) and female (52.66%) populations were the leading group in 7.00-7.99 cm TL. Overall SR was not notably altered from anticipated value of 1:1 (male:female = 1:1.11). Nonetheless, monthly variations of SR specified females were considerably outnumbered males in each month excluding March-May. Lm range was 6.4-7.0 cm, so larger than Lm is recommended to exploit. Monthly changes in GSI indicated that the main spawning season was from March to June. The spawning season was substantially correlated with rainfall, nonetheless with temperature. Additionally, relative weight indicated that habitat was imbalanced with higher predators. A fishing ban is recommended during peak spawning to protect L. guntea in the Payra River and its surroundings based on current research.

Effect of prostaglandin treatment on the estrus behaviour, follicular and luteal morphometry and serum hormone profile in sub-estrus buffaloes during non-breeding season.

Sub-estrus buffaloes do not exhibit estrus signs despite being cyclic contributing to extended service periods and inter-calving intervals causing significant economic loss. The present study described the effect of synthetic prostaglandin (PGF2α) on estrus behaviour, follicular and luteal morphometry, and serum estradiol (E2) and progesterone (P4) profile in sub-estrus buffaloes during the non-breeding season. The incidence of sub-estrus was 38.4% during the non-breeding season. The sub-estrus buffaloes (n = 33) were divided into two groups, viz., Control (n = 16) and PGF2α treatment (Inj. Cloprostenol 500 µg, i.m., n = 17). Estrus induction response was significantly greater in the treatment (100 vs. 18.75%, p < .001), and a relatively greater proportion of animals conceived in the treatment group (29.41 vs. 6.25%, p = .08). The time elapsed to induction of estrus and insemination following treatment was significantly lower in the treatment group than control. A significant increment in the follicle diameter (9.72 ± 0.45 vs. 13.00 ± 0.45 mm, P < .0001) and serum estradiol (E2) concentration (66.01 ± 11.92 vs. 104.9 ± 13.21 pg/mL, p = .003) observed at the post-treatment period in the PGF2α treatment group. At the same time, CL diameter was reduced significantly at a higher regression rate in the PGF2α treated buffaloes than those of control. Of the responded buffaloes, only 30% showed high-intensity estrus attributed to the expulsion of cervico-vaginal mucus (CVM), uterine tonicity, micturition, and mounting response by a teaser bull. From this study, it can be concluded that the administration of PGF2α could induce estrus in the sub-estrus buffaloes during the non-breeding season. Behavioural changes, along with sonographic observation of POF, regressing CL, and serum E2 and P4 concentration would be useful to determine the right time of insemination in sub-estrus buffaloes during non-breeding season.

Optimizing ReBreed21 II: Fertility and reproductive efficiency in different parities during a shortened breeding season in beef cattle.

This study evaluated the efficiency of a rapid reinsemination program allowing timed AI (TAI) every 21d (ReBreed21) in a commercial beef cow-calf operation. Nelore females from different parities (n = 2085) were synchronized for first TAI (D0 = TAI) using an estradiol/progesterone (E2/P4) protocol and assigned to one of three reinsemination programs: Resynch33 (n = 753), traditional resynch program with second TAI at D42 after first TAI; ReBreed21 (n = 687); or ReBreed21+EC (n = 670). The ReBreed females (n = 1357) received intravaginal P4 insert on D12, on D19 P4 was removed, and a dose of equine chorionic gonadotropin (eCG) was administered, then, ReBreed21 females received 0.6 mg of EC (ReBreed21+EC) or nothing (ReBreed21) and on D21, nonpregnancy (NP) was determined using Doppler ultrasound to detect corpus luteum (CL) blood flow (BF) (NP: <25 % BF pixels of total CL area) and NP cows received immediate TAI and GnRH to induce ovulation. Pregnancy diagnosis was performed at D33 after TAI following all TAIs. Cows considered pregnant at D21, based on CL BF, but NP on D33 were designated False-Positives (FP) and false negatives (FN) were number of nonpregnant cows/heifers on d21 based on the CL BF found to subsequently be pregnant on D33 divided by the total number pregnant. Pregnancy/AI (P/AI) did not differ for the first TAI (55.1 %) among the treatments. Heifers had similar P/AI at the second AI in all groups and similar to the first AI. Primiparous had greater P/AI in ReBreed21+EC and Resynch33 at s TAI compared to ReBreed21, 51.7 %, 55.8 %, 34.2 %, respectively. Multiparous had greater P/AI at second TAI in Resynch33 (60.9 %) than ReBreed21 programs (34.7 %). The percentage FP and FN among ReBreed21 programs did not differ, 13.8 and 0.2 %, respectively. Overall accumulative pregnancies on D21 of the breeding season were greater for ReBreed21 and ReBreed21+EC than Resynch33 (69.7 %, 71.6 %, and 55.5 %, respectively). However, on D42 of the breeding season, only heifers had greater pregnancies in ReBreed21 programs than Resynch33 (73.3 %, 74.3.6 %, and 63.2 %, respectively). Average days to pregnancy were less (P = 0.01) for ReBreed21 and ReBreed21+EC than Resynch33. Thus, the ReBreed21 strategy can improve the efficiency of TAI programs in beef cattle. Of interest, ReBreed21 was particularly effective in nulliparous, somewhat effective in primiparous when EC was added to the program, but relatively ineffective in multiparous beef cattle.

Uterine tone influences fertility of Merino ewes following laparoscopic artificial insemination.

Artificial insemination (AI) plays a critical role in facilitating rapid genetic and production gains within the sheep industry. However, variable rates of AI success remain a concern for the industry and a barrier to adoption. Furthermore, the degree to which female factors influence the success of intrauterine laparoscopic AI rather than natural mating remains unknown. As such, this study investigates the effect of several factors collected during the time of AI, on the success of intrauterine laparoscopic AI. Data was generously donated by artificial breeding companies and stud breeders during routine commercial AI operations. AI data was collected over 3 breeding seasons during commercial AI programs (N = 24 programs) using Merino ewes (N = 24,700). Sire ID (N = 253), time of AI following progesterone removal (approx. 43-59 h post removal), uterine tone and intra-abdominal fat (both scored 1-5) as well as age of the ewe were all recorded at the time of AI. Transcutaneous ultrasound subsequently determined pregnancy rate approximately 55 days post-AI. A multivariate regression analysis was performed and revealed pregnancy success to increase when semen was inseminated into a ewe with a uterine tone score of 4 or 5 (P < 0.001). The remaining factors fell short of significance within the multivariate model. An interclass coefficient variation matrix was also used to determine the proportion of variation contributed to AI success by random factors allocated in the model; site, sire, AI date and breeding season (45.99 %, 29.94 %, 15.15 % and 8.92 %, respectively). These results highlight the influence of uterine tone on ewe fertility following laparoscopic AI, but also that program location and the sire used can further modify this influence on pregnancy rate. These factors must now be considered in combination with semen factors per individual sire used during AI to ascertain the contribution of several factors to the success of laparoscopic AI in Australia.

Seasonal investigation of the macroscopic and microscopic structure of the sinus interdigitalis in Hamdani crossbred sheep (Ovis aries).

BACKGROUND: The odours of different body parts and structures, such as external genitalia, female urine, ventral tail radix, infraorbital sinus and interdigital sinus, have a strong attractiveness for rams. The sinus interdigitalis is considered an important trail gland for sexual behaviour, as its odour is included in the list of strongly attractive structures for male animals during the breeding season, being important in pheromone production. OBJECTIVES: In the present study, the effects of sex and breeding season on the morphological and histological structure of the interdigital gland were investigated in Hamdani crossbred sheep (Ovis aries). METHODS: Sinus interdigitalis glands located on the forelimbs and hind limbs were collected from 10 male and 10 female sheep during both breeding and non-breeding seasons. The gland's position in the forelimbs and hind limbs was determined radiographically. The glands were examined macroscopically, histologically and immunohistochemically in both seasons. RESULTS: In all animals, the topographic location of the gland between the digits was determined to be distal to the phalanx proximalis and at the level of the phalanx media. The mean weight of the gland in male and female animals was 1.07 ± 0.03 and 1.4 ± 0.11 g, respectively. In general, the results of morphometric measurements were higher during the breeding season, and the increase was more pronounced in female animals. In histological examinations, it was determined that both neck and body parts of the tissues consisted of a structure consisting of a connective tissue capsule at the outermost, dermis, epidermis and lumen underneath. Immunohistochemically staining revealed that oestrogen receptors showed positive immunoreactions only in the intracytoplasmic localization of apocrine sweat glands. In terms of morphological, histological and oestrogen receptors, it was thought that the gland may play a role in sexual communication.

The reproductive biology of Ellochelon vaigiensis from the Vietnamese Mekong Delta.

The Squaretail mullet, Ellochelon vaigiensis, is a commercial fish species distributed throughout the Indo-Pacific region. This species tolerates wide variations in salinity, having been reported from both freshwater and marine habitats. Although economically significant, there is little information on its reproduction, especially in the Vietnamese Mekong Delta (VMD), where it is heavily extracted. Our study elucidates the breeding pattern, seasonality, first length at maturity, as well as potential and relative fecundity of this species. Fish specimens were collected by trawl nets from November 2020 to October 2021 at four estuarine sites within the VMD. We found this species to be a synchronous spawner, with peaks in reproductive activity from June to September. In the populations we surveyed, there was significant dominance of males (1.26:1.00) based on 942 fish samples (526 males and 416 females). The length at 50% maturity for females was significantly higher than for males at all sites and ranged from 10.6 to 19.3 cm. The diameter of the eggs examined for this species exhibited slight variation, from 0.43 to 0.54 mm. The potential fecundity ranged from 246,254 ± 35,878 to 411,970 ± 54,370 eggs, corresponding to female length and weight of 26.7-32.6 cm and 102.97-234.19 g, respectively. Relative fecundity values were highest at Thanh Phu, Ben Tre (6388 ± 605 eggs), and Dong Hai, Bac Lieu (6461 ± 637 eggs), followed by Tran De, Soc Trang (4729 ± 408), and were found to be lowest at Duyen Hai, Tra Vinh (3117 ± 223 eggs). Information on reproductive behavior in this species has far-reaching impacts on sustainable extractions, stock conservation, and aquaculture.

Reproductive Seasonality, Estrous Cycle, Pregnancy, and the Recurrence of Postpartum Estrus Based on Long-Term Profiles of Fecal Sex Steroid Hormone Metabolites regarding Zoo-Housed Female Golden Takins (Budorcas taxicolor bedfordi).

This study investigates the non-invasive monitoring of the endocrine ovarian activities of captive female golden takins (Budorcas taxicolor bedfordi) based on long-term fecal sex steroid hormone metabolite dynamics. Fecal progesterone (P4) metabolite dynamics were monitored in nine females for 0.5-15 years between 2004 and 2022. Fecal estradiol-17ß (E2) and estrone (E1) metabolites were measured during certain estrous cycles, and fecal E1 metabolite concentrations were measured during all gestation periods. The breeding season of the captive animals was mainly between May and December, and they were polyestrous animals whose breeding season begins during the long-day period. The onset of the breeding season occurred slightly earlier as age increased. The mean age (±SD) at puberty based on fecal P4 metabolite dynamics was 4.1 ± 2.9 years. The first conception ages ranged from 2.3-10.2 years. The mean estrous cycle period (±SEM) was 25.4 ± 1.1 days, and mounting and mating occurred in periods of low fecal P4 metabolite levels during the breeding season. The mean gestation period (±SD) from the estimated mating date to the calving date was 253.9 ± 5.7 days, and the fecal P4 metabolite distribution during pregnancy was bimodal. Fecal estrone metabolite levels gradually increased 21 weeks before delivery, peaked during the week of delivery, and then markedly decreased in the first week after delivery. Estrus resumed in the first April-August period after delivery (mean ± SD; 103.5 ± 40.9 days) or in May of the year after delivery (421.0 ± 16.5 days). This study revealed that the estrous cycle and pregnancy of female golden takins can be determined by fecal progesterone metabolite dynamics and that fecal estrone metabolite dynamics increases toward parturition and are useful for predicting the date of delivery. This endocrinological information is important for planned breeding efforts for the golden takins.

Semelparous marsupials reduce sleep for sex.

Sleep is a prominent, seemingly universal animal behavior. Although sleep maintains optimal waking performance, the biological drive to sleep may be incompatible with the life history of some species. In a multi-year study on semelparous marsupials in Australia, we provide the first direct evidence of ecological sleep restriction in a terrestrial mammal. Dusky (Antechinus swainsonii) and agile (A. agilis) antechinus have an unusual reproductive strategy characterized by the synchronous death of all males at the end of their only breeding season. Using accelerometry, electrophysiology, and metabolomics, we show that males, but not females, increase their activity during the breeding season by reducing sleep. In a trade-off between the neurophysiological requirements for sleep and evolutionary necessity for reproduction, strong sexual selection might drive males to sacrifice sleep to increase access to fertile females and ultimately maximize their fitness.

The Effect of Supplemental Lighting during the Late Gestation Period on Post-Partum Mechanical Properties of Mare and Foal Guard Hair.

This study investigates Thoroughbred mares exposed or not to supplemental blue light at the end of the gestation. Sixty mares and their 60 foals were selected for the investigation. Guard hair samples were collected from the shoulder just after (within 12 h) the parturition or birth. The foals of the light-treated mares developed significantly (p < 0.05) shorter hair than those of the control mares. A general effect of light treatment on basal hair diameter thinning could be demonstrated (p < 0.005). The maximum force of hair samples of light-treated mares and foals (0.098 and 0.085 N, respectively) was significantly lower than that of the control (0.272 and 0.178 N, respectively). The tensile strength (82.2 N/mm2) of the foal hair samples of the light-treated mares was significantly lower than that of the control foals (121.6 N/mm2). Although no significant difference was found in the elongation (ΔL), the hair of the control animals (mares and foals together) was more elastic than that of the treated animals (335 vs. 262 µm). In conclusion, the supplemental blue light treatment of the pregnant mares has a decreasing effect on both mares and their foals on the mechanical properties of the hair, making it shorter, thinner, and weaker.

Uncommon life history and winter spawning of common carp (Cyprinus carpio) in a natural thermal spring, under temperate climate.

Common carp female generally matures at age 4-5 years old and spawns between April and July under the temperate climate. Contrary to a range of 0-28 °C of temperate freshwaters, the water temperature of Lake Hévíz (Hungary, Central Europe), the largest natural bathable thermal lake in the world, varies between 26 and 35 °C seasonally. The specific environmental conditions (continuously warm water and its individual chemical composition, special nutrient base, lack of natural lakeside spawning substrate compared to usual spawning grounds, continuous high human disturbance, etc.) suggest that the carp population here may also differ in reproductive characteristics from their counterparts in surrounding waters. Our findings suggest that the self-sustaining dwarf common carp population of Lake Hévíz matures 2 to 4 years earlier (at the age of one) and spawns 1 to 3 months before (between February and April, at 27-30 °C water temperature) than carp typically do in the temperate zone (16-20 °C). Successful winter spawning was verified by rearing larvae from the collected eggs and in situ induced propagation.

Seasonal variations of the epididymis in donkeys (Equus asinus) with special reference to blood epididymal barrier.

The epididymis, a key component of the male reproductive system, controls spermatozoa's maturation, fertility, and storage. The objective of this study is to evaluate the histological, ultrastructural, and immunohistochemical variations in the epididymis of donkeys that occur throughout the year. During the breeding season (spring) and nonbreeding seasons (summer, autumn, and winter), 20 epididymis were collected from adult, clinically healthy donkeys. Compared to non-breeding seasons, the epididymal duct displayed a more active lining epithelium and more sperm in the lumen during the breeding season. The epithelial height is the lowest and the lumen is the widest during the breeding season. Furthermore, the epididymal epithelium in the tail region exhibits undulations with polyps-like projections. The epididymal epithelium is composed mainly of the principal, basal, and dark cells. Tight junction between adjacent principal cells is more obvious in the breeding season as compared to the non-breeding seasons. However, intraepithelial lymphocytes, phagocytic, and other immune cells are more frequent in non-breeding seasons. ß-catenin, which is a component of the adherent junctions between adjacent PCs, exhibits more immunoreactivity during the spring. On the other hand, iNOS, an indicator of oxidative stress, reacts positively during the summer. Additionally, during non-breeding seasons, autophagy was detected within the epididymal epithelium which may be linked to stress adaptation. In conclusion, our findings suggest that the histological and ultrastructural characteristics of the epididymal epithelium are more active during spring compared to other seasons of the year. RESEARCH HIGHLIGHTS: The study aimed to evaluate the histological, ultrastructural, and immunohistochemical variations in the blood epididymal barrier (BEB) and epididymal epithelium of donkeys that occur throughout the year. In comparison to non-breeding seasons, the epididymal duct displayed a more active lining epithelium and more sperm in the lumen during the breeding season. The epithelial height is the lowest and the lumen is the widest during the breeding season. The epididymal epithelium in the tail region exhibits undulations with polyps-like projections that increase the surface area. ß-catenin, which is a component of the adherent junctions between adjacent PCs, exhibits more immunoreactivity during the spring. On the other hand, iNOS, an indicator of oxidative stress, reacts positively during the summer.

Progesterone Device Use Improves Ovum Pick-Up Efficiency in Acyclic Donors.

The aim of this study was to evaluate follicular dynamics and ovum pick-up (OPU) efficacy in untreated mares or mares treated with an intravaginal progesterone (P4) device during seasonal anestrus (acyclic) and during the breeding season (cyclic). Six mares (mean age = 5 years), were recruited into an ovum pick-up scheme that was performed every 14 days with and without the P4 device, during the acyclic and cyclic phases. Aspirations amounted to seven procedures with or without the P4 device during each phase. Five ultrasound assessments were performed at each interval between the OPUs. Data on follicular number and diameter as well as the numbers of recovered and the percentage of recovered oocytes were also collected. The number of follicles from mares in the acyclic phase was higher (P < .005) regardless of the treatment. However, the follicular diameter was smaller for the P4 group (P < .005) from the 2nd to the 5th evaluation post-OPU procedure. The percentage of oocytes recovered during the acyclic phase was higher for mares treated with the P4 device (P < .005). The P4 device resulted in follicles with smaller diameters and facilitated OPU efficacy.

Seasonal variations of testis anatomy and of G-coupled oestrogen receptor 1 expression in Gerbillus gerbillus.

The gerbil, Gerbillus gerbillus, a nocturnal desert rodent of northern Africa, exhibits a seasonal reproductive cycle with marked anatomical and behavioural shifts between breeding season and resting season. The aim of this study is to investigate key elements involved in these seasonal changes, specifically in males: the histology of the testis as well as the expression of the G-protein-coupled oestrogen receptor 1 (GPER1) in the testis. During the breeding season, the seminiferous tubules were full of spermatozoa, and their epithelium contained germinal cells embedded in Sertoli cells. Amidst tubules, well-developed Leydig cells were observed around blood vessels, with peritubular myoid cells providing structural and dynamic support to the tubules. GPER1 was largely expressed throughout the testis. Notably, Leydig cells, spermatogonia and spermatocytes showed strong immunohistochemical signals. Sertoli cells, spermatozoa and peritubular myoid cells were moderately stained. During the resting season, spermatogenesis was blocked at the spermatocyte stage, spermatids and spermatozoa were absent and the interstitial space was reduced. The weight of the testis decreased significantly. At this stage, GPER1 was found in Leydig cells, spermatocytes and peritubular myoid cells. Sertoli cells and spermatogonia were not marked. Overall, the testis of the gerbil, Gerbillus gerbillus, has undergone noticeable histological, cellular and weight changes between seasons. In addition, the seasonal expression pattern of GPER1, with pronounced differences between resting season and breeding season, indicates that this receptor is involved in the regulation of the reproductive cycle.

Estimating peak breeding season, size at first maturity and variation in fecundity and egg-size at different sizes of Hilsa (Tenualosa ilisha).

Hilsa shad, Tenualosa ilisha, has recently gained momentum due to its taste, nutrition and demand. Imposing ban at peak breeding and setting up a minimum capture size are two of the most effective tools for conservation and management of any fish species. Although, Bangladesh government has been imposing ban on a particular time and set the minimum legal size, there is still contradictory information on these two issues. That is why, a study was carried out to determine peak season of breeding and first maturity of Hilsa collected across the natural habitats in Bangladesh. Variation in fecundity and egg-size at different sizes were also investigated. Peak breeding season was identified observing gonadosomatic index of female Hilsa all the year round. First maturity was estimated with Probit analysis. Based on the gonadosomatic index of gravid females, peak breeding season was identified as late October to early November in this study. However, another minor peak was found in February-March. The highest GSI value (12.1) was observed in October-November, which indicates the peak time of spawning. The size at maturity (M50) of female Hilsa was estimated as 31 cm total length. A significant variation was observed in egg sizes between the left and right lobes of the fish (t (24) = 2.42, p = 0.02), and between the parts of the same lobe (p = 0.03). However, fish length and weight had no effect on egg size(for egg-size vs. fish length, r = -0.009, p = 0.966; and for egg size vs. body weight, r = 0.132 and p = 0.530). The average egg count from left lobe and right lobe were recorded as 0.375 ± 0.16 million, 0.371 ± 0.17 million. Total fecundity was counted as 0.745 ± 0.33 million. A significant positive correlation was noticed between length, weight, and total fecundity (r = 0.7 for total fecundity vs. body weight; r = 0.6 for of total fecundity vs. length). No significant variation was observed in fecundity between the left and right lobe (p = 0.6) and among three parts of a lobe (p = 0.3). The size of eggs varied between two lobes and among different parts of a lobe. The eggs from middle part were bigger in size than the other parts. The findings of our study will help conserve and manage the natural population of Hilsa (T. ilisha) in Bangladesh and contribute to the wider scientific community.

Hunting Site Behaviour of Sympatric Common Buzzard Buteo buteo and Rough-Legged Buzzard Buteo lagopus on Their Wintering Grounds.

Birds wintering in the northern Palearctic compensate for substantial energy losses and prepare for a food deficit in winter by adjusting their foraging behavior. Apart from weather conditions, interspecific competition also drives hunting strategies. To describe this phenomenon, we observed the behavior of two sympatrically wintering raptor species: the Common Buzzard and the Rough-legged Buzzard. The study was carried out in east-central Poland during four seasons on a study plot where the densities of both species were high. Interspecific differences were detected in the use of available hunting sites. Rough-legged Buzzards conspicuously avoided using fence posts for scanning the surroundings and spent the most time standing on the ground. Common Buzzards more often used trees for this purpose when the snow cover was thick. Thicker snow cover resulted in fewer attempted attacks on prey in both species and caused Common Buzzards to change their hunting sites less frequently. The study also showed that the more often a bird changed its hunting site, the greater the number of attempted attacks. The outcome is that the ultimate effectiveness of hunting is mediated by the overview of the foraging area from different heights and perspectives, not by the type of hunting site. Snow cover was the most important factor in modifying foraging behavior and possibly intensifying interspecific competition.

Reproductive phenologies of phyllostomid bat populations and ensembles from lowland Amazonia.

Natural selection should favor individuals that synchronize energy-demanding aspects of reproductive activity with periods of high resource abundance and predictability, leading to seasonal patterns of reproduction at the population level. Nonetheless, few studies-especially those on bats in the Neotropics-have used rigorous quantitative criteria to distinguish among phenological patterns for different populations from the same habitat or for the same species in different habitats. To explore such issues, we quantified annual patterns of reproduction in male and in female bats from lowland Amazonia (environs of Iquitos, Peru), and did so at the level of populations and ensembles. Five species exhibited unimodal patterns including Artibeus obscurus, A. planirostris, Carollia benkeithi, Phyllostomus hastatus, and Rhinophylla pumilio. Two species (A. lituratus and Glossophaga soricina) evinced bimodal patterns with reproductive peaks separated by patterns of inactivity, whereas four species (C. brevicauda, C. perspicillata, Sturnira lilium, and S. tildae) evinced a bimodal pattern in which peaks in activity occur in tandem, with the first peak generally markedly higher than the second peak. Frugivore, gleaning animalivore, and nectarivore ensembles exhibited bimodal, unimodal, and bimodal reproductive phenologies, respectively. Nonetheless, interannual variation in phenology (i.e., the monthly timing of peaks within a season rather than the number of peaks per year) characterized four (A. obscurus, C. brevicauda, C. perspicillata, and S. lilium) of the eight species and each of the three ensembles (frugivores, gleaning animalivores, and nectarivores) with adequate sampling. Regardless of interspecific variation in strategies, the phenology of reproduction enhances the likelihood that parturition and recruitment of young into the population occurs during the wet season, the period of likely highest resource abundance. Based on a comparison of our results with those from other well-studied bat populations, four species did not exhibit geographic variation in reproductive phenologies (A. obscurus, G. soricina, C. brevicauda, and R. pumilio), whereas three species evinced such geographic variation (A. lituratus, A. planirostris, and C. perspicillata). Climate change will likely alter the seasons and extents of propitious times for reproductive activities, as well as the reliability of proximate cues for initiating reproduction, compromising current reproductive strategies and leading to altered phenological patterns of reproduction or reproductive success, possibly resulting in local extinction of some species.

La selección natural debería favorecer a individuos que sincronicen aspectos de alta demanda de energía en su actividad reproductiva con períodos de alta abundancia y previsibilidad de recursos, lo que conduciría a patrones estacionales de reproducción a nivel poblacional. No obstante, pocos estudios, especialmente estudios sobre murciélagos en el Neotrópico, han utilizado criterios cuantitativos rigurosos para distinguir entre patrones fenológicos ya sea para diferentes poblaciones dentro del mismo hábitat o para la misma especie en diferentes hábitats. Para explorar este tema, cuantificamos los patrones anuales de reproducción de murciélagos machos (porcentaje de la población con testículos escrotales) y hembras (porcentaje de la población embarazada o lactante) en regiones bajas de la Amazonía (alrededores de Iquitos, Perú) a nivel de poblaciones y de ensamblajes. Cinco especies exhibieron patrones unimodales, incluidos Artibeus obscurus, Artibeus planirostris, Carollia benkeithi, Phyllostomus hastatus, y Rhinophylla pumilio. Dos especies (Artibeus lituratus y Glossophaga soricina) mostraron patrones bimodales, con picos reproductivos separados por patrones de inactividad, mientras que cuatro especies (Carollia brevicauda, Carollia perspicillata, Sturnira lilium, y Sturnira tildae) mostraron un patrón bimodal en el que los picos de actividad ocurren en tándem, con un primer pico considerablemente más alto que el segundo. Los grupos de frugívoros, animalívoros y nectarívoros exhibieron fenologías reproductivas bimodales, unimodales y bimodales respectivamente. No obstante, la variación interanual en la fenología (es decir, el mes dentro de una temporada en que ocurren los picos en lugar del número de picos por año) caracterizó a cuatro (A. obscurus, C. brevicauda, C. perspicillata y S. lilium) de las ocho especies y cada uno de los tres ensamblajes (frugívoros, animalívoros y nectarívoros) con un tamaño de muestra adecuado. Independientemente de la variación en las estrategias, la fenología en la reproducción aumenta la probabilidad de que el parto y el reclutamiento de crías en la población ocurran en la estación húmeda, el período de mayor abundancia de recursos. Cuando comparamos nuestros resultados con los de otras poblaciones de murciélagos mejor estudiadas, cuatro especies no mostraron variación geográfica en sus estrategias reproductivas (A. obscurus, G. soricina, C. brevicauda y R. pumilio), mientras que tres especies si mostraron esta variación geográfica (A. lituratus, A. planirostris y C. perspicillata). Es probable que el cambio climático altere las estaciones y la duración de los periodos propicios para el desarrollo de actividades reproductivas de alta demanda de energía, así como la regularidad de las señales activantes para iniciar la actividad reproductiva, comprometiendo las estrategias reproductivas actuales y conllevando a patrones fenológicos de reproducción alterados, lo que para algunas especies podría resultar en extinciones locales.

Highly pathogenic avian influenza affects vultures' movements and breeding output.

An exceptional highly pathogenic avian influenza (HPAI) outbreak due to H5N1 virus genotypes belonging to clade 2.3.4.4.b has been affecting birds worldwide since autumn 2021.1,2,3 Mortality caused by viral infection has been well documented in poultry and more recently in wild birds, especially in seabird-breeding colonies.4,5,6 However, there is a critical lack of knowledge about how terrestrial birds deal with HPAI virus infections in terms of behavior and space use, especially during the breeding season.7,8,9 Understanding how birds move when they are infected could help evaluate the risk of spreading the virus at a distance among other populations of wild or domestic birds, this latter risk being especially important for commensal bird species. Through long-term GPS tracking, we described the changes in daily movement patterns of 31 adult griffon vultures Gyps fulvus in two French sites in 2022 compared with 3 previous years. In spring 2022, 21 vultures at both sites showed periods of immobility at the nest, during 5.6 days on average. Positive serological status of 2 individuals confirmed that they had been infected by HPAI viruses. Death was recorded for 3 of the 31 tracked individuals, whereas all others recovered and returned quickly to their foraging routine, although at least 9 birds failed breeding. Such immobility patterns and death rates were never observed in previous years and were not related to weather conditions. The high immobility behavior of infected birds could reduce the risks of transmission. The observed vulnerability to HPAI viruses questions the resistance of endangered vulture species worldwide if infected.

Research on timed AI in beef cattle: Past, present and future, a 27-year perspective.

This review aimed to (1) summarize the results from fixed-timed artificial insemination (TAI) fertility studies performed during the last 27 years; (2) compile and evaluate, as examples from the literature base, the direct comparisons made of specific manipulations to synchronization protocols; (3) evaluate the impact of the TAI programs on the reproductive performance during the breeding season, and (4) provide perspective on the future of TAI programs in beef cattle. A search of the literature published from 1995 to 2021 was conducted to identify experiments in which synchronization of ovulation and TAI in beef cattle was performed. The primary outcome of interest was fertility expressed as pregnancies per TAI. The literature included two search engines, the SIS Web of Science and the US National Library of Medicine Institutes of Health through PubMed. After the initial search and screening, a total of 228 manuscripts were selected containing a total of 272,668 TAI. A dramatic increase in the number of publications and TAIs occurred throughout the years. Most of them were from Brazil and United States, followed by Canada, Argentina, Uruguay, and Australia. Two main types of TAI programs were identified: GnRH-based and E2/P4-based protocols. In terms of GnRH-based programs, two variations were evaluated in the present manuscript. First, we evaluated the effect of the progesterone implant during the protocol. The progesterone implant increased pregnancy/TAI (P/TAI) from 44.3 to 54.3%. Second, the use of a second prostaglandin F2α treatment in 5-d CO-synch program increased the P/TAI from 53.2 to 60.9%. In E2/P4-based programs, use of GnRH at TAI increased P/TAI from 54.7 to 59.2% in cows. However, no increase was detected in heifers. Other research showed that use of TAI can increase the overall proportion of the cows pregnant at end of the breeding season and produce earlier calvings compared with bulls. In conclusion, there have been a large number of excellent research studies that have been performed during the last 27 years on TAI in beef cattle. This technology is being utilized successfully in the beef cattle industry. This success is largely because of the valid research that underlies the application of the technology and the economic value of the technology.

Calving date as a potential predictor for the probability of approval in the first breeding soundness evaluation of Nellore bulls.

Beef production systems primarily use natural service (NS) for breeding. However, a significant number of bulls used for NS are subfertile, limiting the profitability of the cow-calf operations. Therefore, producers should select bulls based on breeding soundness evolutions (BSE) to ensure higher pregnancy rates. Several factors can affect the bull ability to pass a BSE. We hypothesize that calving date would be a factor that affects the bull probability of approval at the first BSE. For this purpose, a multivariate logistic regression in a dataset of 14,737 BSEs from young Nellore bulls was used. Correlations between calving date, biometrics, and semen traits were evaluated using Pearson's correlation coefficient. Our results demonstrated that the calving date affected the probability of approval at the first BSE (p < .05). Indeed, the variable that added more information to our model was the calving date, far more than the age group of the bulls according to Akaike's information criterion. Hence, bulls born on day 0 of the calving season have 1.26 more chances to be approved at the first BSE than bulls born 21 days later. This result highlights the importance of getting the dams of future bulls pregnant as soon as possible in the breeding season. In addition, the calving season should be no longer than 47 days to achieve 80% BSE approval in 20-22 months old Nellore bulls. The strongest correlation was with SC, which decreased as the calving date increased. Therefore, the calving date may be used as a predictor of the outcome of the first BSE in young bulls. In that way, the calving date can help seedstock producers to maximize efficiency in making crucial management decisions during the breeding and calving season including nutrition, reproductive, and culling.

Effect of pentoxifylline on the testicular hemodynamic, volume, testosterone, nitric oxide levels and semen quality in Ossimi rams during non breeding-season.

During the non-breeding season, Ossimi rams have testicular regression, including reductions in blood flow, size and spermatogenesis. The objective was to determine the effect of pentoxifylline (PTX) on Ossimi rams during the non-breeding season. Fifteen sexually mature Ossimi rams were allotted to three groups: (1) G0 (n = 5) control group (basic diet, no PTX); (2) G1 (n = 5) 10 mg/kg BW PTX; and (3) G2 (n = 5) 20 mg/kg BW PTX. The PTX was given orally once daily for 7 weeks (wk1 to wk7), whereas ultrasonographic assessment of testes, and collection of semen and blood started 1 week before PTX and were done weekly for 8 weeks (wk0 to wk7). In G2, there was a decrease(P < 0.05) in both Doppler indices (resistive index, pulsatility index) in G2 from wk2 to wk4 and an increase(P < 0.05) in ultrasonographic testicular coloration from wk2 to wk7. Moreover, G2 had the highest (P < 0.05) testicular volume (wk5 to wk7), individual motility, sperm viability and acrosome integrity (wk4 to wk7) and sperm cell concentration (wk6 and wk7). Blood concentrations of testosterone and nitric oxide were increased (P < 0.05) concurrent with decreased Doppler indices. In conclusion, PTX enhanced testicular blood flow and volume, semen quality, and concentrations of testosterone and nitric oxide potential in Ossimi rams during the non-breeding season, with potential to ameliorate deleterious effects of heat stress and perhaps enhance ram fertility.