Search Results (241)

Honeybees (Apis mellifera) are pollinators for most crops in nature and a core species for the production of bee products. Body size and body weight are crucial breeding traits, as colonies possessing individuals with large body weight tend to be healthier and exhibit high productivity. In this study, small interfering RNA (siRNA) targeting 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) was incorporated into the feed for feeding worker bee larvae, thereby achieving the silencing of this gene’s expression. The research further analyzed the impact of the RNA expression level of the 15-PGDH gene on the juvenile hormone (JH) titer and its subsequent effects on the body weight and size of worker bees. The results show that inhibiting the expression of 15-PGDH in larvae could significantly increase JH titer, which in turn led to an increase in the body weight of worker bees (1.13-fold higher than that of the control group reared under normal conditions (CK group); p < 0.01; SE: 7.85) and a significant extension in femur (1.08-fold longer than that of the CK group; p < 0.01; SE: 0.18). This study confirms that 15-PGDH can serve as a molecular marker related to body weight and size in honey bees, providing an important basis for molecular marker-assisted selection in honey bee breeding. Full article

Fish coloration plays an important role in reproduction and camouflage, yet capturing color variation under field conditions remains challenging. We present a standardized, semi-automated protocol for measuring body coloration in the popular model fish threespine stickleback (Gasterosteus aculeatus). Individuals are photographed in a controlled light box within minutes of capture, and color is sampled from eight anatomically defined standard sites in human-perception-based CIELAB space. Analyses combine univariate color metrics, multivariate statistics, and the ΔE* perceptual difference index to detect subtle shifts in hue and brightness. Validation on pre-spawning fish shows the method reliably distinguishes males and females well before full breeding colors develop. Although it currently omits ultraviolet signals and fine-scale patterning, the approach scales efficiently to large sample sizes and varying lighting conditions, making it well suited for population-level surveys of camouflage dynamics, sexual dimorphism, and environmental influences on coloration in sticklebacks. Full article

Brachycephalic head shape in dogs has been associated with behavioural traits that may enhance their appeal as companion animals, contributing to their popularity. However, it remains unclear whether these behavioural differences are directly linked to head shape or are mediated by factors such as body size, demographics, and dog-keeping practices. Drawing on two large-scale owner surveys (N = 5613) and cephalic index estimates for 90 breeds, we investigated the relationship between head shape and eight behavioural variables (four personality traits and four behavioural problems), while controlling for 20 demographic and dog-keeping characteristics, as well as body size. Our results show that behavioural differences among head shapes are only partly attributable to head shape itself; some are explained by confounding variables. Specifically, brachycephalic dogs appeared predisposed to positive behaviours (e.g., calmness, fewer behavioural problems), but these traits were often obscured by their small body size and low training experience. These findings highlight the complex interplay between morphology, behaviour, and environment, and emphasize the role of training and management in supporting the behavioural well-being of popular brachycephalic breeds. This has important implications for owners, breeders, and welfare professionals aiming to align aesthetic preferences with behavioural and welfare outcomes. Full article

This study analyzes 209 dog skeletons from two sites in Wolin (9th–mid-13th century AD) using 100 standard metric variables covering cranial, mandibular, and postcranial elements. Estimated withers height, body mass, age at death, and sex were derived using established methods. The results indicate the presence of at least two to three morphotypes: small spitz-like dogs (40–50 cm, 4–6 kg), medium brachycephalic forms (50–60 cm, 10–15 kg), and larger mesocephalic individuals (up to 65 cm, 20–40 kg). Dogs lived 3–10 years, with both sexes represented. Signs of cranial trauma and dental wear suggest utilitarian roles such as guarding. The size range and morphological diversity point to intentional breeding and trade-based importation. Small dogs likely served as companions or city guards, while medium and large types were used for herding, hunting, or transport. These findings highlight Wolin’s role as a dynamic cultural and trade center, where human–dog relationships were shaped by anthropogenic selection and regional exchange. Full article

As dogs are often required to be leashed in public, guardians need to choose between various restraint devices. While using collars typically considered aversive (such as choke, prong, or electric collars) is generally discouraged due to welfare concerns, guidance is less clear when it comes to selecting among other devices such as collars, harnesses, and head collars. This review examined 21 full-text articles and two abstracts on the effects of commonly used restraint devices, aiming to offer practical guidance for guardians and identifying areas for future research. The impact of these devices was examined in terms of walking kinematics, pressure distribution on the body, and behavioural signs of stress. The findings suggest there is no one-size-fits-all device, and selection should consider the individual needs of guardian and dog. For dogs that pull, non-tightening front-clip harnesses appear to offer the best balance between discomfort and reduction in pulling. Tightening harnesses, martingale collars, and head collars can pose greater discomfort and should be used with caution. For brachycephalic breeds or when pulling is not a concern, back-clip harnesses are suitable, especially chest-strap or Y-shaped ones. Flat collars are also appropriate for dogs that do not pull as they produce the least body restriction. Full article

The cryopreservation of rabbit semen is a valuable strategy for genetic resource preservation and efficient artificial insemination, but outcomes remain inconsistent, partly due to variations in sperm concentration per dose. This study aimed to evaluate the in vivo effects of different sperm concentrations (15, 25, 35, 55, and 75 million per straw) on fertility, prolificacy, and offspring growth in nulliparous and multiparous does. A total of 384 rabbit females were inseminated using frozen–thawed semen, and their reproductive performance was compared with fresh semen. Fertility and kindling rates varied with sperm concentration and parity: nulliparous does showed the highest fertility at 15 million sperm/straw (84.4%), while multiparous does reached peak values at 25–55 million/straw (78.1–81.3%). Litter size and live-born kits were consistently higher in multiparous than in nulliparous does. Offspring body weight at 19 and 60 days was influenced by both sperm concentration and maternal parity, with better growth generally observed in multiparous groups. Weaning success remained high across all groups. Our results indicate that sperm concentrations ranging from 15 to 35 × 10⁶/straw are the most suitable for cryopreservation, as they maintain high fertility, prolificacy, and offspring growth, comparable to fresh semen. These results confirm that optimizing sperm concentration during cryopreservation improves reproductive efficiency and that tailoring insemination strategies to the physiological status of the female enhances outcomes. The results provide useful recommendations for improving cryopreservation techniques in rabbit breeding programs. Full article

Sexual dimorphism is prevalent among animals, influencing both functional morphological traits and behavioral performances. In this study, we investigated the sexual differences in the morphological parameters of Kaloula borealis (Anura, Microhylidae) during the breeding season using 48 specimens. Our results reveal that among the 16 external morphological traits, females had significantly larger snout-vent length and eye diameter than males. The former presumably contributes to enhancing fertility, while the latter is associated with larger body size. Males exhibited significantly greater head width and thigh width than females, which may be related to accessing a wider range of food sources and enhancing their locomotor ability, respectively. Among the 32 appendicular muscles, 10 displayed significant sexual dimorphism in dry mass, suggesting divergent reproductive strategies between the sexes. Among the eight internal organs analyzed, males possessed significantly heavier hearts and lungs than females, which is likely an adaptation to higher metabolic demands and calling behavior. Collectively, our findings demonstrate that sex-specific differences in external morphology, muscle mass, and internal organ mass reflect distinct ecological and reproductive adaptations between males and females and contribute to the phenotypic diversities in Anura. Full article

This article highlights the importance of evaluating the morphological characteristics of female dogs during breeding soundness examinations (BSEs) to assess their reproductive potential and ensure the health of future offspring. Key traits considered in this evaluation include body type, body condition score, skull size and shape, mammary gland conformation, and coat quality. Each of these factors plays a significant role in the health and fertility of breeding females. For example, deviations from breed standards in body size can lead to complications during pregnancy and whelping, while an inappropriate body condition score may disrupt hormonal balance and reproductive cycles. This review also addresses concerns related to brachycephalic breeds, whose conformation can contribute to respiratory and reproductive issues. Additionally, assessing vertebral and pelvic conformation is crucial to prevent dystocia and other complications during delivery. By systematically evaluating these morphological traits, veterinarians can promote ethical breeding practices that prioritize the welfare and genetic health of both breeding females and their puppies. Therefore, integrating comprehensive morphological evaluations into BSEs is essential for responsible dog breeding management, ultimately supporting better reproductive outcomes and healthier future generations. Full article

Identifying chicken breeds and genders accurately is essential for conserving local breeds and maintaining gender ratios on farms. This study developed a system based on the Swin Transformer that efficiently and accurately classifies chicken breeds and genders. The system incorporates a target detection module to eliminate background noise and employs data augmentation techniques to prevent overfitting. A high-quality dataset, consisting of 10,482 locally captured images representing 13 Chinese native chicken breeds, was created for training and testing the model. The system was evaluated using a custom dataset and compared against popular image classification models, such as ResNet and ViT. Results indicate that the target detection module and data augmentation effectively improved the model’s performance. Additionally, strategies such as increasing the input size appropriately and utilizing pre-trained weights significantly enhanced the model’s accuracy. Interpretability analysis reveals that the system successfully identifies specific chicken body parts across different breeds and genders, aligning with human visual attention and highlighting its effectiveness. This work provides a robust solution for poultry management, aiding in tasks such as breed selection, gender ratio control, and genetic conservation. Furthermore, the methodology and dataset presented in this research provide a foundation for future studies in agricultural computer vision applications. Full article

Vertebral Heart Score (VHS) is one of the commonly used methods for detecting cardiomegaly in dogs. However, this method has diagnostic limitations due to factors such as breed variations, orthopedic disorders, anatomical anomalies, and operator-dependent subjectivity. The aim of this study was to evaluate the diagnostic utility of the Manubrium Heart Score (MHS) as an alternative to VHS in the assessment of cardiomegaly in dogs. A total of 490 dogs were classified and grouped based on body weight and cardiac health status. On the right lateral thoracic radiographs, MHS was calculated as the ratio of manubrium length (ML) to the sum of the long-axis heart length (cLAL) and short-axis heart length (cSAL). Similarly, VHS was determined. A positive correlation between VHS and MHS, as well as between ML and cSAL/cLAL, were observed in all groups except for the group of medium sized dogs with heart diseases. No correlations were found between MHS and LA or the LA/Ao ratio. In pairwise comparisons of VHS and MHS between heart-diseased and healthy dogs, the mean VHS showed a statistically significant difference in heart-diseased dogs (p < 0.001), and not across all groups (p > 0.05). MHS may not consider a useful method as an alternative to VHS. Full article

This article has examined the effects of magnetic fields with intensities of 1 mT, 3 mT, and 5 mT on two species of cichlid fish (family Cichlidae). This study focused specifically on assessing the influence of these magnetic fields on larval development, the survival rate, and the occurrence of deformities in the larvae of the jaguar cichlid (Parachromis managuensis) and the green terror (Andinoacara rivulatus). The analysis of the study results indicates that the effects of magnetic field exposure depend both on its intensity and on the fish species being studied. Magnetic fields, depending on the applied intensity, can influence changes in body size as well as the size of the yolk sac. In jaguar cichlid larvae, increased survival was observed in the groups exposed to the magnetic field; however, this was accompanied by a higher number of deformities compared with the control group. In the case of the green terror, the highest survival rates were recorded in the control group and in the group exposed to a magnetic field of 3 mT, while increased numbers of deformities were also noted in the exposed groups. The obtained results may be of significant importance for ornamental fish aquaculture, where appropriately selected magnetic field parameters could support larval growth and survival, reducing losses in breeding. Full article

The African catfish, Clarias gariepinus, is among the most farmed fish species in Uganda’s rapidly growing aquaculture sub-sector. The enhanced growth performance, increased survival, and resilience to environmental stressors have driven a rising demand among farmers for improved African catfish broodstock and seed. Until recently, most studies of this species have focused on nutrition, physiology, and culture systems, with little known about the genetics, broodstock, and hatchery management of the cultured C. gariepinus populations. This knowledge gap has led to inbreeding depression, resulting in poor seed quality and reduced performance of the broodstock. To enhance catfish aquaculture production, a survey was conducted across multiple catfish hatcheries and farms in Uganda. Using semi-structured questionnaires, the study assessed broodstock management practices, hatchery propagation methods, the suitability of various populations, demographics, challenges, and prospects of hatchery operators. Responses were coded, and descriptive statistics such as frequency, percentages, and means were calculated. Results indicate that there are farmers who continue to source their broodstocks from the natural water bodies in addition to acquiring them from fellow farmers. The estimated effective population size (Ne) for the majority of the respondents was 133.33 and 178.22, with an average breeding coefficient of 0.4% and 0.3%, respectively. There is also a continuous use of shooters (fast-growing cannibalistic fish) by the farmers who hatch and select them to be used as broodstocks later, under the assumption that they have superior genetic traits. The reported hatchability rate was above 70%, with an average survival rate of 60% from larvae to fry. The study identified diseases, inadequate water supply, and electricity as the primary challenges for catfish breeding. While Uganda’s African catfish aquaculture industry is expanding rapidly, certain hatchery practices pose significant risks to its sustainability if not properly addressed. Full article

The roan coat color is described as the dispersion of white hairs within an otherwise solid background color coat. This phenotype is primarily expressed on the body of the horse, with the head and legs exhibiting few to no white hairs. Previous studies mapped the locus for roan to the KIT region and observed linked variants in a small number of breeds. However, utilizing those linked markers to determine the roan genotype in other breeds has seen limited success. In this communication we identify a second roan allele (RN2) which, in conjunction with a previously observed roan allele (RN1) discovered in previous studies, accounts for approximately 74%, or 188 horses, out of a sample size totaling 257 roan horses. These two alleles were present in the non-roan population (N = 3212) at less than 1%, only in horses with light coat color and dilution alleles, likely obscuring the roan phenotype. Future work is required to identify additional alleles responsible for additional roan-type horse coat color phenotypic variation. Full article

A breeding program of Asian seabass (Lates calcarifer, also called barramundi) was established for sustainable aquaculture in Thailand. Estimated breeding values (EBVs) for growth of the base population (G0, 51 families, N = 1655) were evaluated. Fish exhibited either high (HEBV, averaged body weight = 1036.80 ± 250.80 g, N = 133) or low (LEBV, averaged body weight = 294.50 ± 167.20 g, N = 147) growth EBVs, and their parental fish (N = 26) were analyzed by Specific Locus Amplified Fragment Sequencing (SLAF-Seq). An average of 159,769 SLAF tags/sample was generated, covering 13.79-fold of the genome size, and 225,498 SNPs were applied for population genomics. Observed (H_o) and expected (H_e) heterozygosity values were 0.224 and 0.308, 0.178 and 0.246, and 0.184 and 0.305, respectively. Polymorphic information content (PIC) ranged from 0.205–0.251. A selective sweep was performed based on Fst, and nucleotide polymorphism (π) revealed significant differences between allelic contents of growth- and immune-related genes in HEBV and LEBV populations. Kinship analysis revealed that 84.38% of examined fish showed r values < 0.2, and population admixture analysis revealed three subpopulations in HEBV and four subpopulations in LEBV groups. Fish that possessed a single cluster were found in each subgroup of both populations, along with those exhibiting mixed ancestral clusters. This information is critically important for further applications in our ongoing seabass improvement breeding program. Full article

When selecting a habitat, it is optimal for organisms to choose one that maximizes reproductive success through access to high-quality resources, particularly in species that engage in parental care. However, organisms may inadvertently select a habitat for breeding that would initially appear preferential and undamaged, but may, in reality, be detrimental to parent and/or offspring fitness. In this study, we tested whether migratory European Pied Flycatchers (Ficedula hypoleuca) nesting in forest patches affected by outbreaks of the great web-spinning sawfly (Acantholyda posticalis) experienced fitness reductions indicative of an ecological trap, compared to those nesting in unaffected forest patches. After installing nest boxes to attract breeding pairs and potentially combat the outbreak, we found that Flycatchers inhabiting areas with sawfly outbreaks had similar clutch sizes to pairs breeding in unaffected forest patches. Contrarily, the fledgling number and body condition were significantly lower for those nesting in the damaged forests. In providing nest boxes for migrating Flycatcher pairs in forest patches that were subsequently impacted by a pest insect outbreak, an ecological trap arose for those pairs choosing to nest in what appeared to be an unaffected forest at first. Given the inability of breeding pairs to distinguish habitat quality on initial inspection, we suggest that nest boxes be used with caution in areas with unfavorable habitat conditions when attracting migratory birds, given the trends of their declining global numbers. Full article