Animals

17 pages, 440 KB

Open AccessFeature PaperArticle

Effects of Hand-Rearing and Group Size on Chimpanzee (Pan troglodytes) Social Competence in Captivity

by Lindsay E. Murray

Animals 2026, 16(2), 250; https://doi.org/10.3390/ani16020250 (registering DOI) - 14 Jan 2026

The behavior of individual animals reflects both internal states and external context. For captive animals, their early life experiences can influence later adjustment, particularly their social competence. In addition, the way in which they are housed and their current social grouping context are [...] Read more.

The behavior of individual animals reflects both internal states and external context. For captive animals, their early life experiences can influence later adjustment, particularly their social competence. In addition, the way in which they are housed and their current social grouping context are important factors affecting the expression of social skills. Here, the social behavior of 39 chimpanzees (Pan troglodytes) was observed to assess whether differences existed due to how the apes were reared and grouped. Behaviors recorded related specifically to five main components: Sociability, Grooming, Play, Responsibility and Aggression. Chimpanzees in larger groups groomed and played more, while those housed in pairs or trios displayed more and spent more time alone. Mother-reared chimpanzees took more responsibility for soliciting grooming, and interactions between grouping and rearing on chimpanzee agonistic display rates highlighted how both hand- and mother-reared chimpanzees display more if housed in small groups rather than large. Implications for the optimal management and welfare of this highly intelligent and social species are discussed in light of the importance of early life experiences in modulating the impact of current social environment on chimpanzee social profiles. Full article

(This article belongs to the Section Zoo Animals)

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20 pages, 930 KB

Open AccessFeature PaperArticle

Interdisciplinary Tools to Safeguard and Amplify Aquatic Genetic Resource Use: A Foundation for Industrial-Scale Quality Control for Fertilization

by Sarah Bodenstein, E Hu, Zoltan M. Varga and Terrence R. Tiersch

Animals 2026, 16(2), 249; https://doi.org/10.3390/ani16020249 (registering DOI) - 14 Jan 2026

Abstract

Genetic resources are becoming increasingly important in aquatic species, especially in sectors such as aquaculture and biomedical research. These advancements, however, lack standardized methodology to consistently improve efficient use of gametes for fertilization and to eliminate male variation during spawning. This study provides [...] Read more.

Genetic resources are becoming increasingly important in aquatic species, especially in sectors such as aquaculture and biomedical research. These advancements, however, lack standardized methodology to consistently improve efficient use of gametes for fertilization and to eliminate male variation during spawning. This study provides a conceptual basis for generalizable quality control in artificial spawning of aquatic species by using interdisciplinary, industrial-scale tools to calculate a fertilization unit (e.g., the amount of sperm required to reliably fertilize the eggs produced by a female). Blue catfish (Ictalurus furcatus), zebrafish (Danio rerio), and eastern oysters (Crassostrea virginica) were used as diverse representative species. Comparisons among aquatic species were reviewed, fertilization units were defined, and a sensitivity analysis was performed to assess how deviations from the fertilization unit could affect artificial spawning efficiency. Overall, reproductive strategy (e.g., gamete biology) and production setting significantly influenced the fertilization unit. Employing a fertilization unit decreased “wasted” sperm and reduced male variability during spawning. Furthermore, fertilization efficiency dropped significantly when sperm use strayed from the fertilization unit, declining with both underuse and overuse, especially in oysters and catfish. Standardizing gamete use in aquatic species is essential for economic planning and achieving commercial-scale production, especially when investing in selectively bred or cryopreserved sperm. Full article

(This article belongs to the Section Aquatic Animals)

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16 pages, 1121 KB

Open AccessArticle

Evaluation of the Diagnostic Performance and Validation of an AI-Assisted Fluorescence Imaging Device for Fecal Egg Counts Against the Manual McMaster Reference Method in Kiko Male Goats

by Ahmadreza Mirzaei, Alireza Rahmani Shahraki, Fiona P. Maunsell and Brittany N. Diehl

Animals 2026, 16(2), 248; https://doi.org/10.3390/ani16020248 - 14 Jan 2026

Abstract

Gastrointestinal parasites are a major health and economic concern in small ruminants. The classic microscopic approach using the manual McMaster method serves to quantitatively count parasite eggs, which are labor-intensive and prone to variation. Artificial intelligence-based systems (Parasight^®, powered by Fecalsight [...] Read more.

Gastrointestinal parasites are a major health and economic concern in small ruminants. The classic microscopic approach using the manual McMaster method serves to quantitatively count parasite eggs, which are labor-intensive and prone to variation. Artificial intelligence-based systems (Parasight^®, powered by Fecalsight AI™) could provide quicker and more objective alternatives; therefore, independent validation is necessary before clinical implementation. The objective of this study was to evaluate the agreement, classification consistency, and diagnostic performance of Parasight^® relative to the manual McMaster method, with a focus on its suitability as a screening and decision-support tool. Fecal samples from 44 Kiko goats over 3 sampling times were analyzed using both methods, with manual counts performed independently by 2 observers. Agreement between methods was assessed using Lin’s concordance correlation coefficient, Bland–Altman analysis, and Cohen’s Kappa for categorical classification. Diagnostic performance for identifying animals exceeding the clinical treatment threshold (>1000 eggs per gram) was evaluated using receiver operating characteristic (ROC) analysis, and regression modeling was used to characterize associations between methods. Manual observers showed high reliability, confirming the suitability of the McMaster method as a reference. Compared with manual counts, Parasight^® consistently underestimated egg counts, resulting in poor-to-moderate absolute agreement; however, it reliably ranked animals by parasite burden and showed excellent discrimination for identifying animals above the treatment threshold (AUC = 0.90–0.96). Regression analyses further demonstrated linear or curvilinear associations depending on egg counts. Overall, the Parasight^® device reliably captured relative parasite burden but required a lower operational threshold to match manual treatment decisions. Full article

(This article belongs to the Topic AI, Deep Learning, and Machine Learning in Veterinary Science Imaging)

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26 pages, 3312 KB

Open AccessArticle

Effects of Aquatic Plants on Water Quality, Microbial Community, and Fish Behaviors in Newly Established Betta Aquaria

by Yidan Xu, Lixia Li, Yuting Chen, Yue Zhang, Tianyu Niu, Puyi Huang and Longhui Chai

Animals 2026, 16(2), 247; https://doi.org/10.3390/ani16020247 - 14 Jan 2026

Abstract

Maintaining water quality and fish well-being in newly established, small, unfiltered betta (Betta splendens) aquaria is a significant challenge. To improve betta fish breeding and welfare, this study set up four groups: the Sagittaria subulata (S.su) group, the Alternanthera [...] Read more.

Maintaining water quality and fish well-being in newly established, small, unfiltered betta (Betta splendens) aquaria is a significant challenge. To improve betta fish breeding and welfare, this study set up four groups: the Sagittaria subulata (S.su) group, the Alternanthera reineckii (A.re) group, the Wolffia globosa (W.gl) group, and the plant-free (CG) group. We evaluated the effects of aquatic plants on water quality, fish behavior, and microbial community in newly established tanks over 25 days. The results demonstrated that both the dissolved oxygen (DO) and potential of hydrogen (pH) decreased with the experimental duration, while ammonia nitrogen (NH₃-N) increased over time in all groups. Compared to the CG group, all aquatic plants significantly reduced the NH₃-N accumulation. The S.su group exhibited the lowest mean NH₃-N concentration of only 0.14 mg·L⁻¹, which was considerably lower than that of the other groups (p < 0.05). The behavioral analysis revealed that, during the 25-day randomized monitoring period, bettas in the S.su group exhibited the lowest surface breathing, with an average of only 0.36 events per 5 min, which was significantly lower than that of the CG group (p < 0.05). Additionally, the S.su and W.gl groups demonstrated longer average swimming durations than the other groups, suggesting a potential trend toward improved welfare in betta fish. Aquatic plants shaped the microbial diversity and composition within the experimental aquatic system. The W.gl group had the highest microbial diversity, and the A.re and S.su groups enriched Verrucomicrobiota. These results demonstrate the preferential shaping of microbial communities by aquatic plants, suggesting a potential pathway for enhancing water quality. In conclusion, S. subulata demonstrates the greatest benefits under the experimental conditions, making it a more suitable choice for this experiment. Full article

(This article belongs to the Section Aquatic Animals)

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15 pages, 1884 KB

Open AccessArticle

Genomic Characterization and Phylogenetic Relationships of Procypris rabaudi Revealed by Whole-Genome Survey Analysis

by Xiaolu Han, Renhui Luo, Qi Liu, Zengbao Yuan and Wenping He

Animals 2026, 16(2), 246; https://doi.org/10.3390/ani16020246 - 14 Jan 2026

Abstract

Procypris rabaudi, a member of the Cyprinidae family and genus Procypris, has been designated as a national second-class protected wildlife species in China due to a significant decline in its wild populations. Understanding its genomic characteristics and mitochondrial genome structure is [...] Read more.

Procypris rabaudi, a member of the Cyprinidae family and genus Procypris, has been designated as a national second-class protected wildlife species in China due to a significant decline in its wild populations. Understanding its genomic characteristics and mitochondrial genome structure is crucial for germplasm conservation and systematic classification. In this study, we utilized high-throughput sequencing to investigate the genome of P. rabaudi. The genome size was 1.5 Gb, with a heterozygosity rate of 0.44% and 61.47% of repetitive sequences. We identified 1,151,980 simple sequence repeats (SSRs), with mononucleotide repeats being the most abundant at 55.34%. The complete mitochondrial genome was assembled with 16,595 bp length. A phylogenetic tree constructed from 13 mitochondrial protein-coding genes indicated that genus Procypris was most closely related to genus Luciocyprinus and formed a monophyletic group with Cyprinus, Carassioides, and Carassius. Pairwise Sequentially Markovian Coalescent (PSMC) analysis revealed a rapid population expansion prior to the Last Interglacial Period, followed by a decline after reaching its peak during Last Glacial Period. Notably, P. rabaudi exhibited a two-peak demographic pattern during both the Last Glacial Period. These genomic data provide valuable resources for the conservation of P. rabaudi germplasm and for future studies on cyprinid classification and evolution. Full article

(This article belongs to the Special Issue Omics in Economic Aquatic Animals: Second Edition)

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14 pages, 4614 KB

Open AccessArticle

Utilizing an In Vitro Fermentation Model to Assess Probiotics on Eimeria-Disturbed Cecal Microbiome and Metabolome

by Yani Wu, Xueting You, Shuping Huang, Ju Chai, Yongqi Zeng, Haitao Shi and Xi Wang

Animals 2026, 16(2), 245; https://doi.org/10.3390/ani16020245 - 14 Jan 2026

Abstract

Rectifying the microbiome perturbed by Eimeria invasion might alleviate the adverse effects of coccidia on broiler growth. This study employed an in vitro fermentation model to investigate the direct, host-independent effects of two probiotics—Lactobacillus rhamnosus (LR) and Bacillus subtilis (BS)—on the cecal [...] Read more.

Rectifying the microbiome perturbed by Eimeria invasion might alleviate the adverse effects of coccidia on broiler growth. This study employed an in vitro fermentation model to investigate the direct, host-independent effects of two probiotics—Lactobacillus rhamnosus (LR) and Bacillus subtilis (BS)—on the cecal microbiome and metabolome perturbed by Eimeria tenella. Four in vitro fermentation treatments consisted of a healthy control (cecal slurry samples from health broilers), an Eimeria-disturbed control (slurry samples from infected broilers), an LR treatment (Eimeria-infected slurry + 3 × 10⁵ of LR cfu/mL), and a BS treatment (Eimeria-disturbed group + 3 × 10⁵ of BS cfu/mL). 16S rRNA sequencing and metabolomic analysis revealed that Eimeria infection resulted in an increase in microbial alpha diversity, promoted opportunistic pathogens, including Helicobacter and Bacteroides, and suppressed commensals like Lactobacillus, concurrently altering 530 intracellular metabolites. Probiotic supplementation partially restored microbial composition. Notably, LR inoculation rectified 107 metabolites across pathways including galactose metabolism and phosphotransferase systems, primarily affecting membrane phospholipid balance. In contrast, BS addition restored only 64 metabolites, largely related to secondary metabolism. The current in vitro study indicates that LR can directly modulate key metabolic disturbances in a dysbiotic microbiota, while the BS may be more dependent on host-mediated interactions. Full article

(This article belongs to the Section Poultry)

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24 pages, 2154 KB

Open AccessArticle

Evaluation of Two Practical Field Methods for Estimating Operational Overmilking Duration Using Standard Milking-System Sensors

by Alice Uí Chearbhaill, Pablo Silva Boloña, Eoin G. Ryan, Catherine I. McAloon, Martin Browne and John Upton

Animals 2026, 16(2), 244; https://doi.org/10.3390/ani16020244 - 13 Jan 2026

Abstract

The objective of this study was to quantify the method-to-method variation between two widely used field indicators of the end-of-milking vacuum-exposure period (i.e., operational overmilking duration), and to identify cow- and milking-level factors associated with this variation. Operational overmilking was defined using two [...] Read more.

The objective of this study was to quantify the method-to-method variation between two widely used field indicators of the end-of-milking vacuum-exposure period (i.e., operational overmilking duration), and to identify cow- and milking-level factors associated with this variation. Operational overmilking was defined using two approaches: (i) MPC vacuum fluctuation patterns collected via VaDia™ recording devices, and (ii) milk flow curves generated from milking system data, with simulated ACR take-off thresholds ranging from 0.2 to 0.8 kg/min. Seven quarter combinations were analyzed to determine their effect on method-to-method variation. Multivariable modelling was used to investigate the factors which influenced the absolute difference in operational overmilking duration (ADOD) between methods, with larger ADOD indicating greater method-to-method variation. All quarter combinations showed large method-to-method variations. VaDia^TM-derived estimates indicated longer overmilking durations and higher milk flow at the onset of overmilking compared with the milk flow curve approach. Our findings showed that a combination of the rear quarters was significantly associated with the lowest ADOD, and that a combination of the front quarters was significantly associated with the highest ADOD. All other combinations did not differ from each other, indicating that combinations including one front and one rear quarter performed similarly, and that recording all four quarters did not improve agreement between methods within this dataset. Milk flow factors associated with increased ADOD included longer low flow times, longer high flow times, longer machine-on times, and increased yield. Vacuum values associated with increased ADOD included high short milk tube vacuum during the full milking, and high mouthpiece chamber vacuum levels during both the full milking and overmilking periods. High short milk tube vacuum during overmilking was associated with decreased ADOD. Wider teat diameters, longer teat lengths, and increased parity were associated with increased ADOD. These findings indicated that vacuum-based and flow-based indicators of operational overmilking capture different aspects of the end-milking process and should be clearly specified when measuring or reporting overmilking in research or commercial milking systems. Full article

(This article belongs to the Section Animal System and Management)

19 pages, 11838 KB

Open AccessArticle

Transcriptomic Analysis of the Antiviral Responses in Ovine Type II Alveolar Epithelial Cells During Early Stage of Bluetongue Virus Infection

by Yunyi Chen, Nijing Lei, Zhenghao Ye, Shaohua Pu, Shimei Luo, Xianping Ma, Shaoyu Yang, Guanghua Wang, Huaijie Jia and Huashan Yi

Animals 2026, 16(2), 243; https://doi.org/10.3390/ani16020243 - 13 Jan 2026

Abstract

Bluetongue virus (BTV) infects various ruminant species, posing significant threats to animal health and causing substantial economic losses to the livestock industry. Ovine type II alveolar epithelial cells (OAECIIs) play crucial roles in maintaining pulmonary structural integrity and modulating immune responses. Their dysfunction [...] Read more.

Bluetongue virus (BTV) infects various ruminant species, posing significant threats to animal health and causing substantial economic losses to the livestock industry. Ovine type II alveolar epithelial cells (OAECIIs) play crucial roles in maintaining pulmonary structural integrity and modulating immune responses. Their dysfunction is closely associated with lung disease pathogenesis, making them important therapeutic targets. However, OAECIIs’ immunoregulatory functions and early response mechanisms during BTV infection remain unclear. To address this, we analyzed transcriptomic changes in OAECIIs following BTV-1 infection. RNA-seq revealed 1047 and 852 differentially expressed genes (DEGs) at 8 and 12 h post-infection (hpi), respectively, compared to uninfected controls. Bioinformatics analysis showed significant upregulation of nucleic acid-sensing receptors, interferon-stimulating factors, inflammatory mediators, and cytokines during early infection, mediated primarily through type I interferon signaling, TNF signaling, and cytosolic DNA-sensing pathways. We identified MAD5, ZNFX1, cGAS, OAS, PKR and ZBP1 as key pattern recognition receptors in OAECIIs during BTV infection. The IFN-β, MX1/2, RSAD2 and PLSCR1 pathways mediated antiviral responses, while IL-15, CXCL10, CCL2 triggered inflammatory responses, collectively causing structural alterations through AQP1/9 and tight junction protein modulation. These findings provide critical insights into early antiviral mechanisms and cellular structural changes in OAECIIs during BTV infection, establishing a foundation for understanding pneumonia pathogenesis and developing targeted BTV therapies. Full article

(This article belongs to the Topic Advances in Infectious and Parasitic Diseases of Animals)

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9 pages, 825 KB

Open AccessCommunication

Long-Term Immunogenicity and Protection of a rHVT-H9/Y280 Vaccine Against H9N2 Avian Influenza Virus in Commercial Layers with High Maternal Antibodies

by Sang-Won Kim, Jong-Yeol Park, Ji-Eun Son, Kai-Qiong Zheng, Cheng-Dong Yu, Ki-Woong Kim, Won-Bin Jeon, Yu-Ri Choi, Hyung-Kwan Jang, Bai Wei and Min Kang

Animals 2026, 16(2), 242; https://doi.org/10.3390/ani16020242 - 13 Jan 2026

Abstract

The endemicity of H9N2 avian influenza viruses (AIVs), particularly the Y280 lineage, poses persistent challenges to the poultry industry due to the limitations of inactivated vaccines, such as interference by maternally derived antibodies (MDAs) and incomplete suppression of viral replication. This study evaluated [...] Read more.

The endemicity of H9N2 avian influenza viruses (AIVs), particularly the Y280 lineage, poses persistent challenges to the poultry industry due to the limitations of inactivated vaccines, such as interference by maternally derived antibodies (MDAs) and incomplete suppression of viral replication. This study evaluated the immunogenicity and protective efficacy of a novel recombinant turkey herpesvirus vaccine expressing the hemagglutinin gene of H9N2/Y280 (rHVT-H9/Y280) in commercial Hy-Line Brown layers with high-MDA backgrounds. In a comparative challenge study, the rHVT-H9/Y280 vaccine induced complete protection against a homologous Y280 strain challenge at 4 weeks of age, whereas commercial inactivated vaccines failed to completely block replication, showing virus isolation rates of 16.7–25%. Long-term serological monitoring demonstrated that the rHVT-H9/Y280 vaccine elicited a robust humoral response characterized by persistent maintenance of high HI titers (>8.0 log₂) up to 39 weeks post-vaccination. These findings confirm that rHVT-H9/Y280 effectively overcomes MDA interference and provides protection by inhibition of viral replication in layer chickens, making it a promising candidate for the effective control of H9N2 AIV in endemic regions. Full article

(This article belongs to the Special Issue Epidemiology, Surveillance, and Prevention Strategies for Transboundary Animal Diseases)

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13 pages, 657 KB

Open AccessArticle

Evaluation of Pulsed Alternating Wavelength System Lighting on the Welfare Quality and Serotonin Turnover of Commercial Laying Hens Throughout a Lay Cycle

by Brittney J. Emmert, Sara Tonissen, Jenna M. Schober, Gregory S. Fraley and Darrin M. Karcher

Animals 2026, 16(2), 241; https://doi.org/10.3390/ani16020241 - 13 Jan 2026

Abstract

Laying hens require lighting for proper development and reproduction. There is limited research on the effects that lighting types have on birds’ welfare quality. A novel lighting source, Pulsed Alternating Wavelength System (PAWS), is being evaluated in the industry that claims to improve [...] Read more.

Laying hens require lighting for proper development and reproduction. There is limited research on the effects that lighting types have on birds’ welfare quality. A novel lighting source, Pulsed Alternating Wavelength System (PAWS), is being evaluated in the industry that claims to improve birds’ growth rate, decrease age at first egg, and decrease aggressive and nervous behaviors. Understanding how PAWS effects hen’s welfare, both physically and physiologically, is critical if this technology is to be adopted by industry. The project evaluated the effects of two PAWS lighting recipes on neurotransmitter turnover and welfare quality of commercial, conventionally caged laying hens. Three flocks of White leghorn hens (control [fluorescent lights] and two PAWS flocks [PAWS1 and PAWS2]) were sampled from 22 to 70 weeks of age, depending on the flock. The physical welfare of 50 hens per flock and neurotransmitter turnover of 10 hens per flock were assessed at each timepoint. The majority of welfare quality parameters were influenced by age as opposed to lighting type. No differences in dopamine turnover were observed. The hens housed under PAWS1 had reduced serotonin turnover, thus increased serotonin activity, and PAWS2 hens had improved keel bone damage scores; both indicative of improved welfare compared to control hens. The novel lighting may be beneficial to layer welfare, which may lead to increased longevity and productivity. Implementation in cage-free housing should be explored to delve into potential behavioral differences that could further influence welfare outcomes. Full article

(This article belongs to the Section Poultry)

13 pages, 4044 KB

Open AccessCase Report

A Stepwise Integrative Approach to Managing a Refractory Recurrent Cervical Sialocele in a Dog

by Suhyun Lee, Sang-Kun Jang, Duwhan Park and Hwi-Yool Kim

Animals 2026, 16(2), 240; https://doi.org/10.3390/ani16020240 - 13 Jan 2026

Abstract

Recurrent canine cervical sialocele is most often caused by incomplete excision of the mandibular–sublingual gland complex, leading to anatomical distortion and concealment of residual tissue. This case describes the multimodal management of a repeatedly recurrent cervical sialocele in a young, small-breed dog following [...] Read more.

Recurrent canine cervical sialocele is most often caused by incomplete excision of the mandibular–sublingual gland complex, leading to anatomical distortion and concealment of residual tissue. This case describes the multimodal management of a repeatedly recurrent cervical sialocele in a young, small-breed dog following multiple previous revision surgeries. A stepwise bridging strategy was adopted before definitive salvage surgery. Oral phenobarbital was instituted, resulting in partial reduction in fluid accumulation and improved comfort. Ultrasound-guided intracavitary sclerotherapy with OK-432 was then performed, inducing a localized fibrotic response but without durable cure. Final resolution was achieved only after salvage ventral paramedian (VPM) sialoadenectomy, which provided wide exposure for complete excision of deeply concealed sublingual remnant tissue within a fibrotic pseudocapsule. Histology confirmed a cervical sialocele. Transient neuropraxia resolved within 3 weeks, and no recurrence was observed at 6 months postoperatively. To the authors’ knowledge, this is the first report describing intracavitary OK-432 sclerotherapy as part of a staged multimodal strategy for canine cervical sialocele. This case illustrates the feasibility of integrating medical salivary suppression and minimally invasive sclerotherapy as bridging measures before salvage VPM surgery for refractory cervical sialocele. Full article

(This article belongs to the Section Veterinary Clinical Studies)

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28 pages, 1237 KB

Open AccessSystematic Review

Nitrogen Source–Carbohydrate Synchronization in Ruminant Nutrition: A Systematic Review

by Leilson Rocha Bezerra, Juliana Paula Felipe de Oliveira, Antônio Fernando de Melo Vaz, Kevily Henrique de Oliveira Soares de Lucena, Lucas de Souza Barros, Yuri Martins de Andrade Fortunato, Severino Gonzaga Neto, Elzania Sales Pereira, Ronaldo Lopes Oliveira and José Morais Pereira, Filho

Animals 2026, 16(2), 239; https://doi.org/10.3390/ani16020239 - 13 Jan 2026

Abstract

The synchronization between nitrogen sources and carbohydrate fractions represents a critical factor for optimizing microbial protein synthesis and overall ruminant performance. This systematic review, conducted according to PRISMA 2020 guidelines, comprehensively evaluated the interactions between different nitrogen sources (true protein, urea, controlled-release urea, [...] Read more.

The synchronization between nitrogen sources and carbohydrate fractions represents a critical factor for optimizing microbial protein synthesis and overall ruminant performance. This systematic review, conducted according to PRISMA 2020 guidelines, comprehensively evaluated the interactions between different nitrogen sources (true protein, urea, controlled-release urea, and bypass amino acids) and carbohydrate fractions (rapidly degrading soluble, slowly degrading soluble, fibrous, non-fibrous, and Van Soest fractions) in ruminant nutrition. A comprehensive search across PubMed, ScienceDirect, Web of Science, and Scopus databases identified 1855 records, of which 164 studies met the eligibility criteria for qualitative synthesis and 89 for quantitative meta-analysis. The review reveals that synchronization effectiveness varies significantly depending on the nitrogen source–carbohydrate combination, with controlled-release urea showing superior synchrony with slowly degrading carbohydrates, while conventional urea performs better with rapidly degrading sources. Meta-analytical results indicate that optimal nitrogen–carbohydrate synchronization can improve microbial protein synthesis by 18–34%, reduce urinary nitrogen excretion by 12–28%, and enhance feed efficiency by 8–15%. These findings provide evidence-based recommendations for precision nutrition strategies in ruminant production systems. Full article

(This article belongs to the Section Animal Nutrition)

10 pages, 648 KB

Open AccessCommunication

How Dairy Cows Are Culled from Freestall-Housed Dairy Herds in Wisconsin

by Kaitlin I. Buterbaugh, Thomas B. Naze and Nigel B. Cook

Animals 2026, 16(2), 238; https://doi.org/10.3390/ani16020238 - 13 Jan 2026

Abstract

Efforts to improve efficiency and profitability on dairy farms have renewed focus on how culling practices affect herd sustainability and economic outcomes. This study surveyed decision-makers on 60 high-producing, freestall-housed dairy farms in Wisconsin, with a mean (SD) turnover rate of 36.0 (8.0)%. [...] Read more.

Efforts to improve efficiency and profitability on dairy farms have renewed focus on how culling practices affect herd sustainability and economic outcomes. This study surveyed decision-makers on 60 high-producing, freestall-housed dairy farms in Wisconsin, with a mean (SD) turnover rate of 36.0 (8.0)%. Using a structured questionnaire, we examined herd management, culling criteria, and motivations. Most farms (93%) used on-farm management systems to guide culling, yet only 48% used designated reports, relying instead on individual cow records. Milk production, infertility, and somatic cell count were the top culling criteria, with high milk yield cited as the most difficult factor in removal decisions. While 54% recorded the most obvious reason for culling, only 7% documented multiple causes. Cull cows were typically transported by third parties; 80% farms sent cows directly to slaughter, while 52% sent them to auction. One-third of farms sold cows for continued dairy use. Euthanasia was performed on 93% of farms, mostly by employees, with minimal veterinary input. The study aimed to investigate producer perspectives on the culling decision-making process on commercial dairy farms. The findings highlight opportunities for improved veterinary involvement and the use of structured herd-level reports to support more strategic culling decisions. Full article

(This article belongs to the Section Animal System and Management)

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30 pages, 8192 KB

Open AccessArticle

Structural Insights into the Receptor-Binding Domain of Bat Coronavirus HKU5-CoV-2: Implications for Zoonotic Transmission via ACE2

by Manal A. Babaker, Nariman Sindi, Othman Yahya Alyahyawy, Ehssan Moglad, Mohieldin Elsayid, Thamir M. Eid, Mohamed Eltaib Elmobark and Hisham N. Altayb

Animals 2026, 16(2), 237; https://doi.org/10.3390/ani16020237 - 13 Jan 2026

Abstract

The zoonotic potential of bat coronaviruses, especially HKU5, is a significant issue because of their capacity to utilize human angiotensin-converting enzyme 2 (ACE2) as a receptor for cellular entry. This study offers structural insights into the binding kinetics of HKU5 (Bat Merbecovirus HKU5) [...] Read more.

The zoonotic potential of bat coronaviruses, especially HKU5, is a significant issue because of their capacity to utilize human angiotensin-converting enzyme 2 (ACE2) as a receptor for cellular entry. This study offers structural insights into the binding kinetics of HKU5 (Bat Merbecovirus HKU5) receptor-binding domain (RBD) spike protein with human ACE2 through a multiscale computational method. This study employed structural modeling, 300-nanosecond (ns) molecular dynamics (MD) simulations, alanine-scanning mutagenesis, and computational peptide design to investigate ACE2 recognition by the HKU5 RBD and its interactions with peptides. The root mean square deviation (RMSD) investigation of HKU5–ACE2 complexes indicated that HKU5 exhibited greater flexibility than SARS-CoV-2, with RMSD values reaching a maximum of 1.2 nm. Free energy analysis, Molecular Mechanics/Generalized Born Surface Area (MM/GBSA), indicated a more robust binding affinity of HKU5 to ACE2 (ΔG_Total = −21.61 kcal/mol) in contrast to SARS-CoV-2 (ΔG_Total = −5.82 kcal/mol), implying that HKU5 binding with ACE2 had higher efficiency. Additionally, a peptide was designed from the ACE2 interface, resulting in the development of 380 single-site mutants by mutational alterations. The four most promising mutant peptides were selected for 300-nanosecond (ns) MD simulations, subsequently undergoing quantum chemical calculations (DFT) to evaluate their electronic characteristics. MM/GBSA of −37.83 kcal/mol indicated that mutant-1 exhibits the most favorable binding with HKU5, hence potentially inhibiting ACE2 interaction. Mutant-1 formed hydrogen bonds involving Glu74, Ser202, Ser204, and Asn152 residues of HKU5. Finally, QM/MM calculations on the peptide–HKU5 complexes showed the most favorable ΔE_interaction of −170.47 (Hartree) for mutant-1 peptide. These findings offer a thorough comprehension of receptor-binding dynamics and are crucial for evaluating the zoonotic risk associated with HKU5-CoV and guiding the design of receptor-targeted antiviral treatments. Full article

(This article belongs to the Special Issue Zoonotic Diseases: Etiology, Diagnosis, Surveillance and Epidemiology: Second Edition)

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26 pages, 2421 KB

Open AccessReview

Fatty Liver in Fish: Metabolic Drivers, Molecular Pathways and Physiological Solutions

by Xiyu Xie, Chaoyang Zhang, Ilham Zulfahmi, Esau Mbokane and Quanquan Cao

Animals 2026, 16(2), 236; https://doi.org/10.3390/ani16020236 - 13 Jan 2026

Abstract

Fatty liver in fish is characterized by excessive lipid accumulation, driven by factors such as inflammation, oxidative stress, and the overexpression of lipid-related genes. This condition can lead to metabolic dysfunction and reduced disease resistance, resulting in growth disorders and even mortality. Increasing [...] Read more.

Fatty liver in fish is characterized by excessive lipid accumulation, driven by factors such as inflammation, oxidative stress, and the overexpression of lipid-related genes. This condition can lead to metabolic dysfunction and reduced disease resistance, resulting in growth disorders and even mortality. Increasing incidence of fatty liver is closely linked to environmental conditions and feeding practices, posing significant challenges to the aquaculture industry. This paper offers a comprehensive overview of hepatic steatosis, with a particular emphasis on fish species. Through a detailed review of various scholarly works, this paper seeks to identify common patterns, emerging trends, and measurable correlations, highlighting the critical importance of understanding this complex relationship. The study of fatty liver is conducted across three dimensions: influencing factors, underlying mechanisms, and potential solutions. Currently, numerous factors contribute to the development of fatty liver, such as feed composition and environmental temperature. On a mechanistic level, the research explores lipid accumulation, inflammation, oxidative stress, and related processes. Furthermore, the paper suggests various solutions and preventive strategies, including considering environmental adaptability during animal migration, employing genetic enhancement techniques, modifying feeding practices, investigating the Nrf2 pathway, and utilizing rapamycin. These findings have significant implications for fisheries management and aquaculture practices, providing valuable insights to enhance sustainability in the industry. Full article

(This article belongs to the Special Issue Developments in Environmental Physiology, Nutrition Physiology, and Immunity Mechanisms of Aquatic Animals)

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14 pages, 760 KB

Open AccessArticle

Two-Generation Genetic Evaluation of Female Reproductive Performance in Pacific White Shrimp (Penaeus vannamei) Under SPF Conditions

by Jiaqi Yu, Jie Kong, Sheng Luan, Jiawang Cao, Mianyu Liu, Kun Luo, Jian Tan, Ping Dai, Zhaoxin Wang, Juan Sui and Xianhong Meng

Animals 2026, 16(2), 235; https://doi.org/10.3390/ani16020235 - 13 Jan 2026

Abstract

Reproductive inefficiency remains a major constraint in Penaeus vannamei hatcheries due to high rates of non-spawning females. This study presents the first two-generational quantitative genetic analysis of female reproductive performance under standardized SPF (Specific Pathogen-Free) conditions. A total of 986 females across two [...] Read more.

Reproductive inefficiency remains a major constraint in Penaeus vannamei hatcheries due to high rates of non-spawning females. This study presents the first two-generational quantitative genetic analysis of female reproductive performance under standardized SPF (Specific Pathogen-Free) conditions. A total of 986 females across two generations (2021–2022) from 198 full-sib and 68 half-sib families were evaluated. Traits analyzed included spawning frequency (SF), mean spawning interval (MSI), number of eggs laid for the first time (NE1), average spawning (AS), total spawning (TS), and spawning success (SS). Heritability estimates for SF, SS, and TS were moderate (0.30 ± 0.06, 0.23 ± 0.06 and 0.28 ± 0.07, respectively), while MSI, NE1, and AS showed low heritability (0.10–0.16). When analyzed separately by year, heritability estimates declined substantially for most traits in the second generation. Strong positive genetic correlations were observed between SF, MSI, NE1, AS, and TS, with pairwise estimates ranging from 0.82 to 0.99, indicating that these traits are under shared genetic control. Despite not being direct selection objects, all reproductive traits exhibited relative genetic progress (246–488% per generation), which is attributable to the high selection intensity applied to the parental generation. Our findings provide a robust foundation for integrating reproductive performance into breeding programs for P. vannamei, particularly under biosecurity and commercial feed-dominated conditions. Full article

(This article belongs to the Section Aquatic Animals)

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24 pages, 1256 KB

Open AccessArticle

Non-Invasive Assessment of Adrenal Activity in the Subterranean Rodent Ctenomys talarum in Field and Laboratory Conditions

by Roxana Zenuto, Valentina Brachetta, María Celina Carrizo, María Sol Fanjul and Cristian Eric Schleich

Animals 2026, 16(2), 234; https://doi.org/10.3390/ani16020234 - 13 Jan 2026

Abstract

The endocrine stress response is a valuable tool for evaluating how organisms cope with environmental challenges. However, selecting an appropriate matrix for measuring glucocorticoids (GCs) requires careful consideration of sample quality and accessibility. This study reveals that blood sampling affects plasma cortisol levels [...] Read more.

The endocrine stress response is a valuable tool for evaluating how organisms cope with environmental challenges. However, selecting an appropriate matrix for measuring glucocorticoids (GCs) requires careful consideration of sample quality and accessibility. This study reveals that blood sampling affects plasma cortisol levels in the subterranean rodent Ctenomys talarum, with the effect being reversed shortly thereafter. To facilitate a non-invasive approach, an enzyme-linked immunosorbent assay (EIA) that had previously been validated for measuring plasma cortisol in C. talarum was evaluated to measure adrenocortical activity by analyzing fecal glucocorticoid metabolites (FGCs). Using this assay, we monitored the stress response during wild capture, transport to captivity, adrenocorticotropic hormone (ACTH) stimulation, and immobilization. This showed that FGC levels accurately reflect adrenal activation in these contexts. We also documented a relationship between reproductive seasonality and FGCs. Finally, we provide evidence for a relationship between adrenal activity and behavior. Our results suggest that when considering plasma GCs for the assessment of acute stress, it is crucial to understand the magnitude and timing of the effects of blood sampling on the stress state of organisms. The validation of FGC measurement in C. talarum provides a new option for advancing ecophysiological studies in both the wild and captivity. Full article

(This article belongs to the Special Issue Wild Animal Welfare: Science, Ethics and Law)

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17 pages, 557 KB

Open AccessArticle

Effects of Dietary Salt and Boric Acid on Milk Quality in Savak Akkaraman Sheep

by Pelin Beyazgül, Selçukhan Akarsu, Yasin Baykalir and Ülkü Gülcihan Şimşek

Animals 2026, 16(2), 233; https://doi.org/10.3390/ani16020233 - 13 Jan 2026

Abstract

This study evaluated the effects of varying dietary salt and boric acid addition doses on the milk quality of Savak Akkaraman sheep. A total of 120 animals were as-signed to six treatment groups (n = 20): control (C), rock salt (S; 10 [...] Read more.

This study evaluated the effects of varying dietary salt and boric acid addition doses on the milk quality of Savak Akkaraman sheep. A total of 120 animals were as-signed to six treatment groups (n = 20): control (C), rock salt (S; 10 g/day), boric acid 20 mg/day (B20), boric acid 40 mg/day (B40), BS20 (20 mg boric acid + 10 g/day rock salt), and BS40 (40 mg boric acid + 10 g/day rock salt). All analyses were performed in duplicate on six samples, taken on days 30 and 35 following the administration of the additives. Physicochemical analyses only showed significant variation in milk pH (p = 0.006), while acidity, dry matter, and ash remained unaffected. Strong positive correlations were found among protein, lactose, salt, and density (r > 0.95; p < 0.001). Coagulation times differed widely, with the longest being observed in BS20 (995.03 s) and the shortest in BS40 (141.73 s). Among mineral parameters, only selenium levels differed significantly between the treatment groups (p < 0.05). No significant differences were found for fat, solids-not-fat, lactose, freezing point, or electrical conductivity. Importantly, boron addition had a significant influence on total casein content (p < 0.001). Overall, dietary rock salt and boric acid did not markedly alter the basic milk composition but produced notable physicochemical changes, particularly in coagulation behavior and casein levels, which may influence the technological properties of sheep milk. Full article

(This article belongs to the Special Issue Feed Additives in Animal Nutrition)

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26 pages, 385 KB

Open AccessReview

Mapping the Kinase Inhibitor Landscape in Canine Mammary Carcinoma: Current Status and Future Opportunities

by Małgorzata Chmielewska-Krzesińska

Animals 2026, 16(2), 232; https://doi.org/10.3390/ani16020232 - 13 Jan 2026

Abstract

Background: Canine mammary carcinoma (CMC) is the most common malignant tumour in female dogs and, due to its similarities, is a valuable comparative model for human breast cancer. Kinase inhibitors have revolutionised the treatment of human breast cancer; their use in veterinary [...] Read more.

Background: Canine mammary carcinoma (CMC) is the most common malignant tumour in female dogs and, due to its similarities, is a valuable comparative model for human breast cancer. Kinase inhibitors have revolutionised the treatment of human breast cancer; their use in veterinary oncology remains marginal. Aim: This review summarises the current knowledge of kinase signalling pathways in CMC and assesses which kinase inhibitors approved for human use have potential in veterinary medicine. Methods: A systematic search of the PubMed database from 1985 to 2025 was performed, focusing on kinase-targeted therapies in both human and canine mammary carcinomas. Data were categorised according to molecular target, clinical approval status, and available preclinical or clinical veterinary evidence. Results: Key molecular pathways targeted by kinase inhibitors are conserved across species, supporting translational opportunities. In vitro studies demonstrate that palbociclib, alpelisib, everolimus, and lapatinib inhibit growth and signalling in CMC cell lines. Clinical trials have not been conducted. Conclusions: Approved kinase inhibitors for human use have untapped therapeutic potential in veterinary oncology. Translational research, including xenograft and organoid models, followed by clinical trials in dogs, is required. Gaining this knowledge could lead to targeted treatment for dogs while advancing comparative understanding of mammary cancer biology across species. Full article

(This article belongs to the Special Issue Tumors in Companion Animals: Detection, Diagnosis, Prognosis and Treatment)

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