Berardo de Jesús Rodríguez

Musical exposure in dairy cattle has been associated with potential effects on milk production, behavior, and physiological regulation; however, available evidence remains heterogeneous and potentially affected by biological and environmental confounding. In high-tropical grazing systems, these responses are simultaneously influenced by stress physiology, disease, nutrition, management, climatic variability, and individual adaptation. This review integrated causal inference and graphical epidemiology to develop biologically grounded directed acyclic graphs (DAGs) representing hypothesized causal pathways between musical exposure and milk production, behavior, and heart rate variability (HRV). An analytical narrative synthesis of physiological, ethological, autonomic, and epidemiological evidence was conducted, and three independent DAGs were constructed using DAGitty version 3.1. Variables were classified according to their epidemiological roles. The production DAG identified stress as a major integrative node linking disease, nutrition, reproductive physiology, management, and milk yield. The behavioral DAG highlighted the roles of ecological organization, resource access, social interaction, and environmental instability. The HRV DAG treated HRV as beat-to-beat variation in cardiac intervals that provides a non-invasive index of autonomic nervous system (ANS) modulation, including sympathetic and parasympathetic influences, and indicated that responses may occur through indirect modulation of stress physiology and vagal activity. We conclude that musical interventions should be interpreted as context-dependent sensory exposures rather than isolated causal determinants; the proposed DAGs provide an explicit basis for selecting covariates, avoiding inappropriate adjustment, and designing future studies of dairy cattle welfare and production.

Axolotls ( Ambystoma mexicanum ) are neotenic salamanders widely used as experimental models in regenerative biology, developmental research, toxicology, and pharmacology. Despite their extensive use in laboratory research and conservation programs, standardized necropsy procedures for this species remain limited and poorly documented. The absence of systematic protocols limits the consistency of postmortem examinations and complicates the interpretation of pathological findings in both experimental and diagnostic contexts. Here, we present a detailed and reproducible necropsy protocol for the neotenic axolotl based on 17 systematic necropsies performed under controlled laboratory conditions. The procedure describes step‐by‐step methods for external examination, access to the cranial cavity, exposure of the spinal cord, and systematic exploration of the coelomic cavity. Particular emphasis is placed on anatomical orientation, preservation of organ relationships, and strategies to minimize tissue damage during dissection. The protocol also includes guidelines for tissue sampling, fixation, and transport for downstream laboratory analyses such as histopathology and microbiology. Protocol refinement revealed practical considerations not previously described for this species, including variability in hepatic size and the absence of coelomic fat bodies in examined specimens, which simplified visceral exposure and influenced dissection strategy. These findings highlight the need to adapt necropsy techniques to species‐specific anatomical characteristics. This protocol provides a practical reference for veterinarians, pathologists, and researchers working with A. mexicanum , facilitating standardized postmortem examinations and improving the reliability and reproducibility of diagnostic and research findings in this important amphibian model. © 2026 Wiley Periodicals LLC. Basic Protocol 1 : External examination Basic Protocol 2 : Organs of the head and spinal cord examination Basic Protocol 3 : Organs of the coelomic cavity examination Support Protocol : Collection, preservation and transport of specimens for laboratory analysis

Music has been recognized as an artistic and therapeutic stimulus in humans and other animals. In rodents, most auditory enrichment studies have relied on human-composed music within the human auditory range, overlooking species-specific acoustic perception. Mice communicate mainly in the ultrasonic range (>20 kHz), particularly during courtship, producing structured songs with complex syllables and phrases. To address this gap, we developed and tested a digital ultrasonic music program inspired by murine courtship songs using vocalizations from BALB/c and C57BL/6 strains. Songs were recorded, behaviorally contextualized, and digitally adapted into structured ultrasonic stimuli. Enrichment did not induce anxiogenic effects. In BALB/c mice, ethograms and plus-maze testing revealed increased exploratory behavior in stimulated groups, while C57BL/6 mice showed more variable responses. No adverse effects were observed. This study provides a systematic approach to species-tailored ultrasonic music, generating both behavioral insights and a bioacoustic library that may support replicable protocols in animal enrichment, neuroscience, and welfare research.

Functional veterinary music, defined as music specifically designed in its tempo, rhythm, harmonic structure, and frequency ranges to modulate animal emotional states and behavior, has emerged as an innovative strategy for managing lactating sows. Exposure to functional music in other studies during gestation and lactation has been shown to reduce stereotypic behaviors and increase positive interactions between humans and piglets, with potential indirect benefits for piglet survival and behavior. However, little is known about the effects of functional music applied specifically during lactation, a period in which environmental enrichment is often limited. This study aimed to evaluate the effects of functional music as an enriched auditory stimulus on maternal behavior, pre-weaning piglet mortality, and piglet coping styles during lactation. Three experimental groups were established: (1) Functional Music Group (FMG), animals stimulated with functional music designed and composed for use in pigs; (2) Pink Noise Group (PNG), animals exposed to pink noise as first control; and (3) Non-stimulated Group (NEG), animals not subjected to auditory stimulation as second control. Variables recorded included birth weight, causes of mortality, and several expressions of maternal behavior. The results showed a reduction in crushing-related mortality in the treatment group and behavioral improvements in the sows, suggesting that functional veterinary music may represent a practical enrichment tool for enhancing welfare and improving piglet survival during lactation.

The effects of sound stimulation as a sensorial environmental enrichment for captive animals have been studied. When appropriately implemented for farm animals, it can improve welfare, health, and productivity. Furthermore, there are indications that music can induce positive emotions in non-human animals, similar to humans. Emotion is a functional state of the organism involving both physiological processes, mediated by neuroendocrine regulation, and changes in behavior, affecting various aspects, including contextual perception and welfare. As there is very limited information on non-human animals, the objective of this review is to highlight what is known about these processes from human biological and comparative perspectives and stimulate future research on using music to improve animal welfare.

In intensive swine production systems,, the practice of regrouping unfamiliar pigs is common, often leading to aggressive behavior. Although the effect of different musical genres composed for humans has been evaluated in pigs to mitigate aggression, there have been few attempts to create music specifically for pigs. Here, we assess whether sensory stimulation through music, created by adapting the acoustic parameters in the sound mix, induces changes in the aggressive behaviors of pigs during regrouping. Six litters of 10-week-old piglets were randomly selected and assigned to different treatments. The control group (Group A) received no intervention, while Group B was exposed to music for two continuous hours in the morning and afternoon from the time of regrouping. Group C received musical stimulation for one continuous hour in the morning following regrouping. A significant reduction in the frequency and duration of aggressive behaviors was observed in the groups that received musical stimulation during regrouping. Additionally, social, and individual play behaviors showed a decrease in the musical stimulation groups. These findings provide evidence for the effectiveness of created music as a strategy in reducing aggressive behavior during pig regrouping, which can enhance the welfare of pigs and offer a practical solution for pig producers to minimize aggression and its associated negative impacts.

Plant natural products can attenuate the myonecrosis caused by Bothrops snake venom and their phospholipases A₂ (PLA₂). In this study, we evaluated the effects of two fractions (F4 and F6) from Swietenia macrophylla and purified catechin on the muscle damage caused by a myotoxic PLA₂ from Colombian Bothrops asper venom (BaColPLA₂) in mice and by Bothrops marmoratus venom from Brazil in mouse phrenic nerve-diaphragm muscle (PND) preparations in vitro. Male mice were injected with PLA₂ (50 µg) in the absence or presence of F4, F6, and catechin, in the gastrocnemius muscle and then killed 3, 7, 14, and 28 h later for histopathological analysis of myonecrosis, leukocyte infiltration, and the presence of collagen. Fractions F4 and F6 (500 µg) and catechin (90 µg) significantly reduced the extent of necrosis at all-time intervals. These two fractions and catechin also attenuated the leukocyte infiltration on day 3, as did catechin on day 14. There was medium-to-moderate collagen deposition in all groups up to day 7, but greater deposition on days 14 and 28 in the presence of F6 and catechin. Bothrops marmoratus venom (100 µg/mL) caused slight (~25%) muscle facilitation after 10 min and weak neuromuscular blockade (~64% decrease in contractile activity after a 120-min incubation). Pre-incubation of venom with F4 or F6 abolished the facilitation, whereas catechin, which was itself facilitatory, did not. All three fractions attenuated the venom-induced decrease in muscle contractions. These findings indicate that fractions and catechin from S. macrophylla can reduce the muscle damage caused by Bothrops venom and PLA₂. These fractions or their components could be useful for treating venom-induced local damage.