A systematic review of the development and application of home cage monitoring in laboratory mice and rats.

BACKGROUND: Traditionally, in biomedical animal research, laboratory rodents are individually examined in test apparatuses outside of their home cages at selected time points. However, the outcome of such tests can be influenced by various factors and valuable information may be missed when the animals are only monitored for short periods. These issues can be overcome by longitudinally monitoring mice and rats in their home cages. To shed light on the development of home cage monitoring (HCM) and the current state-of-the-art, a systematic review was carried out on 521 publications retrieved through PubMed and Web of Science. RESULTS: Both the absolute (~ × 26) and relative (~ × 7) number of HCM-related publications increased from 1974 to 2020. There was a clear bias towards males and individually housed animals, but during the past decade (2011-2020), an increasing number of studies used both sexes and group housing. In most studies, animals were kept for short (up to 4 weeks) time periods in the HCM systems; intermediate time periods (4-12 weeks) increased in frequency in the years between 2011 and 2020. Before the 2000s, HCM techniques were predominantly applied for less than 12 h, while 24-h measurements have been more frequent since the 2000s. The systematic review demonstrated that manual monitoring is decreasing in relation to automatic techniques but still relevant. Until (and including) the 1990s, most techniques were applied manually but have been progressively replaced by automation since the 2000s. Independent of the year of publication, the main behavioral parameters measured were locomotor activity, feeding, and social behaviors; the main physiological parameters were heart rate and electrocardiography. External appearance-related parameters were rarely examined in the home cages. Due to technological progress and application of artificial intelligence, more refined and detailed behavioral parameters have been investigated in the home cage more recently. CONCLUSIONS: Over the period covered in this study, techniques for HCM of mice and rats have improved considerably. This development is ongoing and further progress as well as validation of HCM systems will extend the applications to allow for continuous, longitudinal, non-invasive monitoring of an increasing range of parameters in group-housed small rodents in their home cages.

The Rise of Three Rs Centres and Platforms in Europe.

Public awareness and discussion about animal experiments and replacement methods has greatly increased in recent years. The term 'the Three Rs', which stands for the Replacement, Reduction and Refinement of animal experiments, is inseparably linked in this context. A common goal within the Three Rs scientific community is to develop predictive non-animal models and to better integrate all available data from in vitro, in silico and omics technologies into regulatory decision-making processes regarding, for example, the toxicity of chemicals, drugs or food ingredients. In addition, it is a general concern to implement (human) non-animal methods in basic research. Toward these efforts, there has been an ever-increasing number of Three Rs centres and platforms established over recent years - not only to develop novel methods, but also to disseminate knowledge and help to implement the Three Rs principles in policies and education. The adoption of Directive 2010/63/EU on the protection of animals used for scientific purposes gave a strong impetus to the creation of Three Rs initiatives, in the form of centres and platforms. As the first of a series of papers, this article gives an overview of the European Three Rs centres and platforms, and their historical development. The subsequent articles, to be published over the course of ATLA's 50th Anniversary year, will summarise the current focus and tasks as well as the future and the plans of the Three Rs centres and platforms. The Three Rs centres and platforms are very important points of contact and play an immense role in their respective countries as 'on the ground' facilitators of Directive 2010/63/EU. They are also invaluable for the widespread dissemination of information and for promoting implementation of the Three Rs in general.

The Current Status and Work of Three Rs Centres and Platforms in Europe.

The adoption of Directive 2010/63/EU on the protection of animals used for scientific purposes has given a major push to the formation of Three Rs initiatives in the form of centres and platforms. These centres and platforms are dedicated to the so-called Three Rs, which are the Replacement, Reduction and Refinement of animal use in experiments. ATLA's 50th Anniversary year has seen the publication of two articles on European Three Rs centres and platforms. The first of these was about the progressive rise in their numbers and about their founding history; this second part focuses on their current status and activities. This article takes a closer look at their financial and organisational structures, describes their Three Rs focus and core activities (dissemination, education, implementation, scientific quality/translatability, ethics), and presents their areas of responsibility and projects in detail. This overview of the work and diverse structures of the Three Rs centres and platforms is not only intended to bring them closer to the reader, but also to provide role models and show examples of how such Three Rs centres and platforms could be made sustainable. The Three Rs centres and platforms are very important focal points and play an immense role as facilitators of Directive 2010/63/EU 'on the ground' in their respective countries. They are also invaluable for the wide dissemination of information and for promoting the implementation of the Three Rs in general.

Creating Veterinary Public Health Online Cases by Students for Students.

Online-based processing of case reports is often used and well accepted in veterinary medical education. However, lecturers usually develop cases from their own point of view, without input from students. In order to give students the chance to create online cases for students, an elective course Creative Workshop Case Creation, was held three times between 2017 and 2019 at the Faculty of Veterinary Medicine, Freie Universität Berlin. During this course, students created cases based on animal welfare and epizootics issues through a problem-based blended learning approach. In this approach, students worked on an assigned veterinary public health problem and actively solved it in small groups in class and then used the issue as the basis to create cases for their fellow students. The cases were implemented in interdisciplinary lectures, which are mandatory for every student in semesters six to eight. After taking these classes, fellow students evaluated one of these cases, specifically, on animal welfare and another one on epizootics. Evaluations showed these cases were received well. Moreover, we received excellent feedback from students participating in the elective course, and working with a proactive and motivated group of six students throughout the course was a very productive experience. The course made it possible to create cases that are more accurately tailored to the needs of students. The students' good ideas and preparatory work also saved time in the preparation of cases for lecturers.

Molecular MR-Imaging for Noninvasive Quantification of the Anti-Inflammatory Effect of Targeting Interleukin-1ß in a Mouse Model of Aortic Aneurysm.

BACKGROUND: Molecular-MRI is a promising imaging modality for the assessment of abdominal aortic aneurysms (AAAs). Interleukin-1ß (IL-1ß) represents a new therapeutic tool for AAA-treatment, since pro-inflammatory cytokines are key-mediators of inflammation. This study investigates the potential of molecular-MRI to evaluate therapeutic effects of an anti-IL-1ß-therapy on AAA-formation in a mouse-model. METHODS: Osmotic-minipumps were implanted in apolipoprotein-deficient-mice (N = 27). One group (Ang-II+01BSUR group, n = 9) was infused with angiotensin-II (Ang-II) for 4 weeks and received an anti-murine IL-1ß-antibody (01BSUR) 3 times. One group (Ang-II-group, n = 9) was infused with Ang-II for 4 weeks but received no treatment. Control-group (n = 9) was infused with saline and received no treatment. MR-imaging was performed using an elastin-specific gadolinium-based-probe (0.2 mmol/kg). RESULTS: Mice of the Ang-II+01BSUR-group showed a lower aortic-diameter compared to mice of the Ang-II-group and control mice (p < 0.05). Using the elastin-specific-probe, a significant decrease in elastin-destruction was observed in mice of the Ang-II+01BSUR-group. In vivo MR-measurements correlated well with histopathology (y = 0.34x-13.81, R2 = 0.84, p < 0.05), ICP-MS (y = 0.02x+2.39; R2 = 0.81, p < 0.05) and LA-ICP-MS. Immunofluorescence and western-blotting confirmed a reduced IL-1ß-expression. CONCLUSIONS: Molecular-MRI enables the early visualization and quantification of the anti-inflammatory-effects of an IL-1ß-inhibitor in a mouse-model of AAAs. Responders and non-responders could be identified early after the initiation of the therapy using molecular-MRI.

Animal-based welfare indicators for dairy cows and their validity and practicality: a systematic review of the existing literature.

Animal welfare is of increasing importance, with consumers preferring animal products made with ethical practices due to growing awareness. This shift highlights the need for reliable methods to evaluate welfare. This systematic review aims to assess the validity of current animal-based welfare indicators for dairy cows to aid farmers and agricultural professionals in evaluating and improving welfare amidst the lack of a clear legislative definition. The literature search spanned five databases: CAB Direct, PubMed, Scopus, Google Scholar and Livivo, covering publications in English and German from 2011 to 2021. Specific search terms were employed, and abstracts were screened for relevance. Publications were categorized based on exclusion criteria, with a final verification process conducted by three independent scientists. Research highlights correlations between welfare measures, farm characteristics and innovative indicators like hair cortisol concentration. Farming systems and housing methods significantly affect welfare, with pasture-based systems generally resulting in reduced lameness and improved behavior. Proper housing design and management practices are important, as they influence indicators like lameness and cleanliness. Heart rate variability and heart rate monitoring provide insights into dairy cow stress levels during milking and other stressors, making them valuable for welfare assessment. Biomarker research emphasizes the need to balance productivity and health in breeding strategies, as high milk production alone does not indicate good welfare. Behavioral studies and the human-animal relationship are key to understanding welfare. Precision Livestock Farming offers real-time assessment capabilities, although validation is needed. Stress physiology is complex, and while cortisol measurement methods are promising, further research is necessary. Assessment tools like the Animal Needs Index and routine herd data analysis are valuable for identifying welfare concerns. Key findings highlight the WQ® protocol's effectiveness and versatility, the challenge of its time demands, and the DCF protocol's promise for more practical and efficient welfare assessments. Commercial animal welfare audits should prioritize easily observable indicators and herd records due to logistical constraints in measuring biomarkers or heart rate variability. This focus on easily accessible indicators, such as body condition score, lameness, claw health, cleanliness, and somatic cell count allows effective welfare assessments, enabling prompt action to enhance wellbeing.

Evaluating rearing behaviour as a model-specific pain indicator in mouse osteotomy models.

To assess pain in mouse models of bone fractures, currently applied assessment batteries use combinations of clinical signs with spontaneous behaviours and model-specific behaviours, including walking and weight-bearing behaviour. Rearing behaviour - an upright position on the hindlimbs - has a motivational and an ambulatory component. Thus, rearing behaviour might have the potential to be an indicator for model-specific pain in mouse fracture models. To date, the assessment of rearing behaviour in bone fracture models using mice is only scarcely described. In this study, we aimed to determine whether the duration of rearing behaviour is affected by osteotomy of the femur in male and female C57BL/6N mice with external fixation (rigid vs. flexible) and could be an additional sign for model-specific pain, such as the presence of limping. Rearing duration was significantly decreased after osteotomy in male and female mice at 24 h, 48 h and 72 h, but was not affected by anaesthesia/analgesia alone. In male mice, the relative rearing duration increased over 72 h (both fixations) and at 10 days in the rigid fixation group but remained significantly lower in the flexible fixation group. In contrast, in female mice, no increase in rearing duration was observed within 72 h and at 10 days post-osteotomy, independent of the fixation. We did not identify any association between relative rearing time and presence or absence of limping. In summary, our results do not provide sufficient evidence that altered rearing behaviour might be an indicative sign for pain in this model.

Lockbox enrichment facilitates manipulative and cognitive activities for mice.

Background: Due to the lack of complexity and variety of stimuli, conventional housing conditions of laboratory mice do not allow these animals to fully express their behavioral repertoire, including manipulative and cognitive activities. Therefore, we designed mechanical puzzles, so-called lockboxes, for mice that can be provided in their home cages. We investigated the impact of the lockbox enrichment on their phenotype and affective state when compared to conventional housing (CH) and super-environmental enrichment (SEE). Methods: Young adult female C57BL/6JCrl mice were examined before and after 2-month exposure to the different types of enrichment in a phenotyping test battery, including tests for trait and state anxiety-related behavior, calorimetric measurements, body weight measurements, the analysis of stress hormone metabolite concentrations, and sequential problem-solving abilities with a novel lockbox. At the end of the study, adrenal gland weights were determined and pathohistological evaluation was performed. For all continuous variables, the relative variability was calculated. Results: While the different types of enrichment affected trait anxiety-related behavior, neither state anxiety-related behavior nor physiological variables (i.e., bodyweight, resting metabolic rate, stress hormone metabolite concentrations, adrenal gland weights) were influenced. LE improved sequential problem-solving (i.e., solving novel lockboxes) when compared to SEE. Regardless of the housing condition, the relative variability increased in most variables over time, although the coefficient of variation decreased for some variables, especially in animals with access to LE. There was no evidence of toxicopathological effects associated with the material from which the lockboxes were made. Conclusions: All lockboxes are available as open-source tool. LE revealed beneficial effects on the affective state of laboratory mice and their performance in solving novel lockboxes. Neither relevant phenotype of the mice nor reproducibility of the data were compromised by LE, similar to SEE. The lockboxes may also be used as novel approach for assessing cognition in mice.

AT2-receptor stimulation enhances axonal plasticity after spinal cord injury by upregulating BDNF expression.

It is widely accepted that the angiotensin AT2-receptor (AT2R) has neuroprotective features. In the present study we tested pharmacological AT2R-stimulation as a therapeutic approach in a model of spinal cord compression injury (SCI) in mice using the novel non-peptide AT2R-agonist, Compound 21 (C21). Complementary experiments in primary neurons and organotypic cultures served to identify underlying mechanisms. Functional recovery and plasticity of corticospinal tract (CST) fibers following SCI were monitored after application of C21 (0.3mg/kg/dayi.p.) or vehicle for 4 weeks. Organotypic co-culture of GFP-positive entorhinal cortices with hippocampal target tissue served to evaluate the impact of C21 on reinnervation. Neuronal differentiation, apoptosis and expression of neurotrophins were investigated in primary murine astrocytes and neuronal cells. C21 significantly improved functional recovery after SCI compared to controls, and this significantly correlated with the increased number of CST fibers caudal to the lesion site. In vitro, C21 significantly promoted reinnervation in organotypic brain slice co-cultures (+50%) and neurite outgrowth of primary neurons (+25%). C21-induced neurite outgrowth was absent in neurons derived from AT2R-KO mice. In primary neurons, treatment with C21 further induced RNA expression of anti-apoptotic Bcl-2 (+75.7%), brain-derived neurotrophic factor (BDNF) (+53.7%), the neurotrophin receptors TrkA (+57.4%) and TrkB (+67.9%) and a marker for neurite growth, GAP43 (+103%), but not TrkC. Our data suggest that selective AT2R-stimulation improves functional recovery in experimental spinal cord injury through promotion of axonal plasticity and through neuroprotective and anti-apoptotic mechanisms. Thus, AT2R-stimulation may be considered for the development of a novel therapeutic approach for the treatment of spinal cord injury.

Rumination Detection in Sheep: A Systematic Review of Sensor-Based Approaches.

The use of sensors to analyze behavior in sheep has gained increasing attention in scientific research. This systematic review aims to provide an overview of the sensors developed and used to detect rumination behavior in sheep in scientific research. Moreover, this overview provides details of the sensors that are currently commercially available and describes their suitability for sheep based on the information provided in the literature found. Furthermore, this overview lists the best sensor performances in terms of achieved accuracy, sensitivity, precision, and specificity in rumination detection, detailing, when applicable, the sensor position and epoch settings that were used to achieve the best results. Challenges and areas for future research and development are also identified. A search strategy was implemented in the databases PubMed, Web of Science, and Livivo, yielding a total of 935 articles. After reviewing the summaries of 57 articles remaining following filtration (exclusion) of repeated and unsuitable articles, 17 articles fully met the pre-established criteria (peer-reviewed; published between 2012 and 2023 in English or German; with a particular focus on sensors detecting rumination in sheep) and were included in this review. The guidelines outlined in the PRISMA 2020 methodology were followed. The results indicate that sensor-based systems have been utilized to monitor and analyze rumination behavior, among other behaviors. Notably, none of the sensors identified in this review were specifically designed for sheep. In order to meet the specific needs of sheep, a customized sensor solution is necessary. Additionally, further investigation of the optimal sensor position and epoch settings is necessary. Implications: The utilization of such sensors has significant implications for improving sheep welfare and enhancing our knowledge of their behavior in various contexts.

The implementation of tunnel handling in a mouse breeding facility revealed strain-specific behavioural responses.

As a step towards implementing non-aversive handling techniques at a big mouse breeding facility in Germany, tunnel handling was introduced in a breeding unit comprising three inbred mouse strains. To assess whether tunnel handling would be feasible for the animal technicians in their everyday work and beneficial for the mice when being handled during weekly cage change only, the behaviour of tunnel- and tail-handled animals of both sexes was examined before, during and after the handling events over a period of nine weeks. Moreover, the time expenditure was compared between both handling techniques. It was possible to use the tunnel in all three mouse strains. However, the impact of the handling techniques on the behavioural parameters investigated in the present study were strain-specific. All behavioural parameters suggested that NZW mice benefited the most from tunnel handling. The results obtained from Hello Kitty and WNK mice were ambiguous, which may suggest that a brief handling session during the cage clean may have not been sufficient to habituate them to the process of handling. It took the animal technicians approximately 3 seconds longer per mouse when using a tunnel. The strain-specific results should encourage researchers to share their experiences with non-aversive handling techniques in different mouse strains, for example, along with their research articles.

Challenges and advanced concepts for the assessment of learning and memory function in mice.

The mechanisms underlying the formation and retrieval of memories are still an active area of research and discussion. Manifold models have been proposed and refined over the years, with most assuming a dichotomy between memory processes involving non-conscious and conscious mechanisms. Despite our incomplete understanding of the underlying mechanisms, tests of memory and learning count among the most performed behavioral experiments. Here, we will discuss available protocols for testing learning and memory using the example of the most prevalent animal species in research, the laboratory mouse. A wide range of protocols has been developed in mice to test, e.g., object recognition, spatial learning, procedural memory, sequential problem solving, operant- and fear conditioning, and social recognition. Those assays are carried out with individual subjects in apparatuses such as arenas and mazes, which allow for a high degree of standardization across laboratories and straightforward data interpretation but are not without caveats and limitations. In animal research, there is growing concern about the translatability of study results and animal welfare, leading to novel approaches beyond established protocols. Here, we present some of the more recent developments and more advanced concepts in learning and memory testing, such as multi-step sequential lockboxes, assays involving groups of animals, as well as home cage-based assays supported by automated tracking solutions; and weight their potential and limitations against those of established paradigms. Shifting the focus of learning tests from the classical experimental chamber to settings which are more natural for rodents comes with a new set of challenges for behavioral researchers, but also offers the opportunity to understand memory formation and retrieval in a more conclusive way than has been attainable with conventional test protocols. We predict and embrace an increase in studies relying on methods involving a higher degree of automatization, more naturalistic- and home cage-based experimental setting as well as more integrated learning tasks in the future. We are confident these trends are suited to alleviate the burden on animal subjects and improve study designs in memory research.

Opportunities to Improve Animal Welfare during Transport and Slaughter of Cattle and Pigs through Staff Training-Results of a Delphi Survey.

To improve animal welfare for cattle and pigs during transport and at slaughter, online training modules for all staff including employees in the lairage pen, the slaughter line as well as animal welfare officers are developed at Freie Universität Berlin, Germany. Before starting the development of these modules, an expert elicitation survey using a modified Delphi approach was performed to identify action points considered most relevant for animal welfare during transport and slaughter, and as having the potential for improvement through training. In total, 49 participating experts rated predetermined action points of each step in the transport and slaughter process in two survey rounds. The rating scale included numbers 0 (='not relevant', respectively 'no possibility of improvement') to 10 (='very relevant', respectively 'very high possibility of improvement'). None of the action points were rated with a median score of less than 5. Assessment of fitness for transport, unloading at the abattoir, handling at stunning and exsanguination were amongst the highest rated action points, and were therefore selected to develop online training modules. The Delphi approach was seen as a valuable method to include external expertise to select the most relevant action points for the development of online training modules.

A buprenorphine depot formulation provides effective sustained post-surgical analgesia for 72 h in mouse femoral fracture models.

Adequate pain management is essential for ethical and scientific reasons in animal experiments and should completely cover the period of expected pain without the need for frequent re-application. However, current depot formulations of Buprenorphine are only available in the USA and have limited duration of action. Recently, a new microparticulate Buprenorphine formulation (BUP-Depot) for sustained release has been developed as a potential future alternative to standard formulations available in Europe. Pharmacokinetics indicate a possible effectiveness for about 72 h. Here, we investigated whether the administration of the BUP-Depot ensures continuous and sufficient analgesia in two mouse fracture models (femoral osteotomy) and could, therefore, serve as a potent alternative to the application of Tramadol via the drinking water. Both protocols were examined for analgesic effectiveness, side effects on experimental readout, and effects on fracture healing outcomes in male and female C57BL/6N mice. The BUP-Depot provided effective analgesia for 72 h, comparable to the effectiveness of Tramadol in the drinking water. Fracture healing outcome was not different between analgesic regimes. The availability of a Buprenorphine depot formulation for rodents in Europe would be a beneficial addition for extended pain relief in mice, thereby increasing animal welfare.

Impact of Veterinary Herd Health Management on German Dairy Farms: Effect of Participation on Farm Performance.

German dairy farming has intensified markedly in recent years, and the demand for Veterinary Herd Health Management (VHHM) is rising. To protect farms from epidemics, ensure food safety, and prevent developing of antibiotic resistance, VHHM has been anchored in EU law since April 2021. Via an online survey, distributed by different farmers' organizations, dairy farmers were asked about the cooperation with their veterinarian. The aim was to evaluate farm performance as a function of participation in VHHM. From 216 analyzed questionnaires, 106 respondents participated in VHHM. Results showed that farmers who make use of VHHM and consult their veterinarian in decision-making frequently have the highest 305-day milk yield (305dMY), the lowest bulk tank somatic cell counts, and the lowest age at first calving (AFC). However, these farmers tended to have higher replacement rates and a higher mortality of cows in the period up to 60 days in milk (MORT60DIM). Furthermore, respondents who defined VHHM as "evaluation of herd data, strategic planning" had the highest 305dMY compared with those who defined VHHM through one of the different options given ("pregnancy checks and support in reproduction"/"problem solving"). In the multifactorial regression model, VHHM participating farms had a 660-kg higher 305dMY and 1 month less in AFC, compared with farms not participating in VHHM. However, within the VHHM participants, no association between VHHM practices and performance parameters was found. Further research is needed, to find out if tailored advice of the VHHM approach may show effect herein.

Keeping Stallions in Groups-Species-Appropriate or Relevant to Animal Welfare?

This literature review was aimed at analyzing whether stallion husbandry in groups is possible and desirable or poses risks. This was determined on the basis of different studies in order to be able to give practical recommendations from the viewpoint of animal welfare. Consequently, 50 different sources were analyzed, as well as observations of an experiment of the Swiss National Stud on the subject of change from single-stallion to group husbandry and its influence on animal welfare. The results revealed that stallion husbandry in groups is possible but still rarely practiced. It was found that 6% of stallions in 2003, more than 11% in 2012, and nearly 23% of the stallions in 2015 were kept in groups. Furthermore, studies showed that the still widespread individual husbandry of stallions has a negative impact on psyche and body health. Almost half of all stallions showed undesirable patterns of behavior, mostly stallions in individual housing. In addition, many of the latter stallions had problems with their respiratory, digestive, and musculoskeletal systems, which improved when the husbandry conditions of the horses were changed, with the exception of the problems with the digestive system. Conversion into group husbandry is possible, as revealed by an experiment by the Swiss National Stud with a socialization of active breeding stallions outside the breeding season. Therefore, the widespread fear of serious injuries for stallions housed in groups was refuted and the aggressive behavior of the stallions decreased rapidly. Success rates for group husbandry are influenced by the individual character of the stallion, previous experience of the stallion, changes in the group, qualification and management of the farm, and organization of the group housing and husbandry system. This enables species-appropriate husbandry in groups while also considering animal welfare without stress, disadvantages, and serious injuries for stallions.

Evaluating Horse Owner Expertise and Professional Use of Auxiliary Reins during Horse Riding.

Auxiliary reins are commonly used for the training of riders and horses as well as in daily training. They are often criticized when used incorrectly, as they will not help and can harm the horse by causing overwork, accidents, and injuries, which harm the horse in the long term. They also often conceal causal rider problems while trying to achieve quick success. The aim of this paper was to investigate, with an online horse-owner questionnaire, which and how often auxiliary reins were used and whether they were used appropriately. Only participants who were currently using auxiliary reins were selected. Consequently, 823 participants were questioned, of which 362 were currently using auxiliary reins at least every two weeks. Auxiliary reins were mainly used according to their discipline: the running side rein was the most popular when working from the ground and the sliding ring martingale was the most popular for ridden equestrian activities. Most of the test subjects only attached the auxiliary reins after the warm-up phase, but half of the participants did not change them during the entire training session. Most participants (75%) could at least identify what the correct head position of the horse should look like. However, there were still too many (50%) who adjusted their horse too tightly and did not change anything at that time despite the related breathing problems. The study found that most participants used the reins responsibly, but there is still a need for clarification and information relating to the functions of the different auxiliary reins among horse owners.

Breeding and Maintenance of Immunodeficient Mouse Lines under SPF Conditions-A Call for Individualized Severity Analyses and Approval Procedures.

In the EU, the breeding of genetically modified laboratory animals is, by definition, an animal experiment if the offspring may experience pain, suffering, or harm. In order to determine the actual burden of genetically modified mice, established methods are available. However, the breeding of immunodeficient mice is considered an experiment requiring a permit, even if no pain, suffering or harm is observed under scientifically required defined hygienic housing conditions, as determined by established methods of severity assessment. This seems contradictory and leads to uncertainty among scientists. With this commentary, we would like to shed light on this topic from different perspectives and propose a solution in terms of individualized severity assessment and approval procedures.

Benefits of Veterinary Herd Health Management on German Dairy Farms: Status Quo and Farmers' Perspective.

Veterinary Herd Health Management plays an important role in veterinary medicine on dairy farms and has also been mandatory at the European Union level since April 21, 2021. Despite the increasing importance of VHHM, little is known about the extent of utilization of VHHM by dairy farmers and their view on this type of collaboration. Therefore, this cross-sectional study aimed to determine the status quo of the currently practiced VHHM in Germany. For this purpose, an online survey was conducted among dairy farmers in November and December 2020. From 216 analyzed questionnaires, about half (n = 106) of the surveyed dairy farmers used VHHM at different scopes. However, regardless of the group, the term "veterinary herd health management" generally was given most relative importance by the participants as a veterinary service for herd fertility improvement, rather than the actual definition of a holistic approach. In contrast to this, the actual motivation of the VHHM participants, to take part in such a program was primarily based on the desire to safeguard animal health by employing preventive measures, that is, to avoid the occurrence of diseases via improved management and to improve farm performance (and profitability). Dairy farmers who opted for VHHM tended to manage larger higher yielding herds than those who did not. Additionally, the farmers in latter farms were more likely to make joint animal health decisions with their veterinarians. Using a latent class analysis, two groups of farmers among farms that were not currently using VHHM were identified, one of which expressed great interest in using VHHM while the other did not. Since the new legal basis makes the topic even more relevant than before, dairy farmers, animals, and veterinarians might benefit from the study to exploit hidden opportunities for VHHM collaboration.