Liubov Tupikina

Marc Santolini
email: marc.santolini@cri-paris.org

Boaz B Feldman

Integrating Developmental and Multi-Level Approaches in Somatic Practice: Insights from a Relational Embodiment Residency

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Background

The state of the nervous system is emerging as one of the most important factors when considering what influences behavior [START_REF] Mureriwa | Common Factors in Psychotherapy: The Autonomic Nervous System Final Common Pathway[END_REF]. Regulating the nervous system, which is when one contains threats states (fight, flight and freeze) and strengthen safe states (orientation and social engagement) has therefore been a topic of increasing interest. This emerged strongly in the West in the 1990's with Stephen Porges' Polyvagal theory. It was already established that the nervous system evolved from its primary response state of freeze, to more complex states of flight and then fight. Porges, as part of his polyvagal theory [START_REF] Porges | The polyvagal theory: Phylogenetic substrates of a social nervous system[END_REF], then found that the tenth cranial nerve called the vagus was not only activated during the freeze response, but also during states of what he called 'orientation social engagement'. These states are online when there is a sense of safety, of embeddedness and social connection. However, instead of being connected to dorsal structures of the nerve as it is during freeze states, these nervous system states of orientation and special engagement are wired to ventral structures of the vagus. This was a landmark finding in the field of somatic psychology because it opened a path to access and then unlock states of freeze which are "stuck" in the body (Van der Kolk, 2014), and heal trauma. Starting from a somatic framework based on the polyvagal theory, this article explores the ways in which nervous system regulation can be further understood, practiced and embedded within a developmental emphasis attuning from individual to increasingly large interpersonal scales of clinical practice.

Self-regulation

Attention-regulation capacity can be enhanced through individual experience, specifically focusing on qualities like mindfulness and self-compassion. This emphasis, particularly on interoceptive, visceral, and somatic phenomena, augments observer capabilities. Such enhancement can be conceptualized as an 'internal social engagement,' facilitating a heightened capacity to remain anchored and adeptly navigate emerging experiences. Following previous work which aims to integrate all dimensions of the inner experience by Lazarus in his Multimodal Therapy paradigm [START_REF] Lazarus | The multimodal assessment therapy approach[END_REF] and Levine in Somatic Experiencing [START_REF] Rappoport | Somatic Experiencing and Embodied Mentalization. Relational Psychoanalysis and Psychotherapy Integration: An Evolving Synergy[END_REF], we consider that the inner experience can be described according to channels encompassing Meaning, Orientation to the physical environment, Sensation, Affect, Image and Consciousness (MOSAIC) [START_REF] Feldman | Leading a group to neural wholeness[END_REF]. Introspective practices aimed at bringing awareness to all these channels support greater inner attunement, continuity to the flow of moment-to-moment emergence and increasing self-regulation. [START_REF] Lambert | Research summary on the therapeutic relationship and psychotherapy outcome[END_REF] Somatic techniques such as titration and pendulation [START_REF] Levine | Waking the Tiger: Healing Trauma: The Innate Capacity to Transform Overwhelming Experiences[END_REF] and positive psychology tools [START_REF] Garland | Positive psychological states in the arc from mindfulness to self-transcendence: Extensions of the Mindfulness-to-Meaning Theory and applications to addiction and chronic pain treatment[END_REF][START_REF] Rashid | Positive Psychotherapy: Workbook[END_REF] such as embodied resourcing and savoring of pleasure have been shown to help. However, a lot of empirical data over the last sixty years of clinical practice, summarized in the common factors approach [START_REF] Lambert | Research summary on the therapeutic relationship and psychotherapy outcome[END_REF][START_REF] Laska | Expanding the lens of evidence-based practice in psychotherapy: A common factors perspective[END_REF], show that a given therapeutic technique (such as somatic regulation and positive psychology), only account for around fifteen percent of the variance of successful therapy. Around thirty percent of the variance, twice as much as the technique, is explained by the quality of relationship between client and therapist (see figure 1). This co-regulatory wiring that evolved as a core function of our nervous system will now be explained.

Dyadic co-regulation

Consistent with other mammals, humans exhibit a neurobiological predisposition towards social safety due to evolutionary processes. This evolutionary trait bears significant relevance to clinical methodologies. In the 1950's Carl Rogers [START_REF] Rogers | Clientcentered theory[END_REF] revolutionized psychotherapy practice by advocating for humanistic person-centered principles. Rogers, rather than insight-centrism where the goal of therapy is to analyze and reach a particular type of understanding of one's own condition, emphasized that the posture of the therapist, one of unconditional positive regard, empathy and congruence was key to the healing and growth of clients. The common factors paradigm gives substantial credit to the importance of the "alliance" between client and therapist, as well as explicit agreement of the purpose of therapy (goals of treatment) and practices used to achieve these goals [START_REF] Messer | Let's face facts: Common factors are more potent than specific therapy ingredients[END_REF]. One of the key elements that stands out from the data is that the quality of alliance between the client and the therapist is twice as important as any of the specific therapeutic techniques used in treatment leading to successful therapy [START_REF] Lambert | Research summary on the therapeutic relationship and psychotherapy outcome[END_REF]. In order to develop this humanistic posture in a systematic manner through introspective practice, we reframe Rogers' humanistic posture with eight contemplative qualities: compassion, benign neglect, equanimity, friendliness, joy, gratitude, grief and assertiveness. In reference to the above theories, it is possible to link the therapist as a significant influence for regulation and resource availability during times of distress, offering a regulatory presence for clients. The client, through the process of being attuned to by the therapist, learns to be receptive to the way they attune to their MOSAIC unfolding. This is a skill which we term 'co-regulatory receptivity'. The client then learns to build an increasingly solid sense of self and develops greater ability to build their own perspective, technically termed in the developmental literature as perspective-taking [START_REF] Gehlbach | A New Perspective on Perspective Taking: A Multidimensional Approach to Conceptualizing an Aptitude[END_REF]. The social engagement system in Porges' Polyvagal theory (2001) gives a useful frame to understand this dynamic. Is it possible to further accentuate this relational container and increase our clients' access to bioenergetic resources?

The Social Baseline Theory [START_REF] Beckes | Social baseline theory: The role of social proximity in emotion and economy of action[END_REF] further propounds that when we feel safe in the company of others, neurobiologically we budget less bioenergetic resources to do the same tasks. For example, the quantity of glucose spent in the brain during moments of stress for the nervous system to regulate itself is reduced when we are with friends. Therefore, when one accesses states of freeze and trauma, being in the company of others will not only help to increase the proportion of neurobiological orientation and social engagement structures to come online, but it will be less effortful. This is significant because during freeze states, there are very few bioenergetic resources available, and little access to the body and feeling at all [START_REF] Price | Dissociation reduction in body therapy during sexual abuse recovery[END_REF]. Any additional sources of nutriment will have a big impact. So an important question then is, in the clinical context where freeze states are regularly experienced, how to increase the potential for social engagement wiring?

Collective co-regulation

One way to extend this regulatory potential is to go beyond the bounds of an individualistic approach. The intellectual tradition of individualism treats the individual person as the fundamental unit of analysis and reduces all things social to the motives and actions of individuals [START_REF] Campbell | How individual and face-to-face group selection undermine firm selection in organizational evolution[END_REF]. Most methods in clinical psychology are influenced by individualism and therefore treat the individual as the primary object of therapy/training. Multilevel selection theory [START_REF] Wilson | Rethinking the theoretical foundation of sociobiology[END_REF] offers an alternative to individualism in which individuals can be treated as a system in their own right, yet also offers a frame where individuals can become part of something larger than themselves that qualifies as an organism in its own right. The individual therapy format, through a strong alliance and trust between client and therapist, offers a dyadic merging opportunity, which afford minimal co-regulatory benefits. A group with six to eight members offers a collective merging opportunity to create a temporary social organism and thereby potentiates the number of network nodes upon which any individual can lean on to regulate themselves. In addition to co-regulatory benefits, group processes also enable the development of essential perspectival abilities such as perspective-seeking and perspective-coordination [START_REF] Fuhs | A latent growth analysis of hierarchical complexity and perspectival skills in adulthood[END_REF]. These skills are not only important to individuals in their growth as humans, but also form a solid basis upon which a group organism can emerge, since by seeking others' opinions and learning to include all members' views, respectively, group members learn to reflect upon one another and align in understanding and values. This results in group-as-a-whole embedded experiences and group-level self-organization [START_REF] Tschacher | Self-Organization in Social Groups[END_REF]. As safety and social engagement are progressively supported and strengthened in the group process, this form of practice multiplies the potential for each individual in the group of further affordances. Are there other ways to increase social embeddedness and potentiate co-regulatory mechanisms?

Another category of success factors described in the common factors literature is the extratherapeutic change, which are the factors changing in the clients' daily life outside of treatment. Data shows that the therapeutic process is successful to the extent that clients are able to transfer their experiences and learnings in therapy in their daily life, and vice-versa. It is striking to note that, according to the common factors research, it is these factors outside of the treatment context which most help patients get better (circa 40%), more so than the therapeutic techniques used (circa 15%) or even the therapeutic alliance (circa 30%) (see figure 1). One way to understand this finding is that while experiences and insight in the therapeutic setting are important, it is of even greater value to enable greater flow of integration between the therapeutic setting and the client's daily life. Put another way, it is less the content of therapy itself but more the transferential relationship between therapy and daily life which galvanizes most of our client's healing and wellbeing. The case study explored in the next section includes important pathways for such integration. Moreover, it is done in a community setting which offers the potential for community-as-a-whole embedded experiences. Relating back to multi-level selection theory, it is possible to further extend the scale of practice in order to include a wider community, national or even global levels. This would mean that relevant themes at these different scales could be addressed within therapeutic settings in order to support multi-level practices at the individual, collective and systemic dimensions. For example in the case of eco-anxiety, it would be possible to develop regulatory capacity at the individual and community levels through personal and group sessions to increase the sense of agency, to then enact and engage in one's daily life to support connect these lower two scales of embeddedness to the wider systemic scale.

In summary, it would seem that a multi-level framework could help bridge the gaps between the current state of research on effective therapy and practice. It offers an integrative perspective on internal-interoceptive practice, personal sessions as well as larger scales of group work and systemic practices. These four layers can be understood as delineating a spectrum of practices ranging from "sense to society".

Design and Implementation of a Relational Embodiment residency

Given the theoretical insights described in the previous section, we call for a renewal of methods and implementations by emphasizing multi-disciplinary and multi-level relational embodiment models of practice (Figure 2).

In March 2023, we implemented a prototype of such a practice during a "Relational Embodiment" residency, a two-week program with a series of practices. These were structured to maximize successful outcomes as described in the four different categories above: therapeutic technique, alliance, personal goal and expectation and the changes occurring outside of treatment. These practices can be delineated in four categories (Table 1 and Figure 3). In the following, we will provide a breakdown of each category, enriched by insights drawn from four post-residency participant interviews (Figure 4). These interviews provide valuable firsthand accounts, capturing the experiences of willing participants. While they do not constitute an exhaustive data collection method as discussed in the subsequent section, they are instrumental in enhancing our understanding, especially in the realm of somatic processes, by presenting the perspective of participants in their own words, alongside that of the authors. The residency began with a whole-group session, giving some orientation to the multi-dimensional and multi-level approach. There were regular moments of pausing and bringing awareness to the multi-dimensional present moment experience (somatic, affective, cognitive and relational), and some time into the different multi-level formations: dyads, small groups and whole-community exchanges. Each of these formations offer a number possibilities for experience and growth, categorized into (i) Self (ii) Dyad (iii) Group (iv) Community spaces and experiences.

Self practices

The residency offered daily opportunities for MOSAIC-level practices: there were morning meditations, regular dance and music sessions along with time for walks in nature and swimming in the river. In the words of a participant:

"I did morning meditation in the first week. I felt like this helped with grounding and creating a shared sense of rhythm with others."

These practices focus on developing wise awareness and a range of attention-regulation skills towards one's phenomenological experience and perceptions, particularly attention to one's senses in the environment (exteroception) and internal experience (interoception). The NeuroSystemics method divides this perceptual field into six channels, with the acronym MOSAIC: Meaning, Orientation, Sensation, Affect, Image and Consciousness. For example, in a morning meditation practice, one may bring attention to one's breath and body (sensation channel), feeling (affect channel) as well as a broader awareness of thoughts coming and going (meaning channel). During music, one tunes into the sound (orientation channel) and maybe some mental images emerge (image channel). Consistent with 5E models of cognition is intricately connected and interdependent with all the other channels. The realization of this interconnectedness is an essential stage of maturation for one to experience, and yet it is helpful to offer a scaffolded map helping discern and differentiate these channels to support the progressive integration into perceptual experience. Therefore, the practices at his level encouraged all individuals to choicefully find a SENSE-level practice which can help them strengthen attentional capacity to their present-moment experience in a resiliency-building way. As a result, participants were able to increase their abilities to pay attention to their experience, and the ways they are influenced by others and the space they are in. As one participants recounts:

"It was an experience to train a muscle which is: being present in the interactions with yourself and between yourself and the environments and with others."

Dyadic practices

Dyad level practices were offered through 1:1 session with facilitators and a "buddy-pairing system." Individuals receiving a 1:1 session will be able to form an alliance with their facilitator and regulate their nervous system through a sense of embeddedness in that trusted relationship. Facilitators were trained in somatics and systems approaches, helping individuals release tension and restore their capacity. In particular, all residency participants had a relational goal that they were working towards and facilitators could help them explore and untangle issues that arose during the residency. The buddy-pairing system, whereby participants had a daily discussion, offered another privileged space for sharing and exploring relational dynamics emerging between them and in the wider context of the residency activities. Both 1:1 sessions and the buddy system were designed to further strengthen participant's embeddedness in the residency by forming temporary dyadic organisms.

Group practices

The group practice involved participating in a small group (6-8 people) every other day. Two group facilitators held the space, bringing presence and awareness to the present moment experience, bringing light onto each of the channels, supporting the achievement participants' relational goals and strengthening an overall sense of embeddedness in the group (a group organisms/self). One core feature of these groups is that facilitators hold every experience, spoken, felt, embodied or interactive with a sense of unconditional basic regard and appreciation. As two participants note: Moreover, group spaces also encouraged the embodiment of a variety of attitudinal postures towards one's own experience or that of others, such as joy, friendliness, equanimity and compassion. Here is a sharing from a participant who discovered this way of relating to their experience through relational encounters:

"I
"By creating a compassion channel, with another person, or with a group, even though we've never experienced what they experienced, the fact that we can sit with them as they go through things, maybe it's going through a fight, right? We understand their point of view, but deeply we understand how they're feeling. It allows us to feel that same compassion for ourselves. And I really have the feeling that I did feel a lot of the pain, that for example, some members of my family suffered, I did feel very like strong, hurt, pain, but that was possible because I opened these doors through that person, and that was a gift, that was a gift to me."

There were also daily care duties that each participant fulfilled, such as cooking, cleaning and gardening. As people worked in small teams, these work periods also offered opportunities for group selves to emerge, coalescing and collaborating to achieve a collective goal. There was an encouragement for residency participants to use these daily care duties as exploration of their relational patterns, and ways to become more free relationally. For one participant who described challenges in being able to open up to and rely on others, they described their experience as "I really never felt like so many people had my back before."

There were also more informal opportunities to explore relational dynamics, such as meal times, walks and music playing, which was described as follows by one participant: Open space technology was used, whereby any participant could offer a group session on a particular theme, practice or discussion. The group would be led by them, providing bottom-up streams to build larger wholes in the residency space.

"
"Open spaces were not helpful when they had content similar to the program. Only helpful when it was physical exercise, music, art, painting."

"Many valuable practices were offered, I learned a lot. challenging was that there were maybe too many activities and too many things organised at the same time and in parallel."

These sessions were one of the more challenging areas of the residency. For example, the structured content group sessions and daily practices felt sufficient for some of the residents, which led to experiencing open sessions as overwhelming the program. Some difficult relational dynamics also occurred such as a small group of participants proposing most of the spaces, leading to frustrations by others who felt there was not enough space for them to contribute. There was also a sense that there weren't enough spaces to process some of these unfolding community dynamics.

"[The open space] was overwhelming… I felt frustrated to find time to meet one on one as everybody was busy with those open spaces . I felt them as distractions and fast food tools that can't be integrated anyway ; Capitalistic energy in my sense and fear of emptiness which burnt potential of just pausing and not learning, teachings all the time . FOMO was generated,

guilt and I felt it separated the group energy."

Community practices

Finally, there were periods where the entire community came together to explore a particular theme with an emphasis on process and present-moment experience, then breaking up into their respective small group formations, and then merging back into a wider community session. These intergroup process sessions offered a containing space to feel embeddedness in a wider whole (community self). This particular type of session offered experiential opportunities to sense into the different levels of self-building (individual, small-group and larger community selves). This next account describes the flow of social formations that were possible throughout the residency, giving a sense of the multi-level dynamics:

"There's a resiliency circle, and then there's a circle with everyone, but there's also so many smaller circles of all sizes really. Because we live together and we do some collective care of the house together, etc. In all these scales, you're presented with an opportunity to orient yourself. And so you have to recalibrate yourself in an energy of that particular group that you've not been doing the muscle with. And you're not building the flexibility with them. So each of these is an opportunity of testing in a way that muscle integrating what is that new environment you're into. And also nourishing yourself from other trajectories of the parallel trajectories. In other circles, each circle has their own personalities, their own typology and their own journey. And that could be a fear of missing out something that they've been through. So there's this kind of learning through the relation you have with these other circles. There's a setting where you're in a safe environment to be vulnerable and build flexibility. And there's that environment for the subgroup and for the very large group for the sharing."

Some community sessions were also provided with the aim of discussing a particular theme or issue that felt relevant to the community, with as much of a positive psychology attitude as possible. The social engagement system, our most refined way of experiencing ourselves, others and the world, is one of playfulness and joy. One participants described the residency in this way:

"At the end of these two weeks, I feel very playful, very playful, and at peace, and really, and beautiful, and this sense of peace and relief."

Overall, the reported experience relates to key elements including playfulness, joy, trust, and compassion, fostered through meaningful interactions. The structured environment allowed for emotional processing in the resiliency circles, leading to enhanced self-understanding.

Creative activities like music promoted deeper connections and shared joy, while the non-judgmental and open environment encouraged authenticity and valued individual needs. A mutual support system emerged, suggesting a strong sense of community. These factors synergistically contributed to personal growth and stronger interpersonal relationships.

Challenges & limitations

In the following, we highlight some limitations from the residency design that could be explored in next iterations.

The diversity of activities undertaken in the residency contributes significantly to a rich, immersive, and inclusive experience, accommodating various interests and learning styles. However, this broad approach presents a double-edged sword; while it enriches the learning environment, it risks overwhelming the participants due to overlapping schedules and potential dilution of focus. The challenge is to maintain diversity while ensuring a structured, balanced schedule that respects participants' needs for rest, personal space, and processing time. Some participants responded to the activities in this way:

"More time set aside [needed] for processing."

"WAY too many [open spaces]! It was awesome the first few days, then burnt me out completely. I would rather have more "integration time", and nothing before 5pm. Also, I would avoid any overlap with a shift."

"Having some morning or afternoon slots free (without open sessions) could allow more space for emergent interactions and help to mediate the feeling of overwhelm some people experienced."

The physical layout of the residency is another pivotal component, significantly influencing participants' experiences. While shared communal spaces foster a sense of community and collective engagement, the need for more private and quiet areas underlines a tension between collectivity and individuality. "There was no room for being in silence," one participant mentioned. Future residencies will need to carefully balance these needs, considering how the built environment can both support collective activities and respect individual needs for solitude and introspection.

Facilitators' roles are crucial to the smooth functioning and success of the residency. While their presence and guidance are necessary, a perceived hierarchical divide could potentially undermine the spirit of collective learning and shared experiences. This raises questions about the balance of power and engagement between facilitators and participants. Future designs need to carefully consider the degree and manner of facilitator involvement to nurture a more egalitarian and participatory environment. Some participants shared their feedback this way:

"I found it challenging to sense the strong disconnect of the facilitation team from the residents/participants by only being in the facilitation role in the [Resiliency Circle] as well as not really being part of the residency but rather coming and going in and out of the house." "I'm not sure as to whether separating the facilitation team from the residency fits the idea and possibilities of such a residency very well. I understand the difficulties in mixing up since you're coming from a clinical setting but it made things more rigid, it created more of a gap between facilitators and participants and I feel that shared residencies could go further than this."

One-on-one interactions are another aspect of the residency that, while valuable for personal connections and mutual learning, need more clear alignment with the residency's overall objectives. A more structured format might ensure consistency and effectiveness, but overly formalized interactions could risk stifling spontaneity and genuine connection. Future residencies must strike a delicate balance to maximize the value of these interactions without suppressing their inherent organic nature.

Mindfulness practices and group discussions promoted self-awareness, emotional release, and learning. Nevertheless, these sessions brought forward their unique challenges, particularly in managing group dynamics and providing sufficient post-session processing time. While these practices are invaluable, their implementation requires careful management to ensure they don't inadvertently induce stress or discomfort due to lack of time or space to process experiences.

In conclusion, each aspect of the residency presents its unique set of benefits and challenges. Recognizing these elements' complexity is critical in devising future residency formats that can optimize the benefits while thoughtfully mitigating potential drawbacks. This iterative refinement process is key to the continual improvement and success of relational embodiment residencies.

Research Perspectives

The therapy and residency model delineated in this study lays the groundwork for additional quantitative and qualitative research aimed at evaluating its effectiveness and refining its design. In the following sections, we propose a range of approaches to further this endeavor.

Research design

To elucidate the efficacy of therapeutic interventions, it is paramount to consider not only the immediate effects but also the longitudinal impact on an individual's mental health. This requires the implementation of a research design that encompasses a broad temporal scope, capturing the dynamics of therapeutic change and its enduring effects over time.

In this context, the pre-post design plays a crucial role. By obtaining baseline data prior to the therapeutic intervention (pre), and comparing it with the data gathered after the intervention (post), this design allows for a direct comparison of the individual's mental state and functioning before and after the therapy. This is particularly relevant to interventions such as the Relational Embodiment residency, where substantial changes in participants' mental states, relationships, and overall well-being are anticipated. The baseline data serves as an anchor point, providing a reference to compare and quantify the extent and direction of changes that occur due to the intervention. However, the evaluation of therapeutic effectiveness should not be limited to the immediate post-intervention phase. It is equally important to investigate the long-term impacts of therapeutic intervention. This could be achieved using a follow-up phase, with a recall period of 3-6 months after the residency. During this period, data could be collected to assess the maintenance of therapeutic gains and the potential emergence of any delayed effects. This follow-up data collection is crucial in understanding whether the benefits experienced by participants during the residency have been sustained, assimilated into their everyday lives, and have resulted in lasting improvements in their mental health and well-being.

Quantitative approaches for measurement

The utilization of non-verbal measurements in therapeutic outcome evaluation offers a pathway to assess the effectiveness of interventions. For example, technology such as smartwatches can capture physiological data in real-time [START_REF] Gloor | Aristotle Said "Happiness is a State of Activity"-Predicting Mood Through Body Sensing with Smartwatches[END_REF]. These devices, equipped with advanced sensors, are capable of measuring heart rate, skin conductance, and even the subtle changes in body temperature. Such physiological parameters can serve as proxies for different emotional states, stress levels, and overall mental well-being of the individuals . For instance, an increased heart rate and skin conductance could indicate heightened anxiety or stress. Similarly, variations in body temperature might reflect changes in emotional states. The continuous monitoring and analysis of these physiological parameters could provide valuable insights into an individual's internal state during the residency time and particularly within sessions, offering a quantitative understanding of their therapeutic journey that transcends the capabilities of traditional self-report measures.

Simultaneously, it is possible to employ sound analysis for verbal engagement assessment. This has been studied using sensors equipped with microphones in the context of group discussions to evaluate team performance [START_REF] Lederman | Rhythm: A Unified Measurement Platform for Human Organizations[END_REF]. One could similarly capture speech data during therapy sessions. The focus would not be on the content of the speech, but on the metadata: the tone, pitch, speed, and intensity of speech, and even the pauses between speech. Such data can be indicative of an individual's engagement level and emotional state during therapy. For instance, rapid speech might indicate anxiety, while low tone and intensity might be indicative of low stress and inner peace.

Systematic qualitative approaches for experience logging

Beyond objective data collection, the report of experiences through journaling represents a valuable method of data collection, providing an in-depth, subjective account of the individual's experience throughout the therapeutic journey. From a research perspective, the personal narratives captured through journal entries offer a wealth of qualitative data, providing insights into participants' internal processes, shifts in perspective, and changes in emotional states over time. These accounts can be used to supplement and contextualize quantitative data, offering a nuanced and richly detailed perspective of the therapeutic process. Importantly, these personal narratives also offer an individualized perspective on therapeutic progress, capturing the unique, subjective experience of each participant.

While journaling itself is an unstructured approach to reporting an experience, it is important to provide a container through which the ensemble of reports from an individual can be analyzed to derive causal relationships that underpin therapeutic progress. Digital platforms can facilitate this process by providing user-friendly tools for activity logging and ecological moment assessment using textual and verbal integration. For example, recent studies in health and psychiatry [START_REF] Klein | Remote Digital Psychiatry: MindLogger for Mobile Mental Health Assessment and Therapy[END_REF] have leveraged digital mobile applications that use active methods of experience sampling, including explicit self-reports that may range from occasional and detailed survey instruments to more frequent, brief and in-the-moment questionnaires that are referred to as "ecological momentary assessment" (EMA). EMA offers a number of major benefits over traditional survey instruments including the reduction of retrospective bias, realtime tracking of dynamic processes, simultaneous integration of multi-level data, characterization of context-specific relationships, inclusion of interactive feedback, and enhanced generalizability of results.

Measuring changes in the relational structure

Beyond individual-centric data, the efficacy of the relational embodiment approach could be assessed through the examination of changes in the valence and strength of relationships using social network data collection [START_REF] Tackx | Quantified Us: A group-in-the-loop approach to team network reconstruction[END_REF] and structural analysis [START_REF] Grabowicz | Distinguishing topical and social groups based on common identity and bond theory[END_REF][START_REF] Masselot | Collaboration and Performance of Citizen Science Projects Addressing the Sustainable Development Goals[END_REF]. This perspective brings a layer of relational analysis, extending the scope of data from individual experiences to collective dynamics. In the context of group therapy, the interactions and relationships between participants become an essential part of the therapeutic process. By analyzing social network data, researchers could gain insights into how these relationships evolve over the course of therapy, and how changes in relational dynamics might correlate with therapeutic outcomes.

In addition to understanding the valence of relationships, social network analysis could illuminate patterns of interaction and influence within the group. For instance, the emergence of supportive subgroups, shifts in communication patterns, or changes in the centrality of participants within the network could all be indicative of progress in therapy. Furthermore, the combination of social network data with individual-level data from journaling and EMA could provide a more holistic and nuanced understanding of the therapeutic process. For example, patterns of change in relational dynamics could be cross-referenced with changes in individual emotional states or perspectives as captured in journal entries and EMA responses using Natural Language Processing techniques [START_REF] Aiello | Nature of Social Structures[END_REF]. This multimodal approach to data collection and analysis could provide a robust method for assessing the efficacy of group therapeutic treatments, while accounting for the complexity and interconnectedness of the therapeutic process.

Incorporating these strategies within digital platforms could provide a cohesive system for collecting, managing, and analyzing this rich dataset. Integrating these methods of relational data collection and analysis [START_REF] Tackx | Quantified Us: A group-in-the-loop approach to team network reconstruction[END_REF] with existing tools for activity logging and ecological momentary assessment [START_REF] Klein | Remote Digital Psychiatry: MindLogger for Mobile Mental Health Assessment and Therapy[END_REF] could transform these platforms into powerful tools for researching and evaluating therapeutic interventions in group settings.

Journaling as an integration practice

By documenting their experiences in a systematic manner, individuals are encouraged to reflect on their activities, interactions, and personal transformations. This can reveal patterns and connections that would otherwise remain obscure, elucidating the causal pathways by which certain practices lead to therapeutic outcomes and providing emotional discharge. For instance, an individual might notice that their practice of daily meditation leads to increased calm and focus, which then enhances their ability to engage with their buddy in a more present and empathetic manner. This improved buddy interaction may then contribute to a more cohesive and supportive group dynamic, which in turn could foster a more inclusive and harmonious community atmosphere. Observing and understanding these chains of causality can help individuals to appreciate the value of their practices and to make more informed decisions about their therapeutic journey. Journaling can also have buffer effects for stress, as was shown in nurses [START_REF] Dimitroff | Change your life through journaling-The benefits of journaling for registered nurses[END_REF]. The collection of data points across several participants can then be leveraged to capture these insights quantitatively, in an approach similar to the Quantified Self movement for health-related contexts promoted by Open Humans [START_REF] Greshake Tzovaras | Using an Individual-Centered Approach to Gain Insights From Wearable Data in the Quantified Flu Platform: Netnography Study[END_REF][START_REF] Greshake Tzovaras | Open Humans: A platform for participant-centered research and personal data exploration[END_REF].

Finally, beyond the obtention of valuable research data, journaling is a therapeutic tool in itself, fostering self-reflection, self-awareness, and ultimately aiding the integration of therapeutic experiences into one's daily life, which is a critical element of therapeutic change. By encouraging participants to reflect on their experiences, thoughts, and feelings, journaling can help individuals to make sense of their experiences and to weave them into their broader life narrative. This process of introspection and self-reflection is a key component of many therapeutic models, promoting self-awareness, insight, and personal growth. The integration practice of journaling is notably used in the context of psychedelic treatments. Following such treatments, participants are often asked to document their experiences and insights, providing a structured format for the process of integration. The act of writing helps to consolidate and process the often intense and transformative experiences encountered during psychedelic therapy. These integration reports serve a similar function to journaling in the context of the residency, providing a method for individuals to reflect on, understand, and integrate their experiences.

Towards a "contemplative action research"

Overall, these methods pave the way for an approach that stands between participatory action research and contemplative science, benefiting both data collection processes and the deepening of individual therapeutic experiences. Participatory action research represents a methodological approach that values the active involvement of individuals in the research process [START_REF] Heron | Co-operative inquiry: Research into the human condition[END_REF]. This research paradigm treats participants not as passive subjects, but as co-researchers, empowered to contribute to the design, execution, and interpretation of research that directly impacts their lives. This approach can enhance the relevance and applicability of research findings, as the collected data is grounded in lived experiences and the interpretations are co-created with those who are most intimately familiar with the context. In the case of therapeutic interventions, this implies that participants can contribute valuable insights into the effectiveness and appropriateness of the practices in which they are engaged. On the other hand, contemplative citizen science offers a novel fusion of contemplative practices with citizen science methodologies, thereby integrating subjective experience and objective data collection. In this approach, participants' personal contemplative practices (e.g., meditation, reflective journaling) become a source of rich data, documenting the nuances of their internal experiences. Meanwhile, the methods of citizen science provide a rigorous and structured framework for collecting, managing, and analyzing this data. The result is a form of research that honors and harnesses the richness of inner experience while maintaining the rigor and reproducibility of scientific inquiry.

When integrated within the therapeutic process, these research perspectives can not only contribute to the generation of robust and meaningful data but also serve to deepen the participants' personal experiences. Participatory action research fosters a sense of agency and ownership, enhancing engagement and motivation, while contemplative science encourages introspection and awareness, furthering personal growth and integration. Thus, the research process itself becomes a therapeutic tool, contributing to the transformative potential of the therapy. In addition, as participants engage in self-research and share their experiences and findings, communities of practice can emerge. These communities serve as a support network, promoting shared learning and mutual support. They can also contribute to a sense of belonging, enhancing motivation and engagement in the therapeutic process.

In addition, these communities represent a rich source of diverse experiences and perspectives, enriching the collective knowledge and fostering innovative insights. By bridging the gap between personal experiences and scientific research, these approaches offer a promising avenue for advancing our understanding and practice of therapy.

Conclusion

In this study, we propose a multi-level, multi-dimensional therapeutic model to address the varied dimensions of individual well-being. Informed by Polyvagal theory, the model recognizes the critical role of the vagus nerve in manifesting trauma states in the body and the therapeutic potential of enhancing attention-regulation through mindfulness and self-compassion. The therapeutic model not only focuses on the client-therapist alliance, which accounts for approximately thirty percent of the variance in therapy outcomes but also accentuates the significance of interpersonal relationships to increase the ability of patients to transfer their therapeutic experiences and learnings to daily life. We propose an extension of the therapeutic scope, ranging from individual sessions to larger group work and systemic practices, thereby extending the scope of therapy to include community, national, and even global levels, fostering a more comprehensive range of practices from individual to societal scales.

The "Relational Embodiment" residency program served as an effective instantiation of our proposed model. The program emphasizes the importance of developing a healthy relationship with different objects of awareness, following Kegan's empirically-based constructive-development theory of personality. This program incorporates various practices across four levels -MOSAIC, Dyadic, Group, and Community -fostering personal growth and the formation of deeper interpersonal relationships. MOSAIC-level practices include meditation, dance, music, relaxation, walking, and art creation to strengthen attentional capacity and resiliency. Dyadic practices involve one-on-one therapy sessions and peer discussions to explore relational goals, providing opportunities to form deep connections and express experiences. Group practices focus on small professionally facilitated group sessions and community activities. These allow participants to experience and explore present moment experiences in relation to others, increasing their awareness and understanding of their own and others' experiences. Community practices involve larger group sessions and shared daily tasks like cooking, cleaning, and gardening to build a sense of unity and shared responsibility. We believe the program illustrates the potential for integrating a range of experiential practices within a therapeutic framework, presenting promising avenues for future therapeutic interventions.

Finally, we discussed a hybrid research model that combines quantitative and qualitative methods for evaluating and refining the residency program. We identified a pre-post design as crucial for capturing longitudinal impacts on mental health. Quantitative measurements using technology like smartwatches and sound analysis tools can offer insights into the individual's physiological and emotional states. Simultaneously, qualitative methods, particularly journaling, could afford a comprehensive picture of the individual's experience, aiding in self-reflection and therapeutic integration. The incorporation of social network data collection can further supplement this approach, providing a holistic perspective on relational dynamics throughout therapy. Lastly, we proposed a "contemplative action research" approach to engage participants actively in the research process. This not only ensures the generation of robust and meaningful data but also allows the research process to become a therapeutic tool in itself, fostering a sense of agency, introspection, and shared learning within the community. Therefore, by integrating a multi-dimensional therapeutic model, comprehensive research design, and active participant engagement, we believe we are moving closer towards a more nuanced and effective therapeutic practice that addresses individual well-being in its full complexity. Future studies can further explore and refine these methods and practices, contributing to the evolution and efficacy of therapeutic interventions.

Figure 1 .

 1 Figure 1. Percent of improvement in psychotherapy patients as a function of therapeutic factors[START_REF] Lambert | Research summary on the therapeutic relationship and psychotherapy outcome[END_REF]

Figure 2 .

 2 Figure 2. Schematics of the proposed multi-level developmental framework

Figure 3 .

 3 Figure 3. Overview of the various scales and frequencies of the practices. In the top networks, nodes are individuals and possible social interactions are depicted.

Figure 4

 4 Figure 4. a. Network representation of the interactions between participants (blue) and facilitators (yellow). The links in the network represent the involvement in a shared practice (Buddy, Resiliency Circle, or Empowerment Forum) between two individuals. Thicker edges indicate more shared practices, with low opacity thin edges showing the complete network generated by the empowerment forums. We observe the three RC groups, as well as inter-group connections representing open forums (thin edges) and buddy relationships (thick edges). b. Word cloud representing the most frequently used words across interviewed participants to describe the practices and their impact.

Table 1 .

 1 Overview

	Level	Practices	Description	Intended developmental Outcomes Frequenc
					y
	Self	Meditation,	Introspective attunement &	• Embodying self-regulatory	Daily
		dance, music,	awareness practices	attentional postures of
		relaxation,	towards one's present	compassion, equanimity, joy
		walking &	moment experience of	and assertiveness in relation to
		art-creation	MOSAIC channels: Meaning,	one's own experience and
			Orientation, Sensation,	• Discernment in MOSAIC
			Affect, Image &	channels as they emerge
			Consciousness
	Dyadi	1:1 therapy	Professionally facilitated	• Co-regulatory receptivity: enjoy	Voluntary
	c	sessions	sessions with a	being supported through the
			experiencing and exploring what emerges in the present moment experience internally	facilitator's attentional postures of compassion, equanimity, joy and assertiveness in relation to one's own experience
				• Perspective-taking skills
		Buddy	Peer sessions to explore	• Embodying self-regulatory	Daily
		discussions	relational goals in the	attentional postures of
			residency	compassion, equanimity, joy

of practices offered during the two-week residency program

  learned, I felt that I learned a lot about the power of holding and welcoming whatever is manifesting and welcoming all parts of ourselves

but welcoming and including each part of that circle and that in a way that circle isn't complete if one part is missing. So that there is that sense that each element of the circle was essential for it to function and journey together towards more freeing ways of relating with each other and therefore also of relating to ourselves." "I felt like authenticity was really valued. And there was, you know, not like a judgment experience. It was really open and you could be vulnerable. Yeah. You know, it's funny. I think what happened was that people really said things that were hard or disagreed. It wasn't that everything's like, oh, everyone's getting along. It's so nice. Like somebody said something and then someone reacted and that was welcome. But it wasn't welcomed in a harshness. It was welcomed like, okay, thank you for sharing that. Tell us what your experience is. And then the other person can hear what that is. And, things really got resolved in a peaceful way. There was a room for everything."

  As part of being here, I have never had as much fun with music. I've always loved music. But here we sort of explored it in a very unstructured way. And it was play. It was playtime. We had four or five people who, you know, we would just find things around and start making sounds with them.

And then just build on that and build on that and build to these like crescendo of emotion and fun and connection together. And there was always just this like joy, immense joy to just play together. So I think because we made music together, which is such a creative process, we also felt each other. And then we, when you make music with someone, you also learn about them. You know, it's very much sharing and giving take and building off each other. So it's a lot of synergy. So then if you're sitting with someone eating and that you shared that, you're just closer. There's a connection. Okay, so there's a kind of intimacy created through the playfulness. And feeling safe with the person, feeling like, because when you make music, there's a vulnerability. You're being creative. You're showing yourself."


M Ithurbide
email: marie.ithurbide@inrae.fr

C Huau

I Palhière

T Fassier

N C Friggens

R Rupp

Selection on functional longevity in a commercial population of dairy goats translates into significant differences in longevity in a common farm environment

Keywords: functional longevity, hyperselection, survival analysis, dairy goat

INTRODUCTION

There is increasing interest in animal robustness as a trait of importance in the future design of livestock systems, and genetic selection strategies to select for it are increasingly being sought. Food security in a world affected by climate change means that animals will be exposed to, and have to cope with, harsher and more variable environments. More specifically, small ruminants have shown great ability to thrive in very harsh environments (i.e., they can display a high level of robustness). In the context of robustness, it is useful to consider the environment as having 2 components [START_REF] Friggens | Review: Deciphering animal robustness. A synthesis to facilitate its use in livestock breeding and management[END_REF]. The first is general "harshness" of the environment, requiring long-term adaptation mechanisms as a first aspect of robustness. The second component of the environment relates to the frequency and intensity of environmental perturbations. Animals respond to these shorter-term perturbations by a dynamic pattern of response and recovery that is usually referred to as an animal resilience mechanism [START_REF] Colditz | Resilience in farm animals: Biology, management, breeding and implications for animal welfare[END_REF]. The animal's resilience can be seen as the most determinant part of robustness in a wellcontrolled farming environment (i.e., when harshness of the environment is low).

It is relevant to see functional longevity as strongly correlated with resilience because it results from the accumulated consequences of ability to cope with and recover from all the challenges faced throughout an animal's lifetime. Thus, it can be assumed that animals with poor resilience have shorter longevity. Longevity corresponds to (1) true longevity that includes all culling reasons and (2) functional longevity (all culling reasons, except productivity; [START_REF] Sasaki | Estimation of genetic parameters for longevity traits in dairy cattle: A review with focus on the characteristics of analytical models[END_REF]. It has recently been proposed that functional longevity may be a good proxy for resilience [START_REF] Rostellato | Influence of production, reproduction, morphology, and health traits on true and functional longevity in French Holstein cows[END_REF]. There is evidence that functional longevity has a genetic control and can be transmitted to progeny, as heritability estimates were around 0.10 (ranging from 0.1-0.29) in cattle [START_REF] Sasaki | Estimation of genetic parameters for longevity traits in dairy cattle: A review with focus on the characteristics of analytical models[END_REF] and in the range of 0.10 to 0.14 in goats [START_REF] Castañeda-Bustos | Linear and nonlinear genetic relationships between type traits and productive life in US dairy goats[END_REF][START_REF] Palhière | Functional longevity is heritable and controlled by a major gene in French dairy goats[END_REF]. Accordingly, functional longevity has already been included in breeding programs of cattle [START_REF] Miglior | Selection indices in Holstein cattle of various countries[END_REF][START_REF] Miglior | A 100-Year Review: Identification and genetic selection of economically important traits in dairy cattle[END_REF][START_REF] Tsuruta | Changing definition of productive life in US Holsteins: Effect on genetic correlations[END_REF] as a proxy for improving animal resilience and overall lifetime efficiency together with improving productivity. However, functional longevity is a complex trait, and the underlying mechanisms that are selected remain largely unknown. Furthermore, as genetic evaluation is made from commercial population data (i.e., numerous farms with different environments), there is a need to check the validity of the genetic response in the same farm environment.

Accordingly, the aims of this study were to (1) validate the creation of hyperselected lines of goats for functional longevity, (2) compare the longevity of the 2 lines raised in the same environment, and (3) explore factors that contribute to the difference of longevity to better understand the resilience mechanisms involved.

MATERIALS AND METHODS

The experiment was carried out in agreement with French National Regulations for the humane care and use of animals for research purposes. Animals were bred at the experimental INRAE farm (La Sapinière, Osmoy, France, experiental approval: C18-174-01). The experimental approval was APAFIS#8613-2017012013585646 V4.

Animals

Following the method developed by [START_REF] Palhière | Functional longevity is heritable and controlled by a major gene in French dairy goats[END_REF], a genetic evaluation for functional longevity of 8,787 Alpine AI bucks was carried out. Briefly, length of productive life was computed for 84,454 Alpine goats as the time interval (in days) between first kidding (first milk recording) and the last milk recording registered in the national performance-recording database. Estimated breeding values for length of functional life were then estimated for AI bucks using BLUP based on phenotypic information, pedigree information, and variance component estimates. Sires of the 2 lines were also required to show similar and favorable EBV for milk production traits to avoid confounding effects from an indirect response to selection for production traits. In 2020, the EBV of the bucks used were +85.1 d of functional life for the bucks of high longevity (high_LGV) lines and -108.7 d for the bucks of low longevity (low_LGV) lines (Table 1). From 2017 and until 2021, we selected 35 AI bucks in total as follows: the 16 bucks who had the highest EBV among the whole AI bucks population founded the high_LGV line and the 19 bucks who had the lowest EBV founded the low_LGV line (Table 1).

The selection was mainly made on the males; the very strong selection that was made on the buck (the most extreme EBV of the national database) was relevant to create a model to produce the most divergent animals possible using functional longevity-based selection (high selection pressure on males: 36 out of 8,787 bucks with breeding values). In the later years of the a-c Letters correspond to significant differences within a row (P < 0.001).

study, some animals were daughters of high_LGV or low_LGV mothers (of the 440 females used, 262, 144, 41, and 3 were from generation 1, 2, 3, and 4, respectively). We produced goats belonging to the high_LGV and low_LGV lines at the experimental INRAE farm (La Sapinière, Osmoy, France). Numbers of goats bred per year are shown in Table 2. All goats were managed identically in the same facility. The farm staff did not know which line the goats belonged to. They were reared indoors all year round, and inseminated at about 7 mo of age. Reproduction was seasonal, and kidding ranged from January until early February. Milking occurred twice a day with a DeLaval milking machine (DeLaval France) in a Rotolactor parlor (Eurl Gabard Systeme) from February to October. Goats were then dried off for 3 mo. The ration was based on Lucerne hay and complemented with concentrates dispensed in the milking parlor and in collective troughs. No culling for low production reasons took place during lactation or at drying off during this period (up to the end of third lactation). At the age of 2 mo, all goats were treated against coccidiosis (Toltrazuril, Baycox) and were vaccinated against Q fever at the age of 4 mo (Coxevac). The kids that died before 24 h of life were not included in the analysis (they corresponded to abortions).

Survival Length

Throughout the study, for a cleaner assessment of functional longevity, goats were not culled for performance reasons, which included not being culled for failure to conceive. This resulted in a small number of goats being kept for years without giving birth. However, this does not correspond to what is done in commercial farms. Therefore, it was decided to adjust the culling age for goats that were not pregnant during 2 successive years (1 yr of reproductive failure was tolerated). In this situation, the date of the last negative pregnancy determination (by ultrasound) was set as the culling date. This equated to culling ages of 680 or 1,080 d, depending on the year of the first nonbirth. Consequently, we modified 15 dates of culling for 2 yr of successive reproductive failure.

Data Used to Decipher Survival

Each reason for culling was indicated by the farm staff. For processing, these data were grouped into the following 6 classes of culling reason: birth-associated, infection, accident, metabolic, skinny, and other. The passive immune transfer from the goat to the kid can be evaluated measuring serum IgG concentration at birth [START_REF] Weaver | Passive transfer of colostral immunoglobulins in calves[END_REF]. It was done by a radial immunodiffusion technique between 1 and 14 d of age. Logarithmic transformation was applied to values before statistical analysis to normalize the distribution of the data. The date of each kidding was recorded, as well as any difficulties during kidding, the number of kids, and the weight of the litter. All health treatments were recorded in the same way and then grouped into the following 5 groups: infection, accident, metabolic, mechanical, and other.

Milk yield, milk fat content, milk protein content, and SCC were measured every 3 wk in first lactation, as part of the official milk records for the herd. The lactation somatic cell score (LSCS) was computed from the monthly test-day SCC in a 250-DIM period as described by [START_REF] Rupp | Divergent selection on milk somatic cell count in goats improves udder health and milk quality with no effect on nematode resistance[END_REF]. Briefly, the test-day SCC were transformed to SCS by logarithmic transformation to achieve a normal distribution. The LSCS was then computed as the weighted arithmetic mean of the test-day SCS, adjusted for DIM. Total milk was calculated with the Fleishmann method using test-day records of each in 90 (MY90) or 250 DIM (MY250) lactation periods [START_REF] Ruiz | Comparison of models for describing the lactation curve of Latxa sheep and an analysis of factors affecting milk yield[END_REF]. The milk fat-to-protein ratio was calculated for the first test day in lactation (between 1 and 45 DIM).

Chest size and height at the withers were measured every 2 mo during the first year and from then on 1 to 4 times per year. Goats were weighed every single month from birth to the age of 1 yr and from 2 to 5 times a year thereafter. The BW data were processed for inclusion in the survival analysis, as follows.

Integration of Weight Data During the First Year of Life

We used the functional data analysis smoothing method described by [START_REF] Ramsay | Functional Data Analysis[END_REF]. The application of this method to the BW data made it possible to estimate a corrected weight of individuals for every month from birth to 1 yr old as well as the first derivative. We used B-spline basis functions, which can construct piece-wise polynomial functions joined at the knots. The roughness penalty is adjusted by the scalar λ, (as λ increases, the penalty term becomes more decisive, and thus the second derivative converges to a straight line). The B-spline smoothing was run over 6,747 BW records for the 364 goats that were weighed at least 5 times (from 5-27 times). The age of the 75 goats for which less than 5 weight measures were recorded ranged from 1 to 30 d old.

To deal with the inevitable correlation between BW and age (thus BW and survival), a weight deviation (WD) was calculated, allowing the weight of an individual to be compared with that of other individuals of the same age as follows:

WDij Wij W j Wj = - ( ) ( ) mean SD ,
where WDij is the WD value of animal i for month of age j; Wij is the estimate of the weight after smoothing of individual i for month j. Mean(Wj) and SD(Wj) are the mean value and the standard deviation of the estimated weights in month of age j.

To include the weight record of kids who died early in the survival analysis, as all goats were weighed at birth, we decided to use the raw weight value (not estimated by B-spline analysis) for the first month WD calculation. A single value per animal was also calculated to summarize the average WD during the first year of age as follows:

mean_WDi = mean(WDij),
where WDij are all weight deviations of the ith animal for months ranging from j = 1 to 12. The same method was applied on the first derivative of the weight curves to calculate the growth rate deviation and the mean speed of growth deviation as follows: dWDij and mean_ dWDi. The effect of mean_WDi and mean_dWDi were tested in the survival analysis after 1 yr of age to check if the growth during the first year of life had an effect on later survival.

Statistical Tests

All statistical analysis were done in the R statistical environment (https: / / www .r -project .org/ ). We ran linear regression using the lm and glm to compare between the 2 lines as follows: weight at birth, mean WD (meanWD), mean growth rate deviation (mean_dWD), log-transformed serum immunoglobulin concentration, and first lactation MY90, MY250, milk fat-to-protein ratio, and LSCS. Fixed effects were as follows: line and year in all models, as well as number of kids for weight at birth and age at first kidding for MY90, MY250, milk fat-to-protein ratio, and LSCS.

Mixed models with an animal random effect were run for repeated data as follows: weight, chest size, height, number of treatments per year, kidding per adult year (logistic regression), and number of kids per kidding. We used the lme4 package in R [START_REF] Bates | Fitting linear mixed-effects models using Lme4[END_REF].

Only months when at least 20 goats were recorded were included in the analysis for weight and body morphology. We used raw data (no Spline transformed) to compare weights after the first year of life. We included the fixed effect of gestation during the 3 last months before kidding (0 vs. 1) for weight analysis. Supplementary analyses were run where line effect was nested into month for weight and body morphology analysis.

Survival Analysis

The R package 'survival' was used for the survival analysis [START_REF] Zhang | Time-varying covariates and coefficients in Cox regression models[END_REF]. Survival analysis was performed using a Cox model [START_REF] Cox | Regression models and life-tables[END_REF] as follows:

log l og , h t x h t x | ' ( ) ( )= ( ) ( )+ 0 β
where h(t) is the expected hazard at time t, h0(t) is the baseline hazard, and β is the coefficient associated with the covariate x′. The model included both fixed effects (i.e., those that were the same through all the animal's life including line, year of birth) and time-dependent covariates using the monthly records for data that changed with time [START_REF] Zhang | Time-varying covariates and coefficients in Cox regression models[END_REF]. The physiological status of the goats (kidding or not), their weight, and any treatments received could change every month. Before 1 yr old, the weight variable affecting survival at month j was assumed to be the weight deviation value at month j -1 (WDj -1). After the first year, the weight variable used was meanWD fitted as a fixed effect. The effect of the occurrence of a treatment or a kidding (both coded as 0 or 1) was evaluated over 3 mo after the event recording (i.e., the dummy variables were set to 1 if the event had occurred during the last 3 mo).

The proportional hazards hypothesis of the Cox's model [which is that the risk ratio (β) is assumed to be constant regardless of the age considered] was tested by visual inspection of the standardized Schoenfel residuals [START_REF] Zhang | Time-varying covariates and coefficients in Cox regression models[END_REF]. When the proportional hazards hypothesis was not found to hold, the hazard ratio was calculated separately over different time intervals using a stratification method (β is then considered constant within the different time intervals but differs between time intervals).

We selected the co-variables that remained in the survival model with a downward stepwise method from the maximum model, using a P-value threshold of 0.05. Because of the number of goats included in the survival analysis, interactions were not included in the model.

RESULTS

Proportion of Culling, Health Treatments, and Reproductive Performances

No significant differences were found between lines in the causes of culling. Cullings related to infections and accidents represented the 2 largest groups (54 goats each) followed by the birth-related group (48 goats). The birth group consisted of all deaths registered before 5 d and is the largest group of culling reasons that occurred in the first year of life (Figure 1). This represented 27% of culling in the first year on average (31% and 23% in the high_LGV and low_LGV lines, respectively). After the first year of life, infections represented the main cause of culling (11.6% and 20.3% in the high_LGV and low_LGV lines, respectively). Despite the small number of cullings in each group, low_LGV goats were more numerous in the infection group as follows: 7% of high_LGV goats (16/228) and 12.7% of low_LGV goats (27/212).

There was no significant line effect on the number of treatments received per year (Table 3). Between 2017 and 2021, 344 treatments were given as follows: 171 (49% of goats) to high_LGV goats and 173 (51% of goats) to low_LGV. Age at treatment ranged from 8 to 1,576 d. Infections represented 269 (78.2%) of these treatments (Figure 2).

No line effect on number of kiddings was found (P = 0.7). On average, 67.8% of goats had a kidding per adult year (Table 3). There were 424 kiddings, of which 199 were low_LGV, and 225 were high_LGV. Similarly, the mean number of kids per kidding was 1.45 (min = 1, med = 1, max = 5) and was the same for the 2 lines (Table 3). The majority of kiddings were recorded as "normal" and 49 were "difficult" (12.8% of low_LGV kiddings and 12.7% of high_LGV kiddings). There were 247 goats with at least 1 kidding recorded.

The median number of body morphology records per goats was 6. Mixed models were applied to height and chest size data over the whole life of goats. A line effect was found for chest size (P = 0.03), with high_LGV goats having a greater chest size than low_LGV goats (83.7 cm vs 83.0 cm).

The weight at birth was similar for low_LGV and high_LGV (mean = 3.94 kg, min = 1.6, max = 5.9, n = 440), as well as mean weight deviation (mean_WD) and mean speed of growth deviation (mean_dWD; Table 3). No line effect was found. However, when the line effect was nested into the month effect, high_LGV goat were significantly heavier than low_LGV line between 12 and 16 mo (F test; P < 0.05), with a difference of 1.5 kg between lines at 13 mo of age (t-test; P = 0.003). Differences between lines were also significant at 24, 25, and 35 mo of age (Table 4). Smoothed weight curves of the 341 goats who had at least 5 weight measurements are shown in Figure 3.

Survival Analysis

There were 440 goats included in our study; 246 of them had been culled at the time of analysis. More low_LGV goats had been culled than high_LGV goats (62.4% and 49.5%, respectively; Table 3). Out of 440 goats, the 194 (44.1%) animals that did not exit the flock before the end of the study were considered as censored. The Kaplan-Meier curves of the 2 lines are displayed in Figure 4. It shows a steep decline in the first few days after birth of the kids because 16.8% (74/440) of the goats died within the first month. The survival of low_LGV goats seemed slightly better during the first year, yet not significant, before curves crossed around 450 d of age.

The Schoenfeld residual analysis showed evidence of violation of proportional hazards assumption for line effect (P = 0.01). From the visual inspection of the residual plot (Figure 5), we can see that the residuals for the high_LGV line relative to the low_LGV line (shown as the reference line) decrease over time. The line effect was not significant during the first year, whereas the high_LGV line tended to be associated with a lower risk of being culled after 600 d of life, and more so after the second year. The Schoenfeld residual analysis showed no evidence of other factors that did not fit with the proportional hazards assumption, except for treatments (P = 0.02). However, no inversion of the line and treatment effect was observed. Thus, we decided not to stratify the line and treatments analysis over the different stages of life of the goats as it would not change the interpretation of the results.

The results of the multivariate Cox regression, including all significant covariates, are reported in Table 5. Significant effects (P < 0.05) were found for the fol-lowing: line, speed of growth deviation (dWD) before 13 mo, year of birth, health treatments, and high IgG concentration. The effects of birth weight as a fixed effect, monthly WD during the first year, latent effect of mean WD during the first year over the survival after the first year, WD after the first year, normal or difficult kidding (versus no kidding), and number of kids after a kidding were tested but found not to be significant, and thus were eliminated from the model. Some years of birth were associated with higher hazard ratio than others, especially 2021, when mortality was 3.007 times higher than in 2018. Health treatments were associated with increased hazard of culling in the following 3 mo. The average effect of line over all life stages was significant, with the high_LGV line having a decreased risk of culling (hazard ratio 0.63; CI = 0.465; 0.864).

DISCUSSION

Several studies estimated heritability of functional longevity [START_REF] Castañeda-Bustos | Linear and nonlinear genetic relationships between type traits and productive life in US dairy goats[END_REF][START_REF] Nayeri | Genome-wide association study for lactation persistency, female fertility, longevity, and lifetime profit index traits in Holstein dairy cattle[END_REF][START_REF] Palhière | Functional longevity is heritable and controlled by a major gene in French dairy goats[END_REF] to be around 10% in goats. Nevertheless, there was a need to check if a hyperselection on functional longevity done on the commercial population would translate into significant differences in longevity in a common farm environment with direct Total milk yield estimation with Fleishmann method using test-day records of each in 90 or 250 DIM lactation period. Differences in functional longevity between farms will be heavily influenced by the level of challenge encountered in the different farming environments (e.g., farmer culling rules and environment harshness). Moreover, 2 animals can have the same functional lifespan, but one can receive considerably more medicinal interventions throughout its lifetime and thus be less robust. Such a selection for functional longevity was run on rabbits and led to significant difference in longevity [START_REF] Garreau | Divergent selection for longevity in breeding does: Indirect response for energy balance and fat stores[END_REF]. To our knowledge, selection on longevity has never been done in dairy ruminants.

Our finding that hyperselection for functional longevity resulted in increased survival was observed in a single breed (Alpine) and in a single experimental herd over 5 yr with a management representative to that found in many commercial dairy goat farms (i.e., indoors, feeding forage and concentrate, using AI and twice day milking). According to the national performance-recording database, the average milk yield for first lactation Alpine goats over 250 d was 707 kg in 2019 [START_REF] Thomas | Idele -Milk recording results of goats -France Year 2019[END_REF]. In the present study, milk yield (± SD) was 619.6 kg (± 121.2) on a 250-d basis (Fleischmann's method). In the national database, the average LSCS in Alpine goats was 5.34 (± 1.59) compared with 4.74 (± 2.05) in the present study. The survival advantage of the high_LGV line was consistent between years, even though mortality rates and environment conditions (i.e., forage quality, infectious pressure) varied.

This study showed that it is possible to get a selection response for functional longevity in goats despite a low heritability. The high_LGV median survival time was 830 d compared with 787 d for low_LGV line (difference = 43 d), showing that there was a strong delay in involuntary culling achieved by selection. This difference is, however, lower than what we estimated based on the length of productive life of the AI bucks' daughters (1,071 d for the high_LGV and 909 for the low_LGV line, difference = 162 d). That can be explained, at least to some extent, by the fact that the genetic evaluation of bucks was run only on their daughters that had a registered milk yield (i.e., the ones that survived the first unproductive year of life). Indeed, the life expectancy for goats that survived the first year was 1,498 d for the high_LGV compared with 1,097 d for the low_LGV line (difference = 401 d). The survival analysis confirmed that the line effect was not constant over the life of the animal. The 2 lines had the same survival during the first 15 mo, whereas the high_LGV line had a better survival thereafter. This finding could be explained by the fact that the environmental challenges that affect the first year (e.g., overcoming birth, dealing with milk feeding and its related health effects, building an immunocompetence) are different than those faced by adults. Survival after the first year could rely on mechanisms that are not expressed before the first year. Further, some factors that would otherwise be present throughout the life of the animal, such as malformations and inappropriate body morphology, will be culled out soon after birth. In cattle, [START_REF] Pritchard | Understanding the genetics of survival in dairy cows[END_REF] found a positive genetic correlation (0.31) between heifer survival and lifespan score. The relatively low correlation suggested that survival in the rearing herd and the milking period are different traits. The small number of goats included in our study did not permit calculation of genetic correla- tions. However, our results highlighted the need to record culling information before first kidding of goats on a national scale to address that issue. Indeed, survival at early stage of life has been shown to be heritable in sheep [START_REF] Riggio | Genetic parameters for early lamb survival and growth in Scottish Blackface sheep[END_REF].

Low serum immunoglobulin concentration shortly after birth was correlated with lower survival through life (P = 0.03). It has been shown that a lower passively acquired immunity is linked with an increase of diarrhea, lower weight gain, and increased mortality during the first month [START_REF] Bekele | Influence of passively acquired colostral immunity on neonatal lamb mortality in Ethiopian highland sheep[END_REF][START_REF] Berge | Evaluation of the effects of oral colostrum supplementation during the first fourteen days on the health and performance of preweaned calves[END_REF]. Here, we showed that the deleterious effect of impaired immune transfer from colostrum remained even during subsequent stages of life. In our study, all kids were given the same amount (300 mL) of heat-treated colostrum sampled from a group of kidding goats. The variability of IgG absorption could be due to a difference in IgG concentration in colostrum pools (not standardized among samples), time before ingestion [START_REF] Weaver | Passive transfer of colostral immunoglobulins in calves[END_REF], heating time [START_REF] Saldana | Effect of different heating times of high-, medium-, and low-quality colostrum on immunoglobulin G absorption in dairy calves[END_REF], or difference of first milk coagulation that could affect intestinal absorption [START_REF] Miyazaki | Short communication: Neonatal calves coagulate first-milking colostrum and produce a large curd for efficient absorption of immunoglobulins after first ingestion[END_REF].

First lactation milk yield was similar for both lines. This confirmed that the selection procedure resulted in differences in functional longevity (i.e., longevity corrected for milk yield). No line difference was found for the number of kiddings per adult year nor in litter size. Thus, the better survival of the high_LGV line seemed neither to be due to better production nor better fertility.

The SCS score for first lactation was higher for low_ LGV than high_LGV goats. This result was consistent with the slight difference in EBV for SCS in the sire bucks that could not be avoided when choosing extreme founders. That might mean a better udder health of high_LGV goats [START_REF] Poutrel | Cell content of goat milk: California mastitis test, coulter counter, and fossomatic for predicting half infection[END_REF][START_REF] Contreras | Physiological threshold of somatic cell count and California mastitis test for diagnosis of caprine subclinical mastitis[END_REF][START_REF] Jiménez-Granado | Factors affecting somatic cell count in dairy goats: A review[END_REF][START_REF] Rupp | Divergent selection on milk somatic cell count in goats improves udder health and milk quality with no effect on nematode resistance[END_REF]. There was no significant difference between lines concerning the number of treatments received. Indeed, despite treatment events significantly reducing survival over the 3 following months, including the treatment in the model did not affect the line effect. Although we cannot exclude the possibility that there were undetected disease events at play (affecting one line more than the other), the better survival of the high_LGV line suggested that in some way this line was more resilient to environmental perturbations. In this context, it is interesting to note that several studies found genetic correlations between functional longevity and udder traits in cows and goats. [START_REF] Palhière | Functional longevity is heritable and controlled by a major gene in French dairy goats[END_REF] found genetic correlations of functional longevity with milk SCS (from -0.29 to -0.35), rear udder attachment, and udder floor position (from 0.17 to 0.29). Such genetic associations of functional longevity with SCS were also reported in cattle [START_REF] Sasaki | Estimation of genetic parameters for longevity traits in dairy cattle: A review with focus on the characteristics of analytical models[END_REF] and in goats [START_REF] Castañeda-Bustos | Linear and nonlinear genetic relationships between type traits and productive life in US dairy goats[END_REF].

The month-per-month survival modeling allowed us to precisely implement the effect of events that occurred at different ages of the animal, or evolving variables such as treatments and BW. A strong correlation between survival and speed of growth was found during the first year. Several studies have found that kids (or lambs) with the lowest weight have a lower chance of survival [START_REF] Riggio | Genetic parameters for early lamb survival and growth in Scottish Blackface sheep[END_REF][START_REF] Dwyer | Invited review: Improving neonatal survival in small ruminants: Science into practice[END_REF][START_REF] Chauhan | Survival analysis of mortality in pre-weaning kids of Sirohi goat[END_REF] that could be partly attributed to the increased risk of hypothermia, which has been related to size as well as the individual's fat reserves [START_REF] Alexander | Temperature regulation in the new-born lamb. V. Summit metabolism[END_REF]. Moreover, smaller kids are penalized in all aspects of social competition.

It is interesting that the monthly growth rate (obtained from the B-spline smoothing) was more correlated with survival than BW. As a measure, growth rate is inherently more responsive to environmental challenges than is BW per se (a strong disease or nutritional challenge can cause growth rate to shift from positive to negative, whereas the corresponding change in BW is proportionally far less due to the cumulative nature of the measure). This finding suggested that the influence of growth rate on survival is associated with ability to cope with underlying disease or stress challenges. Several studies reported a negative correlation between growth rate and longevity [START_REF] Hou | The energy trade-off between growth and longevity[END_REF]) and proposed that higher growth rate implies higher oxidative stress and shorter longevity [START_REF] Jimenez | The same thing that makes you live can kill you in the end": Exploring the effects of growth rates and longevity on cellular metabolic rates and oxidative stress in mammals and birds[END_REF]. We found no differences between lines during the first year in growth rate and BW. Moreover, no carryover effect of the average growth rate during the first year on later survival was found.

The high_LGV goats were heavier during early lactation (between 12 and 16 mo). Because the body morphology records were less frequent than weighing and highly correlated with it, we did not include them in the survival analysis. However, the comparison of height and chest size between lines was of interest. No differences concerning the height at the withers was found, and high_LGV goats seemed to have a slightly wider chest (P = 0.03), indicating that high_LGV goats might have larger lipid reserves. In addition, the fatto-protein ratio in milk during the first month of the first lactation was higher for the low_LGV line. This suggested that this line had a greater negative energy balance in early lactation [START_REF] Bocquier | Somatic cell count-based selection reduces susceptibility to energy shortage during early lactation in a sheep model[END_REF], despite milk yield being similar between lines during this critical period, and no differences in litter size or litter weight. These findings taken together tended to suggest that there were different resilience capacities between the lines, with different underlying priorities for usage of body lipid reserves. This may have contributed to the differences in functional longevity between them. The argument that body fatness dynamics confer robustness and help underpin resilience responses is supported by several studies. [START_REF] Savietto | Reproductive robustness differs between generalist and specialist maternal rabbit lines: The role of acquisition and allocation of resources[END_REF] showed that rabbits selected for productive longevity had a greater capacity for resources acquisition under constrained condition than rabbits selected for reproductive intensity. In cattle, body reserves have been shown to be predictive for reproduction and susceptibility to disease; excessive BCS at calving and great loss of BCS during early lactation were related to increased health disorders [START_REF] Roche | Invited review: Body condition score and its association with dairy cow productivity, health, and welfare[END_REF][START_REF] Roche | Assessing and managing body condition score for the prevention of metabolic disease in dairy cows[END_REF]. In dairy sheep, a divergent selection experiment for mastitis resistance was performed and showed a genetic link between susceptibility to udder infections and metabolic adaptation to energy shortage (Bouvier-Muller et al., 2018). However, the underlying mechanisms of the link between resilience, the dynamics of fat reserves, and BCS remain unclear.

The suggestion that the differences between low_ LGV and high_LGV lines may be related to differences in body reserve dynamics, and thus resilience, merits further study. Studies with more intensive recording of BW, BCS and energy metabolism, as well as ingestion should be of great value to explain different lifetimes of the 2 hyperselected lines of goats.

CONCLUSIONS

Hyperselection based on functional longevity of AI bucks successfully created 2 groups of goats with different lifespans. Monitoring of the lines indicated that functional longevity-based selection was associated with resilience-related mechanisms, as evidenced by better udder health with decreasing milk cell counts. In addition, the higher BW of high_LGV goats and lower milk fat-to-protein ratio during the beginning of the first lactation suggested different resource allocation profiles between lines. Our results supported the hypothesis that functional longevity reflects the accumulated consequences of resilience and thus provides a proxy measure for resilience.

  Ithurbide et al.: LONGEVITY-BASED DIVERGENT SELECTION IN GOATS

  Ithurbide et al.: LONGEVITY-BASED DIVERGENT SELECTION IN GOATS Journal of Dairy Science Vol. 105 No. 5, 2022

  Figure 1. Distribution of culling reasons that occurred before and after 365 d of age in the high longevity (high_LGV; n = 111 goats) and low longevity (low_LGV; n = 135 goats) lines.

  Ithurbide et al.: LONGEVITY-BASED DIVERGENT SELECTION IN GOATS

5

  Ratio of fat content to protein content calculated for the first test day in lactation (between 1 and 45 DIM).6Serum immunoglobulin concentration during the first days of life. *0.01 < P < 0.1; **P < 0.01.

Figure 2 .

 2 Figure 2. Distribution of treatment reasons that occurred before and after 365 d of age in the high longevity (high_LGV) and low longevity (low_LGV) lines.

  Figure 3. (A) Smoothed weight curves of the 341 goats from birth to 12 mo. (B) First derivative of the smoothed weight curves of the 341 goats from birth to 12 mo.

Figure 4 .

 4 Figure 4. Plot of Kaplan-Meier curve showing survival against time for high longevity line (high_LGV) and low longevity line (low_LGV). Shaded areas represent the 95% confidence intervals calculated by Cox analysis.

  Figure 5. Plot of scaled Schoenfeld residuals against transformed event time for Cox proportional hazards model for line covariable. The effect of the high longevity line (high_LGV) compared with the low longevity line is represented. The solid curve is the smoothed LOESS curve of β(t), and broken lines represent the 95% confidence intervals. β(t) corresponds to the estimation of the hazard ratio associated with high_LGV compared with the low longevity line at age t. The green broken line corresponds to the average high_LGV line effect estimated by the Cox model. The slope suggests violation of the proportional hazards assumption for the line effect.

Table 1 .

 1 Ithurbide et al.: LONGEVITY-BASED DIVERGENT SELECTION IN GOATS Estimated breeding values for length of functional life and production traits for 35 bucks that sired the high longevity (high_LGV; n = 16) and low longevity (low_LGV; n = 19) lines; the contemporary bucks (n = 228) were chosen with minimum of 100 progeny tested daughters (228 bucks)

	Trait 1

Table 2 .

 2 Distribution of the 440 goats within the 2 lines selected on high longevity (high_LGV) or low longevity (low_LGV) bred at INRAE facility of Bourges between 2017 and 2021

			Year of birth of each cohort
	Item	2017	2018	2019	2020	2021	Total
	low_LGV	48	46	39	40	39	212
	high_LGV	45	45	42	68	28	228
	Total	93	91	81	108	67

Table 3 .

 3 The ANOVA testing for the difference between lines (LSM or odds ratio) for the high longevity (high_LGV) and low longevity (low_LGV) divergent goat lines

		high_LGV line	low_LGV line	Analysis of variance
		No. of	Mean	No. of	Mean
	Item	records	(SD)	records	(SD)	P-value
	Percentage of culling at the end of the study	228	49.5 (3.1)	212	62.4 (3.1)	0.004**
	Number of treatments per year	228	0.23 (0.04)	212	0.3 (0.05)	0.13
	Kidding per adult year (odds ratio)	140	1.03 (0.19)	136	0.96 (0.20)	0.70
	Number of kids per kidding	130	1.38 (0.05)	117	1.43 (0.06)	0.58
	Weight at birth (kg)	228	3.77 (0.08)	212	3.88 (0.08)	0.33
	Weight (kg)	5,813	42.5 (0.26)	5,790	42.3 (0.26)	0.50
	Line effect nested per month Mean dWD (SD) 1 Mean WD (SD) 2 LSCS 3 MY90 4 MY250 4 Milk fat-to-protein ratio 5 Log(Ig) 6	175 169 109 109 109 105 199	-0.11 (0.06) -0.08 (0.09) 4.44 (0.17) 256 (5.12) 613 (11.6) 0.95 (0.02) 1.90 (0.05)	166 161 106 106 106 101 183	-0.07 (0.06) -0.11 (0.09) 4.94 (0.18) 262 (5.28) 624 (11.9) 1.00 (0.02) 1.97 (0.05)	0.002** 0.57 0.77 0.04* 0.43 0.54 0.07* 0.30
	Chest size (cm)	1,130	83.7 (0.34)	1,022	83.0 (0.34)	0.03*
	Height (cm)	1,130	71.0 (0.29)	1,022	70.9 (0.29)	0.69

1 Mean speed of growth deviation during the first year of life. 2 Mean weight deviation during the first year of life. 3 Adjusted SCS.

4

Table 4 .

 4 The ANOVA testing for the difference of weight between high longevity (high_LGV) and low longevity (low_LGV) divergent goat lines 1

		low_LGV		high_LGV
	Month of age	Weight, kg	SD	Weight, kg	SD	P-value
	0	8.0	0.375	8.1	0.370	0.826
	1	13.2	0.390	13.3	0.385	0.772
	2	18.6	0.395	18.9	0.394	0.560
	3	23.5	0.399	23.9	0.404	0.415
	4	27.0	0.398	26.8	0.394	0.676
	5	30.4	0.406	30.5	0.403	0.861
	6	32.1	0.417	32.4	0.411	0.641
	7	34.1	0.439	33.9	0.442	0.582
	8	37.0	0.502	36.8	0.504	0.776
	9	37.3	0.499	37.1	0.556	0.677
	10	41.6	0.574	41.6	0.643	0.931
	11	41.3	0.570	40.7	0.712	0.478
	12	43.1	0.508	43.4	0.513	0.660
	13	41.8	0.478	43.4	0.470	0.003*
	14	40.9	0.497	42.1	0.499	0.032*
	15	43.4	0.785	45.1	0.663	0.089
	16	46.5	0.484	48.0	0.482	0.006*
	17	46.0	0.527	46.4	0.546	0.568
	18	48.5	0.847	49.2	0.777	0.525
	19	48.1	0.847	48.2	0.741	0.856
	20	49.6	0.816	49.9	0.792	0.763
	21	49.6	0.485	50.2	0.495	0.339
	24	54.7	0.643	57.2	0.585	0.001*
	25	55.2	0.659	53.1	0.618	0.011*
	26	55.1	0.818	53.7	0.676	0.193
	28	58.8	1.114	56.9	0.821	0.157
	33	60.0	0.814	58.1	0.799	0.086
	34	57.5	0.778	58.1	0.715	0.605
	36	64.7	0.771	65.5	0.667	0.427
	37	61.9	1.057	60.2	0.753	0.177

longevity recording. Given the differences in the relative importance of different mechanisms contributing to survival in different environments, lifespan is likely to be affected by genetics × environment interactions.

Table 5 .

 5 Hazard ratios (HR) with 95% lower and upper CI from Cox hazard model for culling data in 440 goats of the high longevity (high_LGV) and low longevity (low_LGV) lines

	Risk factor	HR	CI		P-value
	high_LGV line vs. low_LGV	0.645	0.474	0.878	0.005
	Birth year 2017 vs. 2018	1.453	0.971	2.176	0.069
	Birth year 2019 vs. 2018	1.456	0.915	2.316	0.113
	Birth year 2020 vs. 2018	1.072	0.576	1.996	0.826
	Birth year 2021 vs. 2018 d_WD 1 Health treatment vs. none 2 High IgG concentration 3	3.016 0.328 2.029 0.687	1.523 0.251 1.315 0.492	5.973 0.427 3.128 0.960	0.002 <0.001 0.001 0.028
	1 Speed of growth deviation (d_WD) is the normalized value of the first derivative of the weight curve and is
	implemented each month between 1 and 13 mo.

LPL = length of productive life. Genetic evaluation for longevity was run on May

2021; genetic evaluation for milk yield, SCC, and body morphology was run on January 2021. Journal of Dairy Science Vol. 105 No. 5, 2022

Journal of Dairy Science Vol. 105 No. 5, 2022

The animal was included in the model as a random effect. The line effect was nested into month of age. Results are averaged over the levels of year, gestation, and kidding. *0.01 < P < 0.1.

Health treatment is a dummy variable = 1 if the animal received a treatment in the past

mo and 0 if else.3 Log-transformed serum immunoglobulin concentration during first days following birth [Log(IgG)] is a permanent effect over whole life. High group corresponds to a value higher than 2 and is compared with goats with values lower than 2.Journal of Dairy Science Vol. 105 No. 5, 2022

ACKNOWLEDGMENTS

The authors thank the staff of the INRAE experimental unit at Bourges, France, for technical support in producing, raising, and monitoring the animals. This work was performed in the framework of the EU H2020 SMARTER project (grant no. 772787, Castanet Tolosan, France) and the national APIS-GENE (Paris, France) funded projects ActiveGoat and Resilait. M. Ithurbide acknowledges EU H2020 (SMARTER) and APIS-GENE (Resilait) for her PhD grant. The authors have not stated any conflicts of interest.