Alice De Boyer Des Roches
email: alice.deboyerdesroches@vetagro-sup.fr

Isabelle Veissier

Xavier Boivin

Emmanuelle Gilot-Fromont

Luc Mounier

A prospective exploration of farm, farmer, and animal characteristics in human-animal relationships: An epidemiological survey

Keywords: human-animal relationships, animal welfare, dairy cow, farmer's attitude

Human-animal relationships are essential for dairy farming. They affect work comfort and efficiency, as well as milk production. A poor human-animal relationship can result in stress and accidents to both animals and caretakers and needs to be improved. However, many studies have demonstrated the multifactoriality of these relationships. We aimed at assessing the relative importance of the various factors expected to be associated with poor human-animal relationships. On 118 dairy farms, we applied a standardized avoidance distance test to cows at the feeding rack. The sample of farms covered a wide range of situations: lowland versus highland, small versus medium size farms, cubicles versus deep-bedded systems, milking parlor versus automatic milking systems, and Holstein versus Montbéliarde breeds. We used Poisson regression to analyze the links between the number of cows that accepted being touched, and farm characteristics, animals, management, and farmers' attitudes. A multivariate analysis yielded a final model that explained 32.7% of the variability between farms. Calving conditions ("Main calving location" and "Cleaning or adding litter after calving") accounted for a significant part of the variability observed (respectively 25.8 and 13.6% of variability explained by the model, SSB). Fewer cows accepted being touched on farms where the main calving location was in the barn, and where farmers cleaned or added litter after calving. The proportion of cows that accepted being touched increased with the proportion of lean cows in the herd (18.8%), with worker/cow ratio on the farm (11.7%), when farmers considered "health" or "human-cow relationships" as most impor-tant issues for farm success (10.4%), and with farmers' years of experience (10.8%). Farmers with more negative behavioral attitudes toward cows had a lower proportion of cows that accepted being touched (8.9%). In conclusion, the human-animal relationship was not found to be associated with farm characteristics (e.g., housing or milking system) but varied with farmers' attitudes and management. We confirm that cows' fear of people is linked to negative attitudes displayed by caretakers toward cows, and is reduced in farms where several caretakers are present. Our study also suggests further exploring the key role of factors linked to calving conditions, as cows are more likely to be afraid of people when disturbed at calving.

INTRODUCTION

In most farming conditions, animals are in contact with humans, so human-animal relationships are essential for farmers and other stakeholders. In the dairy industry, poor human-animal relationships result in low work comfort and efficiency, are associated with reduced milk production, and can result in accidents to both animals and caretakers [START_REF] Rushen | Domestic animals' fear of humans and its effect on their welfare[END_REF][START_REF] Hemsworth | Human contact[END_REF][START_REF] Kallioniemi | Safety and animal handling practices among women dairy operators[END_REF]. Good human-animal relationships are also essential for animal welfare because they affect animals' emotions, such a fear during rough handling. The current intensification of dairy systems in Western countries, associated with larger herds and less human contacts, may even worsen human-cattle relationships if the only contacts are aversive [START_REF] Waiblinger | Influence of herd size on human cow relationships[END_REF].

The human-animal relationship is defined as the mutual perception of the animal and the human, reflected in their mutual behaviors [START_REF] Waiblinger | Assessing the humananimal relationship in farmed species: A critical review[END_REF]. Several factors are associated with variations in humananimal relationships at individual and herd levels (European Food Safety Authority, 2009). Cattle's reactions to humans depend on their previous experiences with humans [START_REF] Seabrook | The psychological interaction between the stockman and his animals and its influence on performance of pigs and dairy cows[END_REF][START_REF] Boivin | Beef calves react differently to different handlers according to the test situation and their previous interactions with their caretaker[END_REF][START_REF] Breuer | Behavioural response to humans and the productivity of commercial dairy cows[END_REF][START_REF] Hemsworth | Relationships between human-animal interactions and productivity of commercial dairy cows[END_REF] and especially on the behavior of caretakers when they interact with animals [START_REF] Hemsworth | Human-Livestock Interactions: The Stockperson and the Productivity and Welfare of Intensive Farmed Animals[END_REF]. The behavior of caretakers is strongly influenced by their attitudes. As defined by [START_REF] Eagly | The psychology of attitudes[END_REF], an attitude is a "psychological tendency that is expressed by evaluating a particular entity with some degree of favor or disfavor." Attitudes can be cognitive (beliefs about animals, e.g., one can believe that cows are dangerous) or behavioral (tendency to behave in a particular way, e.g., some caretaker may consider that animals need to be handled gently), and are generally linked to job satisfaction (the degree of comfort one feels in different tasks; [START_REF] Hemsworth | Human-Livestock Interactions: The Stockperson and the Productivity and Welfare of Intensive Farmed Animals[END_REF]. Attitudes are assessed through interviews and questionnaires (e.g., a behavioral attitude is often assessed by asking how frequently someone produces a given behavior; [START_REF] Hemsworth | Human-Livestock Interactions: The Stockperson and the Productivity and Welfare of Intensive Farmed Animals[END_REF]. Farmers' behavior depends also on gender, with women showing more positive behavior than men [START_REF] Lensink | The relationship between farmers' attitude and behaviour towards calves, and productivity of veal units[END_REF]. Beside the type of interactions with the animal, the time at which they occur is essential. Handling is determining for humananimal relationships at 3 periods: early life [START_REF] Jago | The influence of feeding and handling on the development of the human-animal interactions in young cattle[END_REF][START_REF] Probst | Gentle touching in early life reduces avoidance distance and slaughter stress in beef cattle[END_REF][START_REF] Schütz | Effects of human handling during early rearing on the behaviour of dairy calves[END_REF], weaning [START_REF] Boivin | Establishment of cattle-human relationships[END_REF][START_REF] Fukasawa | Calf training for loading onto vehicle at weaning[END_REF], and parturition (Hemsworth et al., 1989b).

The animals themselves have an effect on their relation with humans. More specifically, genetic factors seem to play a key role. Animals' reactivity is inheritable [START_REF] Grandin | Genetics and behavior during handling, restraint and herding[END_REF], and large differences are present both between dairy and beef breeds [START_REF] Murphey | Approachability of bovine cattle in pastures: Breed comparisons and a breed×treatment analysis[END_REF][START_REF] Murphey | Responses of cattle to humans in open spaces: Breed comparisons and approach-avoidance relationships[END_REF], and between individuals within a beef cattle breed [START_REF] Haskell | Genetic selection for temperament traits in dairy and beef cattle[END_REF]. However, to date, no difference in the human-animal relationships has been reported among dairy breeds [START_REF] Waiblinger | Influences on the avoidance and approach behaviour of dairy cows towards humans on 35 farms[END_REF], but this last study did not include the Holstein breed. The age of animals can also affect human-animal relationships, but with strong variations between dairy farms, the easiest cows to approach are either the youngest or the oldest [START_REF] Waiblinger | Influences on the avoidance and approach behaviour of dairy cows towards humans on 35 farms[END_REF]. The health status of animals may also affect their responses to humans: lame cows are easier to approach, whereas the opposite is observed in cows with mastitis [START_REF] Mülleder | Methodological aspects for the assessment of social behaviour and avoidance distance on dairy farms[END_REF][START_REF] Ivemeyer | Effect of human-animal relationship and management on udder health in Swiss dairy herds[END_REF]. Some production indicators such as total milk yield, milk fat, and milk proteins over lactation are associated with human-animal relationships [START_REF] Breuer | Behavioural response to humans and the productivity of commercial dairy cows[END_REF]European Food Safety Authority, 2009), but to date, the association between the nutritional status of dairy cows and human-animal relationships has not been studied. Finally, the social context of animals within the group is also linked to human-animal relationships: the higher the cohesion in the group as shown by frequent positive encounters between animals (such as licking) and rare aggressions, the more readily the animals approach humans [START_REF] Waiblinger | Influences on the avoidance and approach behaviour of dairy cows towards humans on 35 farms[END_REF].

Several authors argue that farm characteristics and the way animals are managed affect their relation to humans [START_REF] Boivin | Influence of breed and rearing management on cattle reactions during human handling[END_REF]. [START_REF] Grandin | How to Improve Livestock Handling and Reduce Stress. Improving Animal Welfare, A Practical Approach[END_REF] highlights the importance of handling facilities for interventions on cattle on subsequent cattle stress during handling. Other factors such as herd size and work organization can affect caretaker behavior [START_REF] Waiblinger | Influence of herd size on human cow relationships[END_REF][START_REF] Lensink | The relationship between farmers' attitude and behaviour towards calves, and productivity of veal units[END_REF][START_REF] Seabrook | The effect of the operational environment and operating protocols on the attitudes and behaviour of employed stockpersons[END_REF][START_REF] Hemsworth | Human-Livestock Interactions: The Stockperson and the Productivity and Welfare of Intensive Farmed Animals[END_REF] and in turn the human-animal relationships. For instance, the larger the farm, the less time is spent with the cows, and the more difficult cows are to approach [START_REF] Waiblinger | Influence of herd size on human cow relationships[END_REF][START_REF] Waiblinger | Influences on the avoidance and approach behaviour of dairy cows towards humans on 35 farms[END_REF].

However, the respective roles of farm characteristics, animals, management, and farmers' attitudes in human-animal relationships remain to be disentangled. The aim of the present epidemiological study was to estimate to what extent these factors are statistically associated with variation in human-dairy cow relationships, assessed through avoidance reactions of cows. Such information is crucial to develop intervention strategies in dairy farms and to improve human-animal relationships and safety of both humans and animals. We chose an epidemiological approach to take full account of the diversity of the situations.

MATERIALS AND METHODS

A total of 118 commercial dairy farms were visited in 2 French regions (lowlands in Western France-Brittany and Pays de Loire-versus highlands in central and eastern France-Auvergne and Rhône-Alpes). All the farms were family-run, had loose-housing systems (cubicles or deep-bedding barns), and used a milking parlor or an automatic milking system (AMS). All the farms belonged to a milk control organization. Herd size ranged from 21 to 120 dairy cows, and cows were of Montbéliarde (French dual-purpose breed) or Holstein breeds. The farms had been selected at random from exhaustive, anonymous lists provided by the French Health Prevention Group ("Groupement de defense sanitaire"). Random sampling was performed using R 2.15.2 software (R Development Core Team, 2009). Each farm was visited once. The organization of the farm visit followed the Welfare Quality protocol (Welfare Quality, 2009). Five observers carried out the visits. They had been trained previously by an associate from the Welfare Quality project. During training 3 on 4 farms, observers' results were compared with each other's and against reference values to ensure reproducibility between observers, and accuracy.

Avoidance Testing at the Feeding Rack

In Welfare Quality, the measure chosen to assess human-animal relationship is cow avoidance reaction at the feeding rack. This method was chosen because the results are closely correlated with other measures of cows' fear reaction such as passing and touching a lying animal and walking through the herd and touching animals: it varies with previous experience of animals with humans, had good intra-and inter-observer reliability, shows good repeatability of the animal's reaction to different people and a good stability over time, and can easily be performed for routine on-farm assessments [START_REF] Waiblinger | Influences on the avoidance and approach behaviour of dairy cows towards humans on 35 farms[END_REF][START_REF] Winckler | Long-term consistency of selected animal-related welfare parameters in dairy farms[END_REF][START_REF] Windschnurer | Reliability and inter-test relationship of tests for on-farm assessment of dairy cows' relationship to humans[END_REF]. We applied the Welfare Quality method both for sampling method and behavioral test. On each farm, only a sample of animals was tested. The size of the sample was defined so as to be representative of the whole group of animals: if 30 or fewer lactating cows were present in a herd, all the animals were tested; otherwise 75 to 45% of cows were randomly chosen, the proportion decreasing with the size of the herd (e.g., 30 cows out of 44, 54 cows out of 120; [START_REF] Windschnurer | Assessment of human-animal relationships in dairy cows[END_REF]. Once the sample size for a farm was decided, the animals were selected at random. The cows were tested at the feeding rack, when all the cows were back in the barn after morning milking. The observer stood at a distance of 2 m in front of the cow to be tested, making sure that the cow was paying attention (not foraging), and noted the individual cow number (ear tag number). The observer then approached the cow at a speed of 60 cm/s with an arm held overhand at an angle of 45° from the body and looking at the cow's muzzle. The observer stopped walking when the cow showed a sign of withdrawal (moved back, turned its head to the side, or pulled back its head), or when the cow could be touched on its muzzle. On each farm, the numbers of cows tested and touched was noted.

Factors Studied

The selection of explanatory factors was based on results from previous studies (as reported in the Introduction above).

The final list consisted of 48 factors split into 4 categories: factors related to the farm, to the management, to the animals, and to the farmer's attitude (Table 1). They were collected during the visit by direct observations, from farm records, or by questioning farmers.

Animal factors were recorded by direct observations or from milking records following the Welfare Quality Protocol (Welfare Quality, 2009). Aggressive interactions (butts and displacements) between cows were recorded by continuous sampling for 1 h after the avoidance test at the feeding rack. Because the frequencies of butts and displacements were strongly correlated (R 2 = 0.87, P < 0.001), we kept only the frequency of displacements per cow per hour for further analyses. After observing the social behavior, we assessed the body condition and gait of each cow; we considered the percentage of very lean cows in a herd (score 1 in Welfare Quality) and the percentage of lame cows (score 1 and 2 in Welfare Quality). From milk recordings, we extracted, for each cow, SCC for the last 3 mo before the visit, parity, number of days since calving, and maximum level of production in the first 3 mo of lactation.

Farmers' personal characteristics, job satisfaction, and attitudes toward cows and working with cows were evaluated using a questionnaire built on the basis of previously published work [START_REF] Breuer | Behavioural response to humans and the productivity of commercial dairy cows[END_REF][START_REF] Lensink | The relationship between farmers' attitude and behaviour towards calves, and productivity of veal units[END_REF][START_REF] Waiblinger | The relationship between attitudes, personal characteristics and behaviour of stock-people and subsequent behaviour and production of dairy cows[END_REF][START_REF] Mounier | Links between specialization in the finishing of bulls, mixing, farmers' attitudes towards animals and the production of finishing bulls: a survey on French farms[END_REF]. We did not observe farmers' behavior with cows because of time constraints and more importantly because behavior can vary from one day to another or due to the presence of the observer. We rather focus on attitudes, which, according to the theory of reasoned action, are supposed to reflect the farmer's tendency to behave in a certain way [START_REF] Ajzen | Understanding Attitudes and Predicting Social Behaviour[END_REF]. Hence, we used indicators of behavioral attitudes because they are good predictors of farmers' average behavior toward animals in different species including cattle (Hemsworth et al., 1989a;[START_REF] Lensink | The relationship between farmers' attitude and behaviour towards calves, and productivity of veal units[END_REF][START_REF] Waiblinger | The relationship between attitudes, personal characteristics and behaviour of stock-people and subsequent behaviour and production of dairy cows[END_REF][START_REF] Hemsworth | Human-Livestock Interactions: The Stockperson and the Productivity and Welfare of Intensive Farmed Animals[END_REF]. We chose to limit the questionnaire to 32 questions subdivided into 5 parts: 2 questions on gender and years of experience working with cows; one question on the issue farmers considered the most important for farm success; 8 questions on job satisfaction (in the form of "How much do you like x?" where x was an action such as "cleaning the barn" or "being with dairy cows"); 8 questions on cognitive attitudes (in the form of "Do you agree with x?" where x was a statement such as "cows are sensitive to the contact with farmer" or "cows have a good memory"); and 13 questions on behavioral attitudes (in the form of "how often do you x?" where x was an action such as "talk to cows" or "yell at cows"). The responses to questions on job satisfaction and attitudes were scored on a 1 to 10 scale where 1 corresponded to "I do not like x"/"I do not agree with x"/"I never do x," whereas 10 corresponded to "I like x very much")/"I completely agree with x")/"I always do x" (for job satisfaction/ cognitive attitudes/behavioral attitude, respectively).

The farms were managed by 1 to 4 persons. If the farm was managed by more than one person, the questionnaire was filled in by the person working the most with the cows, called the farmer in the present paper. This person was responsible of the daily management of the cows (food distribution, barn cleaning, cow milking).

Statistical Analyses

In all analyses, the observational unit was the farm. First, to summarize the data on farmers' attitudes, we ran principal component analyses (PCA) for each category of attitudes (job satisfaction, cognitive and behavioral attitudes). We focused on axes that had an eigenvalue higher than 1. To interpret these axes, we took into account variables with a contribution of absolute value higher than 0.3. We used the 1st and 2nd axis synthetic variable to summarize attitudes.

We then modeled the number of cows touched during the avoidance test per farm with a Poisson generalized linear model (GLM). Poisson regression let us adjust the number of cows touched during the test per farm for sample size (i.e., number of cows tested per farm) by using the total number of cows tested per farm as an offset variable [START_REF] Dohoo | Veterinary Epidemiologic Research[END_REF]. To analyze the links between the 48 factors studied and the number of cows touched during the avoidance test, we first used univariate GLM. The factors with a probability of effect of 0.05 or less were kept to build a multivariate full model. The full model was then simplified by backward elimination according to the Akaike information criterion (AIC) [START_REF] Akaike | Information theory and an extension of the maximum likelihood principle[END_REF]. The simplification was stopped when no factor that would decrease the AIC value could be removed [START_REF] Burnham | AIC model selection and multimodel inference in behavioral ecology: Some backgrounds, observations, and comparisons[END_REF]. The chosen model was analyzed using likelihood ratio tests for the effect of factors and Wald tests for the contrast between modalities. Finally, among models with close AIC values (∆ < 2), we selected the most parsimonious (i.e., the model with the fewest parameters). The normal distribution of residuals was checked with a Shapiro-Wilk test, and the homogeneity of variance was checked with a Levene test.

Analyses were performed using the software R 2.15.2 (R Development Core Team, 2009). Package ade4 was used for PCA and package Mass for model simplification. We will comment on results for which P ≤ 0.05.

RESULTS

Details of farm, management, animal and farmer characteristics of the 118 farms and results of univariate analysis are presented in Supplemental Materials (http://dx.doi.org/10.3168/jds.2015-10633).

The 118 farms had a median herd size of 54.4 lactating cows (minimum, 23; maximum, 125), and we tested a median of 36.5 (minimum, 23; maximum, 60) cows per farm. On 18 farms (15.3% of the farms), no cow accepted being touched when approached at the feeding rack. On 64 farms (54% of the farms), fewer than 10% of the cows could be touched. The median was 9.10% of the cows touched by the observer (minimum, 0.0%; maximum, 35.0%; Figure 1). No farm was found to mistreat animals: even on the 18 farms where no cows could be touched, cows could still be approached at less than 2 m and these farms had a median score of 33.3 (minimum, 21.8; maximum, 56.3) on the 0 to 100 scale defined by Welfare Quality, which is higher than 20, the limit for acceptability.

Principal Component Analyses on Farmers' Attitudes

The results of PCA analyses are detailed in Table 2. For job satisfaction, axes 1 and 2 explained 28.7 and 15.4% of the total variance, and they can be summarized as an axis for satisfaction during "barn work" (axis 1, the farmer enjoys adding litter in the barn, cleaning the barn, milking cows, and milking constraints) and satisfaction during "work with animals" (axis 2, the farmer enjoys being with dairy cows, taking care of calves, the farmer dislikes sending a cow to the slaughterhouse). On both axes, the higher the score, the higher the level of satisfaction. For cognitive attitudes, axes 1 and 2 explained 32.0 and 14.9% of the total variance, and they can be summarized by "belief in cows having cognitive capacities" (axis 1, cows are sensitive to contact with the farmer, cows are sensitive to pain, cows have a good memory, and cows recognize the farmer, with high scores corresponding to the belief that cows have high cognitive capacities), and "belief in cows being more sensitive to barn comfort versus persons" (axis 2, with high values correspond to beliefs that cows are more sensitive to the quality of the walking floor, and of the resting floor than to the contact with people other than the farmer). For behavioral attitudes, axes 1 and 2 explained 20.0 and 14.3% of the total variance and can be summarized by "gentle behaviors" (axis 1, the farmer warns cows before preparing the udder for milking, strokes cows, lets calves suck his/her fingers, lets cows smell him/her, and talks to cows), with high values corresponding to frequent gentle behaviors, and "negative behaviors" (axis 2, the farmer kicks cows, hits them on the muzzle, yells at cows, hits cows with a stick, with high values corresponding to frequent negative behaviors).

Univariate Analyses

A total of 19 factors had P < 0.05 in the univariate analyses (Table 3).

Farms with a higher proportion of cows touched were observed when cattle were the only animal production species on the farm (P = 0.007), when the milking system was an AMS (P = 0.023), when cows produced more than 6,000 L of milk per year per cow on average (P = 0.027), when the level of aggression among cows was low (P = 0.011), when cows were at their 4th month of lactation on average (P = 0.016), when less than 30% of cows had mastitis in the herd (P = 0.005), when more than 45% (P = 0.0023) or less than 30% (P = 0.015) of very lean cows were present in the herd, when more than 3 people worked with cows (P < 0.001), when more than one person was working with 20 cows (P < 0.001), when the time spent milking per cow was longer than 3 min (P = 0.002) or when an AMS was present (P < 0.001), when calving took place in pasture (P = 0.026) or in a separate pen (P < 0.001), when farmer reported not often cleaning the calving location/adding litter after calving (P < 0.001), when no hoof disinfection facilities were present (P = 0.024), when the farmer had more than 10 yr of experience (P ≤ 0.029 for the 3 modalities), when the main milker was a woman (P = 0.011), when the issue farmers considered the most important for farm success was "health" (P = 0.028), when farmers reported enjoying "barn work" (P = 0.017) and "work with animals" (P = 0.007), and when they reported seldom behaving negatively toward their animals (P = 0.007).

Multivariate Analysis

Among the 19 significant factors revealed by the univariate analyses, only 7 were kept in the final multivariate model (Table 4). This model explained 32.7% of the variability between farms (likelihood ratio test, P < 0.001). Residuals distribution did not differ from a normal distribution (Shapiro-Wilk normality test, W = 0.99, P = 0.59) and variance was homogenous across groups (Levene's test, P > 0.05 for all factors). The final model had an AIC of 520.69.

Main calving location contributed to 25.8% of the variability explained by the model (i.e., sum of square between classes, SSB), with more cows touched when calving took place in pasture (P = 0.001) or in a separate pen (P < 0.001). Percentage of very lean cows in the herd contributed to 18.8% of the SSB, with more cows touched when the percentage of very lean cows lay between 15 and 30% (P = 0.025) or above 45% (P = 0.002). Cleaning or adding litter after calving contributed to 13.6% of the SSB, with more cows touched when the farmer reported not often cleaning the calving location or adding litter after calving (P < 0.001). The number of persons working with cows/ lactating cow (worker/cow ratio) contributed to 11.7% of the SSB: more cows were touched when more than one person was working for 20 cows (P = 0.009). Farmers' experience contributed to 10.8% of SSB: more cows were touched when the farmer had more than 10 yr of experience (P < 0.05 in all cases). The issue identified as most important for farm success contributed to 10.4% of the SSB, with more cows touched when farmers considered "human-animal relationship" (P = 0.047) or "health" (P < 0.001) as most important for farm success. Farmers' negative behavioral attitude toward cows contributed to 8.9% of the SSB: more cows were touched on farms where the farmer reported seldom or never behaving negatively toward cows (P < 0.001).

DISCUSSION

The scientific literature on factors influencing humancow relationships is very broad, but generally only 1 or 2 factors are explored at a time (e.g., type of interactions with the animal, herd size, animals' health status, farm characteristics, and so on). To our knowledge, this epidemiological study is the first to give a big picture, taking into account all factors (farm characteristics, animals, management, and farmers' attitudes) at the same time. It gives an insight into their relative association with the human-animal relationship, assessed by the percentage of cows touched when approached at the feeding rack in dairy farms where cows are loose-housed. We adopted a cross-cutting epidemiological approach. The findings must therefore be considered with caution: they show association between several factors and human-animal relationships. These associations should not be considered as cause-effects links but raise hypotheses for such links to be tested in controlled studies.

We recorded cows' avoidance reaction at the feeding rack to assess the human-animal relationship. This test, which can be easily performed on farms, was chosen because its validity had been proven by previous studies: avoidance reaction at the feeding rack correlates highly with avoidance distance in the pen (correlation coefficients, 0.82; [START_REF] Windschnurer | Reliability and inter-test relationship of tests for on-farm assessment of dairy cows' relationship to humans[END_REF] and thus seems not to be affected by animal hunger, it is also moderately correlated with reactions of the cows to a human walking through a pen and touching cows standing or lying (correlation coefficients, 0.59 and 0.56; [START_REF] Windschnurer | Reliability and inter-test relationship of tests for on-farm assessment of dairy cows' relationship to humans[END_REF]. In addition, the cow' reaction is similar to different unknown people (between experimenter repeatability: correlation coefficient, 0.87; [START_REF] Windschnurer | Reliability and inter-test relationship of tests for on-farm assessment of dairy cows' relationship to humans[END_REF][START_REF] Windschnurer | Assessment of human-animal relationships in dairy cows[END_REF], and when retested by the same person (test-retest repeatability: correlation coefficient, 0.87; [START_REF] Windschnurer | Reliability and inter-test relationship of tests for on-farm assessment of dairy cows' relationship to humans[END_REF][START_REF] Windschnurer | Assessment of human-animal relationships in dairy cows[END_REF]. This test also showed good stability over time on a 5-mo period [START_REF] Winckler | Long-term consistency of selected animal-related welfare parameters in dairy farms[END_REF]. The validity of this test was confirmed in our study since the results obtained varied with the farmer's attitude (see below), a relation that had already been obtained using more sophisticated measurements [START_REF] Breuer | Behavioural response to humans and the productivity of commercial dairy cows[END_REF][START_REF] Waiblinger | The relationship between attitudes, personal characteristics and behaviour of stock-people and subsequent behaviour and production of dairy cows[END_REF].

On 54% of farms, less than 10% of cows could be touched, and the median percentage of cows that accepted being touched reached 9.10%. This result raises a concern about work comfort and efficiency in dairy farms and about farmers' and animals' day-to-day safety [START_REF] Rushen | Domestic animals' fear of humans and its effect on their welfare[END_REF]. The test used in the present study reflects the "flight zone" of the cow, which varies according to its relation with humans: the smaller the flight zone, the better the human-animal relationship [START_REF] Waiblinger | Influences on the avoidance and approach behaviour of dairy cows towards humans on 35 farms[END_REF][START_REF] Grandin | How to Improve Livestock Handling and Reduce Stress. Improving Animal Welfare, A Practical Approach[END_REF]. Hence, cows accepting human contact are those with very good human-animal relationships. We found only one database and one study published using the same test on dairy farms. The proportion of cows that accepted being touched in our study (9.10%) was lower than that in the Welfare Quality database (http://www1. clermont.inra.fr/wq/), which reports a median of 30.3% of cows accepting being touched in 398 European dairy farms. It was also lower than that of [START_REF] Windschnurer | Reliability and inter-test relationship of tests for on-farm assessment of dairy cows' relationship to humans[END_REF], who reported a median of 36% in 16 Austrian commercial dairy farms. These differences may come from the small sample (16 farms) in the study of [START_REF] Windschnurer | Reliability and inter-test relationship of tests for on-farm assessment of dairy cows' relationship to humans[END_REF]vs. 118

farms in the present

Continued

probably linked to the worker/cows ratio, a factor that was kept in the final model. This suggests that the most important variable for the cow may be the variety of contacts it receives from humans. The originality of our study was thus that it took into account all the factors at the same time, and highlighted the "keystone" factors, (i.e., those most likely to be associated with the animals' response to humans).

In the multivariate model, only 7 factors, belonging to all categories except farm characteristics, were finally found to be related to cows' behavior toward humans. The variability was mostly explained by factors of calving management (39.4%; location of calving, management of the calving pen), farmer (19.7%; experience and attitude of the farmer toward cows), animals (18.8%; animal nutritional status), and worker/cow ratio (11.7%).

One of the strongest associations occurred with location and management of calving. A lower proportion of cows were touched in farms where cows calved indoors in the main pen where other cows were kept compared with farms where cows calved in a separate pen or at pasture. Experienced cows need a quiet place to calve [START_REF] Lidfors | Behaviour at calving and choice of calving place in cattle kept in different environments[END_REF][START_REF] Proudfoot | Dairy cows seek isolation at calving and when ill[END_REF]. In cattle, maternal isolation at calving and seclusion of the calf have been suggested to facilitate the establishment of the dam-calf bond because this lowers the disturbance of interactions from other cows [START_REF] Lidfors | Behaviour at calving and choice of calving place in cattle kept in different environments[END_REF]. It is also thought to lower the risk of predation on the calf. In the main pen, cows less easily find isolation from other cows or other stimuli, and may have been disturbed more at calving. Alternatively, one could hypothesize that farmers who have a deeper concern for their cows move them to a calving pen when they are indoors and about to calve, and the association with the proportion of cows touched could come from this deeper concern. However, a higher proportion of cows were touched in farms where the farmer reported not cleaning or adding litter after calving, which suggests a lower concern for cows. Surprisingly, previous results from [START_REF] Hemsworth | The effects of human presence at the time of calving of primiparous cows on their subsequent behavioural response to milking[END_REF]Hemsworth et al. ( , 1989b) ) showed that handling primiparous cows around calving eases their later handling during lactation. The difference between our results and those of previous studies could be partially due to the characteristics of close contacts with the person present at calving. In [START_REF] Hemsworth | The effects of human presence at the time of calving of primiparous cows on their subsequent behavioural response to milking[END_REF]Hemsworth et al. ( 1989b)), the experimenter had smeared fetal fluid from the cow's calf on his hands, the fetal fluids being an important stimulus for the dam's attraction to the calf, whereas this was not the case here. Our results suggest that calving location and management allowing separation from humans and other cows and thus probably more quietness for the cow may be beneficial to cowhuman relationships.

A higher proportion of cows were touched in farms where the farmer had more than 10 yr of experience. No previous study reports an association between farmers' number of years of experience and cattle reactions. However, we hypothesize that experienced farmers are more confident in their contacts with cows, and may be more patient with them, anticipating their reactions to adjust their behavior. We found no link between the number of years of experience the farmers had and their attitudes studied here, but we hypothesize that features such as precise quality of handling and patience toward the animals could allow smoother interactions and in turn lower fear responses of cows to humans.

Finally, our study confirms the association between farmers' behavioral attitudes and human-animal relationships. Farms where farmer had negative behavioral attitudes (reporting kicking cows, hitting them, yelling at them) had a lower proportion of cows touched, a finding already reported in dairy cows [START_REF] Breuer | Behavioural response to humans and the productivity of commercial dairy cows[END_REF] and in pigs and poultry [START_REF] Hemsworth | Human contact[END_REF]. Farmers' attitudes, farmers' behavior, and cows' reaction to human approach is a loop of association links, each item affecting the next one as well as the previous one: a cow that is frightened by people can react strongly at their approach and this in turn can reinforce a negative attitude toward that cow [START_REF] Hemsworth | Human-Livestock Interactions: The Stockperson and the Productivity and Welfare of Intensive Farmed Animals[END_REF]. According to [START_REF] Ajzen | Understanding Attitudes and Predicting Social Behaviour[END_REF], attitudes are good predictors of behavior: in the context of human-animal relationship they reflect the frequency and nature of interactions between the farmer and the animals [START_REF] Waiblinger | The relationship between attitudes, personal characteristics and behaviour of stock-people and subsequent behaviour and production of dairy cows[END_REF][START_REF] Hemsworth | Human-Livestock Interactions: The Stockperson and the Productivity and Welfare of Intensive Farmed Animals[END_REF]. Hence, our results support the fact that cow-human relationships result at least in part from the previous experience of cows in contacts with their caretakers [START_REF] Hemsworth | Human contact[END_REF].

An important factor associated with animal responses to humans was the proportion of very lean cows. When this proportion was high, cows could be more easily touched. Body condition reflects the nutritional status of an animal. In Welfare Quality, "very lean" corresponds to a score of <2.5 in the grid of Edmonson et al. (1989), meaning that energy needs are not met by the dietary supply. The avoidance distance test was performed just after morning milking, when cows were highly motivated to eat. Although, the approach text at the feeding rack is correlated with a similar test performed in the pen (that is, when the cow is not feeding; [START_REF] Windschnurer | Reliability and inter-test relationship of tests for on-farm assessment of dairy cows' relationship to humans[END_REF], we could hypothesize that cows with a very low body condition are more motivated to consume feed than to recoil from the experimenter.

The ratio of persons working with cows per lactating cow was more closely associated with the proportion of cows touched than the attitudes of the main caretaker: the higher the ratio, the more cows could be touched. This factor in dairy cows' response to humans had not yet been reported. [START_REF] Lensink | The farmers' influence on calves' behaviour, health and production of a veal unit[END_REF] observed a lower withdrawal tendency of veal calves (to the passage of an unfamiliar observer and the farmer) when a high number of caretakers worked at the veal unit. This effect could be due to cows being more accustomed to interacting with different people, with a different appearances and gestures, so that through the process of stimulus generalization [START_REF] Hemsworth | Human-Livestock Interactions: The Stockperson and the Productivity and Welfare of Intensive Farmed Animals[END_REF], they were less afraid of the experimenter approaching them during the test.

Several factors were expected to be associated with cows' reaction in the test, but were not evidenced by our multivariate model. For instance, handling facilities are of importance for interventions on cattle to lower cattle stress during handling, and promote human safety [START_REF] Grandin | How to Improve Livestock Handling and Reduce Stress. Improving Animal Welfare, A Practical Approach[END_REF]. The lack of any links between handling facilities and cows' avoidance reaction may be explained by the narrow variation between farms from our sample in handling facilities used for several interventions on dairy cows. Regarding genetic factors, our study provides no evidence of any differences in the human-animal relationships among dairy breeds, as already suggested [START_REF] Waiblinger | Influences on the avoidance and approach behaviour of dairy cows towards humans on 35 farms[END_REF][START_REF] Haskell | Genetic selection for temperament traits in dairy and beef cattle[END_REF]. This low variability may be because both Holstein and Montbeliarde are dairy breeds: such cows come into contact with humans twice daily for milking. Besides production level traits, their selection might therefore have included behavioral traits such as temperament to ensure handling efficiency and human safety [START_REF] Haskell | Genetic selection for temperament traits in dairy and beef cattle[END_REF].

The final model explained only 32.7% of the variability between farms. This moderate proportion could be explained by potential factors not analyzed in our study. For instance, we did not include factors related to adverse events, such as the frequency of veterinary interventions, which may result in higher avoidance reactions [START_REF] Waiblinger | Previous handling and gentle interactions affect behaviour and heart rate of dairy cows during a veterinary procedure[END_REF], nor did we ask farmers if cows' temperament was of importance for the selection of the herd. Another hypothesis is the presence of strong individual differences between cows and between herds, due to variable genetic background or early experience in life.

In conclusion, our study suggests that variations in cow-human relationships are essentially associated with management and the farmer. The housing and milking systems were not found to be associated with this relationship. Our study confirms that variety in human contacts is associated with a lower proportion of fearful cows, and that negative attitudes of caretakers toward cows is associated with higher proportion of cows being afraid of humans; nevertheless, behavioral attitudes did not explain most of the variability between farms. Our study highlights an association between place at calving (isolation from other cows and humans) and humananimal relationships. Nevertheless, the cross-cutting epidemiological approach used in this study does not let us make conclusions on cause-effect relations, but helps to formulate new hypotheses to test in intervention studies or in controlled experiments. Experiments to assess how cows perceive and react to human presence at calving would give insights into their motivation for isolation from humans, and into the short-, middle-, and long-term effects of human presence at calving on cow-human relationships. Similarly, the measure of cows' motivation to feed according to their body condition could be checked in experimental conditions, as already done to study cows' motivation to feed according to milk production [START_REF] Cooper | The motivation of high-and low-yielding dairy cows to obtain supplementary concentrate feed[END_REF]. The sample of farms was chosen to reflect the diversity of loose-housing dairy farms in France in terms of herd size, breed, location, and so on [START_REF] Agreste | Enquête bâtiments d'élevage bovins, Principaux résultats sur les exploitations, l'utilisation des déjections, les équipements, les bâtiments fosses et aires[END_REF][START_REF] Livestock | Dairy production in 2015 in France, to an accentuation of regional contrasts[END_REF]. Further studies in large farms with several groups of cows being managed in parallel by different caretakers could bring additional information on the specific contribution of caretakers on human-animal relationships while the environment remains similar for all cow groups. We did not include tied-stall systems because these are less frequent in France [START_REF] Livestock | Dairy production in 2015 in France, to an accentuation of regional contrasts[END_REF]. Further studies that include tied-stall systems are needed, especially in countries where they are still common.

  relationships = human-animal relationships.

Figure 1 .

 1 Figure 1. Distribution of the proportion of cows touched during the avoidance distance test in 118 dairy farms.

Table 1 .

 1 Factors studied: categories, factors, and levels

	Category and factor

1 < 6,000; 6,000 ≤ Q < 8,000; 8,000 ≤ Q < 10,035 Other livestock production on the farm No. of people working with cows/lactating cow (worker/cow ratio) Ratio <0.05; ratio ≥0.05 Daily time: feeding/lactating cow (min) <1 min; ≥ 1 min Daily time: milking/lactating cow (min) <3 min; ≥ 3 min; AMS Daily time: barn cleaning/lactating cow (min) Time <1 min; time ≥1 min Daily time: total/lactating cow (min) Time <5 min; 5 min ≤ time < 10 min; time ≥10 min Interventions on animals Dehorning practices Farmer: disbudding; farmer: dehorning; veterinarian Main facility used for neck intervention Pen; feed barrier; no particular facilities Blocking cows after morning milking Yes; no Barn work Litter provision/cow per day ≥Recommendations; <recommendations Corridor scraping: method used Manual or/and tractor; automatic or duckboard Corridor scraping: frequency 1 or 2/d; >2/d; <1/d; automatic or duckboard Reproduction Main facility used for artificial insemination Feed barrier; pen; no particular facilities Bulls choice for heifer based on calving ease Yes; no Main calving location Isolated in a calving pen; with herd in barn; with herd at pasture Cleaning or adding litter after calving Yes; no Main facility used for intervention at calving Pen; feed barrier; no particular facilities; no intervention Hoof trimming Presence of hoof disinfection facilities Yes; no Main facility used for hoof trimming Restraining cage; no particular facility; no hoof trimming Performer of preventive hoof trimming Farmer; professional trimmer; other person Proportion of cows with preventive hoof trimming All cows in herd; some of the cows; no preventive trimming Animal No. of displacements/cow per hour <1 displacement/cow per hour: ≥1 displacement/cow per hour Proportion of primiparous cows in herd <30%; ≥30% Proportion of Holstein cows in herd ≥50%; <50% Proportion of cows with mastitis in herd ≤10%; 10% < cows ≤ 20%; 20% < cows ≤ 30%; >30% Average month of lactation 4; 5; 6; 7; 8; 9 Percentage of very lean cows in herd <15%; 15% < cows ≤ 30%; 30% < cows ≤ 45%; >45% Percentage of lame cows in herd 0% ≤ cows ≤ 15%; 15% < cows ≤ 35%; 35% < cows Farmer Years of experience (exp.) <10 yr; 10 yr ≤ exp. < 20 yr; 20 yr ≤ exp. < 30 yr; 30 yr ≤ exp. Main milker's gender Male; female Most important issue for farm success Technical skill; H-A relationships 2 ; ambiance; genetics; health 1 Q = quota.

Table 2 .

 2 Principal component analyses (PCA) on attitudes of farmers: PCA on job satisfaction, PCA on cognitive attitudes, and PCA on behavioral attitudes: for each principal component considered we give the eigenvalue, proportion of variance explained by the component, and contribution of each variable to the component 1

	PCA

Table 3 .

 3 Coefficients of univariate Poisson regression models (Z-value and P-value are stated for Wald tests of contrasts between modality "ref" and other ones) between farm/animal/management/farmer variables and the prevalence of cows touched on a farm adjusted for sample size

				% of cows
				touched
	Category and factor	Level	No. of farms	predicted by model 1	95% CI	Z	P-value
	Farm
	Milking system	Milking parlor (ref)	100	10.3	[9.31-11.3]
		AMS	18	13.3	[10.9-16.2]	2.27	0.023
	Quotas (L)/year per lactating cow	3,000 < P < 6,000 (ref)	20	8.13	[6.16-10.4]
		6,000 ≤ P < 8,000	70	11.2	[10.0-12.5]	2.21	0.027
		8,000 ≤ P < 10,035	25	11.8	[9.77-14.2]	2.29	0.022
	Other livestock production on the farm	Yes (ref)	63	9.60	[8.43-10.9]
		No	55	12.2	[10.7-13.9]	2.66	0.007
	Animal No. of displacements/cow per hour 2	≥1 displacement/cow per hour	86	10.0	[8.94-11.2]
		(ref)
	Proportion of cows with mastitis in herd 2	<1 displacement/cow per hour 10% < cows ≤ 20% (ref)	32 42	12.8 9.01	[10.9-14.9] [7.61-10.6]	2.55	0.011
		≤10% of cows	16	11.2	[8.78-14.1]	1.50	0.135
		>30% of cows	20	11.4	[9.13-14.0]	1.71	0.087
		20% < cows ≤ 30% of cows	40	12.9	[10.6-14.2]	2.78	0.005
	Average month of lactation	5 (ref)	37	9.54	[8.00-11.2]
		≥7	18	10.5	[8.28-13.2]	0.68	0.495
		6	44	11.2	[9.61-12.9]	1.38	0.167
	Percentage of very lean cows in herd 2	4 45% ≥ cows > 30% (ref)	18 9	13.3 7.55	[10.7-16.4] [5.01-10.8]	2.39	0.016
		15% > cows	71	9.59	[8.45-10.8]	1.16	0.247
		30% > cows > 15%	22	12.8	[10.6-15.4]	2.43	0.015
	Percentage of lame cows in herd 2	cows >45% 15% > cows > 0% (ref)	16 76	14.8 10.0	[12.0-17.9] [8.89-11.2]	3.04	0.002
		35% > cows > 15%	31	12.0	[10.1-14.1]	1.75	0.079
		cows >35%	11	12.8	[9.68-16.4]	1.64	0.101
	Management
	No. of people working with cows	2 persons (ref)	67	10.4	[9.25-11.8]
		1 person	27	10.5	[8.61-12.8]	0.76	0.939
		3 persons	20	10.5	[8.36-12.9]	0.01	0.989
		4 persons	4	19.5	[13.5-27.1]	3.33	0.001
	No. of people working with cows/lactating	Ratio <0.05 (ref)	89	9.76	[8.75-10.9]
	cow
	(worker/cow ratio)	Ratio ≥0.05	29	14.2	[12.0-16.6]	3.78 <0.001
	Daily time: milking/lactating cow (min)	<3 min (ref)	28	7.74	[6.19-9.54]
		≥3 min	72	11.35	[10.1-12.7]	3.07	0.002
		AMS	18	13.4	[10.9-16.2]	3.64	0.003
	Main calving location	Cow with herd, in the barn (ref)	15	7.10	[5.10-9.58]
		Cow with herd, at pasture	49	10.5	[9.07-12.1]	2.22	0.027
		Cow isolated in a calving pen	52	12.4	[10.9-13.9]	1.75 <0.001
	Cleaning or adding litter after calving	Yes (ref)	79	9.23	[8.18-10.4]
		No	39	14.0	[12.2-15.9]	4.49 <0.001
	Presence of hoof disinfection facilities	Yes (ref)	38	9.26	[7.80-10.9]
		No	80	11.6	[10.4-12.9]	2.27	0.024
	Farmer
	Years of experience (exp.)	<10 yr	21	7.35	[5.59-9.28]
		20 yr ≤ exp. < 30 yr	41	10.1	[8.61-11.9]	2.17	0.029
		10 yr ≤ exp. < 20 yr	38	12.2	[10.5-14.1]	3.46 <0.001
		30 yr ≤ exp.	18	13.6	[11.0-16.6]	3.77 <0.001
	Main milker's gender	Male (ref)	107	10.4	[9.4-11.4]
		Female	11	14.6	[11.3-18.3]	2.53	0.0114
	Issue identified as most important for	Farmer's technical skill (ref)	74	9.83	[8.67-11.0]
	farm success	Genetics	11	10.8	[7.85-14.5]	0.61	0.543
		Ambiance in the barn	10	11.7	[8.55-15.6]	1.09	0.275
		Human-cow relationship	13	12.7	[9.89-16.1]	1.91	0.056
	PCA 3 "job satisfaction": Component 1	Health Intercept	9	13.8 10.8	[10.3-18.1] [9.87-11.8]	2.21	0.028
		Component 1		+1.07		2.38	0.017
	PCA "job satisfaction": Component 2	Intercept		10.7	[9.80-11.8]
		Component 2		+1.11		2.69	0.007

Journal of Dairy Science Vol. 99 No. 7, 2016

Bold represents variables that contribute most to the component.

Journal of Dairy Science Vol. 99 No. 7, 2016 EPIDEMIOLOGICAL SURVEY ON COWS-HUMAN RELATIONSHIPS

ACKNOWLEDGMENTS

We thank the Groupements de Défense Sanitaire for lists of eligible farms, all the farmers who freely cooperated in this survey, and Danone Research for financial support. We are also particularly grateful to Maud Coignard (ONIRIS, Ecole Nationale Vétérinaire Agroalimentaire et de l'Alimentation Nantes-Atlantique, Nantes, France), Eric Delval and Christophe Mallet (INRA, Institut National de la Recherche Agronomique, Saint-Genès-Champanelle, France), and Remi Debauchez (ISARA, Institut Supérieur d'Agriculture et d'agroalimentaire Rhône-Alpes, Lyon, France) for their help in data collection; Jean-Yves Audiart and Didier Billon (ONIRIS, Nantes, France) for their help with data entry; and Julie Cat and Céline Faverjon (INRA, Saint-Genès-Champanelle, France) for their advice on statistics. The authors also thank Joop Lensink (ISA, Institut d'enseignement Supérieur spécialisé en Agriculture, Lille, France) for valuable advice on questionnaire design. We also thank ATT (Clermont-Ferrand, France) for language editing.

EPIDEMIOLOGICAL SURVEY ON COWS-HUMAN RELATIONSHIPS 9 study) or from differences in farmers' practices, in the animals themselves, or in farm variables. Our study can help gain a better understanding of such variations.

When considered separately (i.e., in univariate models), factors from all the categories studied [animals (behavior, health, breed, rank of lactation), farm characteristics, farm management, farmers' attitudes] were significantly associated with the proportion of cows touched when approached at the feeding rack. Not all of these factors were kept in the final multivariate model: the information they carried was summarized by factors kept in the final model, owing to confounding effects. For instance, the daily time spent milking cows and the number of people working with cows were Example: compared with reference (1.81% of cows touched) if the "percentage of very lean cows in herd" is not "30% < cows ≤45%" (ref) but "<15%," then the percentage of cows touched is multiplied by 1.30: it reaches 2.34%. 1 Example: if the "milking system" is not "milking parlor" (ref) but automatic milking system (AMS), then the percentage of cows touched reaches 13.3%; compared with reference (10.3%), it increased 3%.

2 Measure of the Welfare Quality protocol.

3 PCA = principal component analysis.