Bovine mastitis is one of the most common diseases in the dairy industry and it is a major welfare problem. Pain during mastitis is generally assessed through behavior but a combination of indicators would increase the chances of detecting pain and assessing its intensity. The aim of this study was to assess behavioral and patho-physiological responses as possible signs of pain experienced by cows after experimental intramammary challenge (mastitis) with Escherichia coli. Six Holstein-Friesian cows received an inoculation of E. coli P4 in one healthy quarter. Evolution of the disease was assessed using bacteriological growth and somatic cell counts (SCC). Cows' response to the challenge was monitored by direct behavioral and clinical observations, data loggers, rumen temperature sensors, and indicators of inflammation, stress, and oxidative status. From all data recorded, the variables that contributed most to the discrimination of mastitis phases were obtained by factorial discriminant analysis. Baseline levels of all indicators corresponded to values before challenge. Specifically, we weighted data relating to lying behavior by the observations at the same hour of the day before challenge to eliminate the circadian rhythm effect. We identified 3 phases that were discriminated by factorial discriminant analysis with good performance. Nine indicators varied according to the phase of the disease: cows' attitude toward their surroundings, tail position, clinical signs, ear position, variation of postural changes, concentrations of haptoglobin and serum amyloid A (SAA), cortisol blood levels, and rumen temperature (as a surrogate for body temperature). In phase 1 (4 to 8 h postinoculation), E. coli proliferated exponentially in milk but inflammation indicators remained at baseline levels. Cows were less attentive toward their surroundings (median score, 0.63), and postural changes (lying/standing) were less frequent (0.75 times from baseline). In phase 2 (12 to 24 h postinoculation), bacterial concentrations peaked around 12 h and then began to decrease concomitantly with a sharp SCC increase. Cows were less attentive toward their surroundings (score, 0.54), had high plasma cortisol (31.3 ng/mL) and SAA (100.3 µg/mL) concentrations, and rumen temperature was increased (40.3°C). In phase 3 (32 to 80 h postinoculation), bacterial concentrations decreased concomitantly with high SCC levels. Cows had high levels of haptoglobin (0.57 mg/mL) and SAA (269 µg/mL) but showed no behavioral changes. Dairy cows displayed changes of behavioral, inflammatory, and stress parameters after E. coli mammary inoculation. Our results suggest that cows may have experienced discomfort in the preclinical phase (phase 1) and pain in the acute phase (phase 2) but neither discomfort nor pain in the remission phase (phase 3). Although larger controlled studies are needed to confirm our findings, this knowledge could be useful for early detection of E. coli mastitis and for decision-making regarding the initiation of pain-relief treatment during mastitis in dairy cows. This would improve animal welfare and potentially faster disease remission.

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 important 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.

Adults play an important role in regulating the social behaviour of young individuals. However, a few pioneer studies suggest that, more than the mere presence of adults, their proportions in social groups affect the social development of young. Here, we hypothesized that aggression rates and social cohesion were correlated to adult-young ratios. Our biological model was naturally-formed groups of Przewalski horses, Equus f. przewalskii, varying in composition. We investigated the social interactions and spatial relationships of 12 one- and two-year-old Przewalski horses belonging to five families with adult-young ratios (AYR) ranging from 0.67 to 1.33. We found striking variations of aggression rates and spatial relationships related to the adult-young ratio: the lower this ratio, the more the young were aggressive, the more young and adults segregated and the tighter the young bonded to other young. This is the first study demonstrating a correlation between adult-young ratios and aggression rates and social cohesion of young individuals in a naturalistic setting. The increase of aggression and the emergence of social segregation in groups with lower proportions of adults could reflect a related decrease of the influence of adults as regulators of the behaviour of young. This social regulation has both theoretical and practical implications for understanding the modalities of the influence of adults during ontogeny and for recommending optimal settings, as for instance, for schooling or animal group management.