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Cow-calf systems represent a significant research area in animal husbandry, with differences depending on the final product (meat or milk). This study aimed to apply text mining and topic analysis on literature describing cow-calf systems in European, American, and Brazilian beef and dairy sectors between 1998 and 2023. Additionally, cow-calf contact (CCC) literature data was manually extracted. Our findings revealed the presence of 11 research areas among literature on cow-calf systems, with different priorities identified in the beef and dairy sectors. Beef industry mainly focused on animal proficiency and nutrition, while dairy on animal welfare and CCC, which showed a growing trend as emerging research topic, mostly in the EU. Current debates around calf welfare and EU's planned animal welfare legislation revision appeared to be driving the increasing interest in this topic. Studies in the beef sector were mainly localized in Brazil, showing that research in different contexts and species is important for CCC implementation. Manual data extraction showed considerable variation in the retained CCC documents regarding sample size, type of contact, methods and CCC duration. Learning about the varied CCC approaches used in beef and dairy farms in different locations, concentrating on their strengths and weaknesses, will help to develop novel solutions to global challenges. Adopting validated and robust indicators would help scientists and policymakers to monitor the system's quality. To improve CCC feasibility, match consumer demands, and move towards One Welfare and One Health, future research should focus on a variety of situations to overcome the current shortcomings.

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Cow-calf contact (CCC) rearing is becoming an increasingly popular alternative to the common practice of early separation of cow and calf in dairy management. Milkability can be impaired in nursing cows, which contributes to the loss of machine milk yield caused by calf intake, especially in pure dam-calf contact (DCC) systems. The aims of this study were (1) to describe the current status quo of DCC rearing regarding management and milking and (2) to evaluate the effects of DCC (suckling and milking vs. milking alone) and the effects of different types of DCC on milkability parameters, teat condition, and behavior during milking on Swiss DCC farms. By means of 17 telephone interviews with DCC farmers, we collected data on DCC management, housing, separation and weaning processes, milking procedures and techniques, and perceived milkability problems. Subsequently, we collected data on 10 of the interviewed DCC farms (183 cows): 4 DCC farms with a whole-day contact (WDC) system, 3 farms with DCC before milking (CBM), and 3 farms with DCC after milking (CAM). Five farms on which calves had no contact with dams were chosen as reference farms (178 cows). Using a milk flow meter, the occurrence of ejection disorders, bimodality of the milk flow curve, machine milk yield, duration of the decline phase, and duration of prestimulation were measured. The average mouthpiece chamber vacuum during the main milking phase and hind leg activity during milking were measured using a pressure sensor and an accelerometer, respectively. After cluster removal, the teat condition was evaluated, and a stripping milk sample was taken for fat content analysis. The interview results revealed that 8 of the 17 farms surveyed had a WDC system, and 2 farms operated a daytime DCC system. Contact before milking was applied by 3 farms, and 3 farms allowed CAM. On one farm, calves had access to dams 3 times a day. A great diversity in cow-calf management was found. In the on-farm data collection, 20 milkings of a total of 701 milkings examined met the criteria for a clear ejection disorder, with 17 of these observations occurring on WDC farms and none on reference farms. The stripping milk fat content was lower in nursing cows, indicating a lower degree of udder emptying. Machine milk yield was higher in nursing CAM cows than in nursing WDC and CBM cows. Farm types did not differ regarding teat condition, hind leg activity, or the occurrence of bimodal milk flow curves. In conclusion, the large variation in individual management approaches to DCC rearing even within DCC types, such as calf housing or cow breeds, implies caution when interpreting results. Contact after milking may be the system most beneficial for some productivity parameters, but adequate calf supply must be ensured. Higher amounts of milk remaining in the udder after cluster removal indicate that nursing can affect milkability, but future research should consider the effects of udder filling before milking to better interpret the fat content of stripping milk.

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Cow-calf contact has been suggested as an alternative to the common practice of early separation of dairy cow and calf. Increasing cow-calf contact poses challenges by reducing the machine milk yield and increasing separation stress. Part-time cow-calf contact may prove more feasible than full-time contact for farmers but may affect the maternal behavior of the cows. Gradually reducing the daily contact could gradually wean the calf off milk, preparing it for separation. This study aims to investigate (1) how cows' maternal behaviors toward their own calf are affected by part-time contact, and (2) whether calves' suckling behavior is reduced by reducing daily cow contact. Fifty-six dairy cows and their calves were assigned to either full-time (23 h/d) or part-time (10 h/d) cow-calf contact for 7 wk (main rearing period). This was followed by 2 wk of either reduced contact (50% in wk 8, then 25% of original contact time in wk 9) or unchanged contact. First, the maternal behavior of full- and part-time cows was observed for 24 h in the third week of the main rearing period. Part-time cows spent less time nursing and grooming their own calf than full-time cows did. However, the amount of nursing in the inverse parallel position and the probability of a cow nursing a calf other than her own did not differ between the 2 treatments. Second, calf suckling behavior was observed for 24 h in both weeks of the reduced contact period. Averaged across both observations, total suckling time (i.e., time spent suckling any cow) was lower in part-time calves that experienced reduced contact compared with part-time calves with unchanged contact. In wk 9, time spent suckling only the dam was lower for full-time calves with reduced contact compared with part-time calves with unchanged contact. In conclusion, although we found a lower nursing and grooming time in part-time cows compared with full-time, we found no difference between treatments with regard to nursing in the inverse parallel position and nursing a calf other than the cow's own. The effect of gradually reducing cow-calf contact on calves' suckling time requires more research.

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The weaning and separation phase remains one of the biggest challenges for cow-calf contact systems, but a gradual process that better mimics the naturally occurring reduction in milk intake has not yet been scientifically investigated. Therefore, the aim of our study was to compare behavioral and physiological indicators of distress in 3-mo-old dam-reared dairy calves (with previous full-time cow-calf contact) weaned and separated either via gradual reduction of contact time with the dam (GR; 1 wk of half-day contact, 1 wk of morning contact, and 1 wk of fence-line contact before complete separation, n = 18) or via 2-step weaning using a nose flap (NF, 2 wk of access to the dam with a nose flap, 1 wk of fence-line contact before complete separation, n = 18). Behavior was recorded 1 wk before (or for lying 3 wk before) weaning start and during the 3 wk weaning and separation period with direct observations on 4 d/wk or via accelerometers (locomotor play, lying behavior). Blood and fecal samples were taken twice per week from weaning start until 3 wk after weaning start. Calves were weighed weekly. Statistical analysis was conducted using (generalized) linear mixed models. Over the whole weaning and separation phase, NF calves showed a stronger decrease in the number of lying bouts, amount of locomotor play, and ADG, as well as a higher increase in TMR feeding time compared with GR calves, whereas GR calves vocalized more often and showed more searching behavior than NF calves. Also, the neutrophil:lymphocyte ratio of NF calves was elevated on d 3 after insertion of the nose flaps compared with baseline, but showed no change for GR calves on any sampling day. Overall, results point toward a favorable effect of a gradual weaning strategy on reduction of weaning and separation distress in dam-reared dairy calves, but the method requires further improvement from the protocol used in our study.

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In natural settings, newborn calves hide for several days before joining the herd. It is unclear whether dairy calves housed indoors would show similar hiding behaviour. This study aimed to describe the use of an artificial hide provided to calves during temporary separation from the dam and assess the effect it has on lying and sleep-like behaviour, as well as heart rate variability (HRV). Twenty-eight cow-calf pairs were randomly assigned to having a hide (n = 14), or no hide (n = 14). Hide use (n = 14), as well as lying and sleep-like behaviour (n = 28), were recorded continuously via video camera during the first hour after the dam was removed for morning milking on day three to seven. Heart rate and R-R intervals were recorded using Polar equine monitors for a subsample of 12 calves (n = 6 per treatment) on day six. Descriptive statistics were calculated for hide use. Wilcoxon Signed Rank tests were used to evaluate whether having a hide affected lying and sleep-like behaviours as well as HRV. Hide use decreased over days and was highly variable between calves. Lying behaviour did not differ between treatments. Duration of sleep-like behaviour was higher for calves without a hide compared to those with a hide. Calves with a hide tended to show signs of higher HRV and parasympathetic activity compared to calves without a hide. Results suggest that providing a hiding space to young calves may be beneficial during periods when the cow is removed from the pen for milking.

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The practice of keeping dairy cows with their calves continues to gain interest. Cow-calf contact, or lack thereof, is expected to affect emotional states, but this requires empirical testing. Different types of cow-calf contact may also affect the emotional states of cows. The primary objective of this study was to assess the emotional state of dairy cows with full-time (23 h/d), part-time (10 h/d), or no-contact with their calves (separated 48 h after birth), using a visual judgment bias test (JBT) about one month after calving; JBT is the current gold-standard method to assess emotional state in animals by evaluating optimism or pessimism (illustrated by the proverbial half-full or half-empty water glass). The secondary objective was to compare outcomes of color- versus shape-based visual JBT. Fifty dairy cows were trained to approach a positive image on a screen (rewarded with food) and to avoid a negative image (else punished with waving bag). Once learned (>80% correct over 2 consecutive days), cows were presented with 3 ambiguous images (each presented once per day among 4 positive and 3 negative images, repeated over 4 d), and their approach responses recorded. For the color method (10 full-time, 9 part-time and 11 no-contact cows), positive and negative images were a solid red or white background; ambiguous images were shades of pink. For the shape method (8 full-time, 6 part-time and 6 no-contact cows), positive and negative images were a white circle or cross on a black background; ambiguous images were overlaid circle and cross in varying shades of gray. Cows learned to discriminate colors quicker than shapes (7.3 d, confidence limits [CL]: 6.6-8.2 d; vs. 9.3 d, CL: 8.1-10.6 d). Approaches to ambiguous colors followed a generalization curve (81.0, 33.1, and 5.0 ± 3.7% for near-positive, middle, and near-negative images, respectively), but not approaches to ambiguous shapes (31.9%, 25.7%, and 21.9% ± 4.8%, respectively), indicating colors over shapes should be used in visual JBT for cattle. Part-time cows approached fewer ambiguous color images than full-time cows (23.5%, CL: 13.4%-34.4%; vs. 44.8%, CL; 32.8%-57.1%) whereas no-contact cows were intermediate, but not different from full-time or part-time cows (37.8%, CL; 26.8%-49.5%). The color JBT results show a pessimistic bias (indicating a negative emotional state) in cows with part-time calf contact, possibly due to repeated daily separation from her young calf, relative to cows with full-time calf contact. Thus, cow-calf contact systems appear to influence the emotional state of cows depending on the practice. Cows without calf contact showed no difference in judgment bias between cows with full- or part-time calf contact, suggesting these cows probably do not experience a pervasive negative emotional state (relative to those with calf contact) approximately 30 d after calf separation. However, individual variability in judgment bias was evident for all treatments. The visual judgment bias test is a useful methodology for assessing emotional states of dairy cows; future research should prioritize understanding the emotional states of dairy cows in alternative management systems.

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A positive mood in humans tends to broaden attentional scope while negative mood narrows it. A similar effect may be present in non-human animals; therefore, attentional scope may be a novel method to assess emotional states in livestock. In this proof-of-concept exploratory study, we examined the attentional scope of dairy cows housed with their calves either full-time, part-time (during daytime only), or with no calf contact (enrolled n = 10 each). Housing conditions were previously verified to induce differences in positive and negative emotional state, where part-time was considered more negative. Cows were trained to approach or avoid hierarchical images on a screen that were consistent in local and global elements (i.e., 13 small circles or crosses arranged in an overall circle or cross). After discrimination learning (>80% correct, over two consecutive days), 14 cows proceeded to test (n = 6 each full-and part-time; n = 2 no-contact, not analyzed). Test images showed inconsistent combinations of global and local elements (i.e., the overall global shape differs from the smaller local elements, such as a global circle composed of smaller local crosses and vice versa). Over two test days, approach responses to global and local images (each presented four times) were recorded. All cows were more likely to approach the local than the global image, especially part-time cows who never approached the global image; this may reflect a narrowed attentional scope in these cows. Full-time cows approached images more often than part-time cows, but overall response rates to global and local images were low, making specific conclusions regarding attentional scope difficult. Different housing conditions have potential to affect attentional scope, and possibly emotional state, of dairy cows, but statistical comparison to no-contact treatment was not possible. Cortisol concentration did not affect responses to images; thus arousal due to treatment or test conditions could not explain test performance. Further work with refined methodology and a larger sample size is required to validate the reliability of attentional scope as an assessment method of emotional state in cattle. Beyond this, the attentional scope test revealed how cattle may process, learn and respond to different visual hierarchical images, which further our understanding of cognitive and visual processes in cattle.

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This study investigated cow-calf productivity in a 10-week, pasture-based, extended suckling system featuring part-time cow-calf contact and once-a-day milking. A total of 30 dairy cows and their calves were assigned to two treatments: (1) cow and calf managed in an extended suckling system; or (2) cow and calf separated at birth and managed as usual. Cow-calf pairs grazed together during the day and spent the night separated by fence-line contact. The dams were reunited with the calves after once-a-day milking every morning. The commercial treatment pairs were separated after birth, and cows were milked twice a day and managed within the farm herd. Commercial calves were reared and managed as per commercial Australian practices. Cow-calf dams yielded 9 L/cow/day less saleable milk (p < 0.001), and their milk had lower fat (p = 0.04) but a higher protein percentage (p < 0.001) than commercial cows during pre-weaning. However, milk yield and composition were comparable post-weaning. Dam-suckled calves gained weight faster and were therefore weaned 2 weeks earlier than commercial calves, which were offered 8 L/day milk. This study has demonstrated a novel system of extended cow-calf suckling that could be practical to implement in pasture-based dairies. The long-term effects and scalability of the extended suckling system described here require further validation.

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Allowing the dam to rear her calf is an alternative practice in the dairy industry where cow and calf may gain welfare benefits from performing natural and highly motivated behaviors. However, this system has been linked to an increased separation and weaning response. Reducing the daily dam-calf contact time may be a way to prepare the calf for weaning and separation. The first aim of the present study was to investigate the effect of 8 wk of half-day dam-calf contact on calf response to weaning and separation, compared with calves reared with whole-day dam-calf contact and an artificially reared, group-housed control with unrestricted access to milk for 20 min twice daily. Weaning off milk and separation from the dam can be viewed as 2 independent stressors. By introducing each stressor separately, it may be possible to reduce the overall behavioral response. The second aim of the present study was to investigate the effect of 1-wk fence-line weaning before permanent separation. The study was conducted with a 3 × 2 factorial design with dam contact treatments (whole-day, half-day, and control) and weaning treatments (simultaneous, and stepwise). Whole-day calves were separated twice daily from their dams during milking, whereas half-day calves were separated daily from the afternoon milking and until next morning milking. Simultaneous weaning and separation were done in wk 9, and stepwise weaning and separation started in wk 8 with calves being fence-line weaned before permanent separation in wk 9. Data were collected on 69 dairy calves in wk 8 and wk 9, and data were summarized over the 2 weeks for analysis. Stepwise weaning and separation reduced the number of high-pitched vocalizations and activity of dam-reared dairy calves but had little effect on control calves. There was no difference between whole-day and half-day calves in their response to separation, but as expected, dam-reared calves reacted more strongly than the control group. This was also reflected in the average daily BW gain the week after weaning, with control calves having higher average daily gains than whole-day, while half-day calves were intermediate. However, the behavioral response did not fully wane within the observation period (0-48 h of interventions). In conclusion, 1-wk fence-line weaning reduced the summed weaning and separation response in dam-reared calves. However, no difference between half-day dam-calf contact and whole-day dam contact was detected in the behavioral response to weaning and separation.

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This Scientific Opinion addresses a European Commission request on the welfare of calves as part of the Farm to Fork strategy. EFSA was asked to provide a description of common husbandry systems and related welfare consequences, as well as measures to prevent or mitigate the hazards leading to them. In addition, recommendations on three specific issues were requested: welfare of calves reared for white veal (space, group housing, requirements of iron and fibre); risk of limited cow-calf contact; and animal-based measures (ABMs) to monitor on-farm welfare in slaughterhouses. The methodology developed by EFSA to address similar requests was followed. Fifteen highly relevant welfare consequences were identified, with respiratory disorders, inability to perform exploratory or foraging behaviour, gastroenteric disorders and group stress being the most frequent across husbandry systems. Recommendations to improve the welfare of calves include increasing space allowance, keeping calves in stable groups from an early age, ensuring good colostrum management and increasing the amounts of milk fed to dairy calves. In addition, calves should be provided with deformable lying surfaces, water via an open surface and long-cut roughage in racks. Regarding specific recommendations for veal systems, calves should be kept in small groups (2-7 animals) within the first week of life, provided with ~ 20 m2/calf and fed on average 1 kg neutral detergent fibre (NDF) per day, preferably using long-cut hay. Recommendations on cow-calf contact include keeping the calf with the dam for a minimum of 1 day post-partum. Longer contact should progressively be implemented, but research is needed to guide this implementation in practice. The ABMs body condition, carcass condemnations, abomasal lesions, lung lesions, carcass colour and bursa swelling may be collected in slaughterhouses to monitor on-farm welfare but should be complemented with behavioural ABMs collected on farm.

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In dairy systems with Zebu breeds, calves are not immediately separated from their dams after calving; consequently, maternal care and protective behavior are important, influencing both productive performance and stockpeople's safety. Our objectives were to: (1) investigate the effects of a training protocol involving pre-calving positive stimulation, delivered prior to calving, on the maternal care of primiparous Gyr cows; and (2) evaluate the effects of this training protocol on maternal protective behavior towards handlers during the first calf handling. Primiparous dairy Gyr cows (n = 37) were allocated into two groups: training (n = 16) and control (n = 21). Animal behaviors were recorded in three periods: post-calving, first calf handling, and post-handling. Maternal protective behavior during calf handling was assessed from measures of aggressiveness, attention, displacement, and agitation. Calf latency to stand up (p < 0.01) and sex (p < 0.01) differed between the training and control groups. The training group had less touching (p = 0.03), more time not interacting with the calf (p = 0.03), tended to be less protective (p = 0.056), and moved less (p < 0.01) during the first handling of their calves. In conclusion, the primiparous dairy Gyr cows subjected to pre-calving training protocol displayed less maternal care and displacement during the first handling of their calves and tended to be less protective.

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Although it is still most common to rear dairy calves separately from adult cattle, the interest in prolonged contact between dairy calves and lactating cows during early life is increasing. Previous research has documented positive effects of cow-calf contact (CCC) on for example early calf growth and udder health of suckled cows, but also negative effects such as increased separation distress and reduced weight gains after weaning. The aim of this study was to use information from European farms with prolonged cow-calf contact to identify innovative solutions to common challenges for CCC farms. Commercial dairy farms that kept calves with adult lactating cows for seven days or more after birth were invited to participate, and interviews were performed with 104 farmers from six countries. During interviews, information about farm management, calf rearing, farmers' perception of animal health on their farm, and farmers' drivers and barriers for implementing CCC were collected. We found that CCC was practised in a large variety of housing and management systems, and that calves could be reared together with their dam, with foster cows, or using a combination of the two. The contact period varied considerably (7-305 days) between farms and about 25% of the farms manually milk fed the calves during parts of the milk feeding period. Daily contact time varied between farms, from 30 minutes per day to permanent contact except at milking. Behaviours indicative of separation distress, most commonly vocalisation in cows and calves, were reported by 87% of the farmers. Strategies to alleviate separation distress, for example simultaneous gradual weaning and separation, were used on some farms. Building constraints were most often mentioned as a barrier for implementing CCC. Our findings suggest that CCC is practised in a variety of commonly used husbandry systems. Reported challenges were primarily related to weaning and separation, and to building constraints; these aspects should be areas of future research.

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Calves in most dairy farms are separated from their dams either immediately or within a few hours after birth, prompting increasing concern of the society for reasons of animal welfare. The aim of this study was to identify systems to maintain cow-calf contact (CCC) that balance the benefits for calf growth and health against the negative impacts on sellable milk and stress at weaning. We tested reuniting cows and calves for 20 min before (Before-group) or 2.5 h after (After-group) morning milking (in Trial 1) or for a 9 h period between the morning and evening milkings (Half-day-group, in Trial 2). In Control-groups, calves were separated from their dam at birth and fed with artificial nipple with tank milk provided daily at 13% (Trial 1) and 14% (Trial 2) of their BW. In both trials, each practice was applied on a group of 14 dam-calf pairs (7 Holstein [Ho] and 7 Montbéliarde [Mo]). All calves were weaned at a BW of at least 100 kg. In Trial 1, the After-group was prematurely stopped when the calves were eight weeks of age as calf growth became limited (340 g/d) due to low milk intakes (2.97 kg/d). During the first eight weeks of lactation, milk yield at the parlour was 29%, 51% and 42% lower in After-, Before- and Half-day-cows respectively compared to Controls. From week 14 to 16 when all calves were separated from their dam, Before-cows still produced 25% less milk than Control-cows while Half-day-cows reached the milk yield of Control-cows within a week. There were no significant differences in milk somatic cell count and in frequency of health disorders (cows and calves) between suckling and Control-groups. Compared to Control-calves, calf growth until weaning was higher in the suckling calves in Trial 1 (861 vs 699 g/d) and similar in Trial 2 (943 vs 929 g/d). At weaning, Before- and Half-day-calves started to vocalise earlier and continued to vocalise longer than Controls. In conclusion, the best compromise between cow milk yield and calf growth is a long period of CCC (9 h) between the morning and evening milkings. Still abrupt weaning stresses both cows and calves even if CCC has been restricted before separation.

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Under natural conditions, most parturient cows seek visual cover or seclude themselves from the herd when calving becomes imminent. Studies on calving site selection of dairy cows housed indoors show that predominantly older and dominant cows calve in secluded areas. This study aimed to investigate whether cows distance themselves further from herd members under spacious outdoor conditions and whether artificial hides on a pasture motivate cows to seek visual isolation from the herd. One hundred eighty-two Danish Holstein cows were allocated to 1 of 13 groups of 14 cows according to expected calving date. In 2 paddocks (each 75 × 150 m), 5 zones (75 m × 30 m) were defined; zone 0 contained the feeding and shade area, and zone 4 bordered an area with trees. Weekly and according to calving date, a group of 14 cows was moved either to a paddock that had 12 hides distributed evenly throughout zones 1 to 4 (7 groups) or to a paddock without hides (6 groups). The hides were wooden structures (3.3 m long × 1.0 m wide × 1.2 m high) that the cows could hide behind. One hundred seven cows calved within 14 d of having been moved to the paddock, and 82 of these (38 primiparous and 44 multiparous), and their calves, were included in the study. From 3 h before until 3 h after calving, the location, posture, and behavior of cows were recorded continuously from video recordings. In addition, location, posture, and behavior of the calves were recorded for the first 3 h after birth. Continuous variables were analyzed by linear mixed effects models, whereas binary data were analyzed using mixed effects logistic regression. The presence of hides did not affect selection of calving location in the paddock, but more primiparous than multiparous cows calved in zone 4; that is, furthest away from the feeding area. Before calving, primiparous cows were more likely to be positioned in zone 4 and less likely to approach and contact herd members. After calving, primiparous cows and their calves tended to be more likely to be positioned in zone 4. The more cows present in the paddock, the less likely the cows were to isolate (i.e., be further than 30 m away from any other cow) at the time of calving. In addition, the more cows in the paddock when a calf was born, the less time these calves spent in a lying posture. The results show that primiparous cows move further away from herd members at calving than multiparous cows and suggest that primiparous cows prefer to isolate themselves through distance rather than seeking artificial cover. Contrary to expectation, the hides did not make more cows select a calving site away from the feeding area.

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The rearing system of dairy calves with nurse cows has been developing since 2010 in organic farms in western France. This system allows cow-calf contact until a weaning age close to the natural weaning for cattle and is characterized by an early turnout for calves at around one month of age with their nurse cows and a first grazing season with mixed grazing of calves and adults at a ratio of 2-4 calves per nurse cow. The objectives of this study were to assess the gastrointestinal (GIN) and lungworm infections in such reared calves and their variability during the first grazing season. Faecal egg count (FEC), pepsinogen (PEP) concentration and Ostertagia ELISA optical density ratio (ODR) were determined in calves (n = 497) at housing in 33 groups from 24 farms in 2018, and in calves (n = 405) and nurse cows (n = 199) throughout the 2019 grazing season in 41 groups from 20 farms. For lungworm infection, information was obtained during 2019 through the recording of coughing episodes along the grazing season and the Dictyocaulus ELISA ODR determination at housing both in calves and nurses. Results indicated that the level of GIN infection was overall low for calves during the first grazing season with PEP and Ostertagia ODR group-average values ranging from 0.97 to 1.6 U Tyr and 0.23 to 0.71 ODR respectively. No anthelmintic treatment being given in any group of calves. Ostertagia ODR values increased with the duration of the grazing season (>240 d) and with the ratio calves/nurse (>2). GIN parameters for nurses remained fairly stable during the grazing season with mean FEC, PEP and Ostertagia ODR group-average values of 13 epg, 2.28 U Tyr and 0.81 ODR, respectively. Antibodies against lungworms were detected in 3-62 % of calves depending on the duration of grazing, but only 6% of calves showed a coughing episode. The dilution effect due to the mixed grazing of resistant (nurse cows) and susceptible (calves) animals associated with predominant milk diet of calves during the first months of grazing in combination with protective grazing management allow calves to be turned out at an early age without using anthelmintic treatments. Further studies are needed to assess the GIN infection dynamics during the second grazing season in weaned heifers.

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Rearing dairy calves with nurse cows has been increasingly adopted by French farmers especially in organic farming and is characterized by a fostering of two to four calves during the first month of life by an unmilked lactating cow. This type of rearing remains poorly documented regarding its impact on calf health, such as cryptosporidiosis. The objectives of our study were to describe practices related to rearing dairy calves with nurse cows and to evaluate the prevalence, intensity and risk factors for Cryptosporidium infection in calf neonates. Between January and September 2019, the rearing practices of calves were described in 20 organic French farms and faeces were sampled once from 611 animals aged between 5 and 21 days. Cryptosporidium oocyst shedding was identified by modified Ziehl-Neelsen technique and scored semi-quantitatively (score 0-4). The risk of excretion (score 0 versus 1-4) was analysed using multivariate logistic regression models. This cow-calf rearing system usually consisted of a first phase with the dam, followed by an optional phase of artificial milk feeding (calves being fed with whole milk of the farm) and a final phase of fostering by a nurse cow. Each nurse was suckled from one to five calves of close age with a fostering age of 8 days on average. The oocyst shedding prevalence was 40.2 % and similar to classically reared calves, but the intensity of shedding and the prevalence of diarrhoea appeared to be lower. The identified six risk factors for oocyst shedding were: born in the last two thirds of the birth order, born between January and July versus August and September, calf with its dam in the barn versus on pasture, having an artificial milk feeding phase versus being with the dam only, and contact between peer calves and notably the presence of an oocyst excretory calf fostered by the same nurse. These results emphasize the role of the environment for the direct and indirect contamination, particularly that related to the accumulation of oocysts from previous or peer calves facilitating the faecal-oral route of transmission. This highlights the crucial role of the premises used intensively during the winter and spring months with higher densities of calves in the barn compared to outdoor situations promoted by this rearing.

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Interest in dairy calf rearing systems with cow-calf contact during the milk feeding period is increasing among farmers, advisors and researchers, but socio-economic consequences have only scarcely been investigated yet. In this research reflection we develop a suggestion for a socio-economic methodical framework that is suitable for the wide variation of cow calf rearing systems, farm, market and societal conditions. Based on a literature based, system-theoretical structuring of involved elements, and on full cost accounting in an exemplary case study concerning two model farms, we itemize monetary factors, and additionally important non-monetary factors, that should be included in a socio-economic evaluation. This process also revealed further research needs. We propose as a next research step to gather a greater number of real farm data including different rearing systems and to perform individual full cost accountings, in order to identify input and output patterns on this basis. This might not only help to provide a robust basis for economic decision making, but also help to fill research gaps concerning long-term effects of calf rearing with cow contact. In addition, ways should be explored on how to take non-monetary effects into account.

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The study reported in this research communication aimed to assess the influence of maternal contact on calves' activity, fearfulness, and social competence. Calves were either dam-reared for their first 14 d of age (Maternal Contact, n = 12) or were separated from their dams within 12 h after birth (Motherless, n = 12). Calves of both treatments and the dams of Maternal Contact calves were group-housed and suckling was prevented with udder nets. The general activity (lying, locomotion, swapping between lying and standing) was measured using pedometers in eight Maternal Contact and eight Motherless calves within a 24-d period. Since general activity might be affected by calves' age or the separation of Maternal Contact calves from the dams the 24-d period was additionally divided into two groups (period A: 3rd-13th day of age, period B: 14th-27th day of age). Emotionality and social competence were assessed in the open field, novel object, and confrontation test with an unknown cow at 14, 21, and 28 d of age, respectively. Mann-Whitney-U-tests were performed for statistical analysis. Locomotion was greater in Motherless calves than Maternal Contact calves during the 24-d period (A + B combined, P < 0.001) and period B (14th to 27th day of age, P < 0.001). There was no treatment difference in duration of lying or in the amount of swapping in any of the periods. After a Bonferroni correction, which we used due to the exploratory character of the study, there were no treatment differences in behaviours indicating emotionality. Compared to Motherless calves, Maternal Contact calves showed increased vigilance (P < 0.01) during the confrontation test. The results of this study indicate that mother-reared calves likely searched less for social contact and developed greater social skills than calves that were separated from their mothers soon after birth.

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In this Research Reflection we describe a common standpoint on suitable methodology for controlled and observational studies in cow-calf contact systems in dairy production. Different methods to assess behaviour, health and production in cow-calf contact systems are outlined. Knowledge and experience from researchers working in this field supplement scientific literature whenever relevant. Specific methods including study design, early behaviour of cow and calf, social behaviour relevant to cow-calf contact systems, human-animal relationships and aspects related to management (milking, weaning and separation, health) are reviewed, and recommendations formed. We expect that this paper can contribute to a better understanding of the complexity of cow-calf contact systems and help to advance research in this area of dairy production.

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