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BACKGROUND: Consumers, the industry, and many farmers have shown increased interest in alternative management systems that allow for cow-calf contact (CCC) and this topic has become an important focus of research for a sustainable dairy industry. Among the many knowledge gaps still existing in this novel research field, there is a need for further research to investigate effects of CCC beyond the nursing period (i.e., after cow-calf separation). Moreover, multi-herd observational studies are scarce. Therefore, the aim of this study was to investigate the within-herd effect of CCC on machine milk yield and calf growth beyond separation. In this prospective cohort study, we studied all cows and their calves (Norwegian Red breed) born between September 1st 2021 and January 31th 2022 at three Norwegian dairy farms, investigating the impact of CCC on machine milk yield and calf average daily gain (ADG) after separation of the cow-calf pair. The follow-up period was 305 d for cows and six months for calves. Machine milk yield was automatically registered at each milking and calf heart girth was measured once a month. As various contact durations emerged, they were categorized into three groups: no contact (NC 0-3 d), short duration (4-30 d) and long duration (> 30 d). Data were analyzed with linear mixed models with the individual animal as the unit of interest. For cows, days in milk (DIM) from date of separation up to 305 DIM were included in the analysis as a continuous variable. For calves, age up to 195 d was used in the statistical analysis. RESULTS: We found no differences in machine milk yield after separation across the different contact groups: cows with no contact (n = 28), short duration (n = 51) and long duration (n = 27) of contact, all exhibited comparable milk yields from the time of separation until the end of lactation. Furthermore, in the case of calves, no disparities in average daily gain (ADG) were identified for any of the contact groups: calves with no contact (n = 39), short duration (n = 61) and long duration (n = 38) of contact, displayed comparable growth during the first six months of life. CONCLUSIONS: Our findings indicate no negative effects of CCC on machine milk yield after separation, nor any sustained effects on calf growth under the conditions of this study. More multi-herd observational studies conducted on-farm is needed to expand the understanding of effects of CCC on cow and calf performance after separation.

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Knowledge is lacking on separation strategies that can best prepare calves to final separation from the dam in cow-calf contact (CCC) systems. This controlled trial compared the effects of 2 different methods to gradually reduce cows' access to their calf termed "debonding" on calf growth in a cow-driven CCC system. Initially, cows (Norwegian Red breed) had 24 h/d computer-controlled access to their calves. In the long debonding (LDB) treatment (n = 16), a gradual reduction of cows' access to their calves was initiated 28 d after calving over a total duration of 28 d; first to 12 h/d (14 d), and then to 6 h/d (14 d). In the short debonding (SDB) treatment (n = 14), reduction was initiated 45 d after calving over a total duration of 10 d; first to 12 h/d (5 d), and then to 6 h/d (5 d). From 6 h/d, access was finally reduced to 0 h/d for 4 d for both treatments, resulting in a study period of 60 d in total. Calves had ad libitum access to concentrate, hay and water throughout the study. Independent of treatment, ad libitum access to whole milk from an automatic feeder was granted once cow access was reduced. Cows and calves had the possibility for fence line contact at all times. The primary outcome variable calf weight gain was registered biweekly. Calf ADG was analyzed with a linear mixed model. The ADG was similar across treatments during 24 h/d access (1.04 ± 0.07 kg). Debonding treatment affected calf growth differently with each gradual reduction in cow access (12 h/d, 6 h/d and 0 h/d); however, no main effect of treatment was detected. The SDB calves had a pattern of increased ADG with the first reduction in access (+0.39 ± 0.18kg), followed by significant growth checks as access was reduced further to 6 h/d and 0 h/d (-0.41 ± 0.20 kg and -1.15 ± 0.31 kg, respectively). The LDB calves only showed significant weight checks at the final reduction in access (0 h/d access), yet at a lower degree (-0.46 ± 0.21 kg) than SDB calves. As expected, ADG was negatively associated with health events but positively associated with intake of concentrate and supplemental milk. Collectively, the results from the present study might point toward a long adaptation to separation which is initiated at a younger age being more favorable for calf performance.

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This controlled study compared the effects of 2 different gradual debonding strategies on machine milk yield, flow, and composition in a cow-driven cow-calf contact (CCC) system with automatic milking. Cows had 24 h/d access to their calves during the first weeks of lactation. In the long debonding (LDB) treatment (n = 16), a gradual reduction of cows' access to their calves was initiated 4 wk after calving over a total period of 28 d; first to 12 h/d (14 d), and then to 6 h/d (14 d). In the short debonding (SDB) treatment (n = 14), gradual reduction was initiated 6.5 wk after calving over a total period of 10 d; first to 12 h/d (5 d), and then to 6 h/d (5 d). From 6 h/d, access was finally reduced to 0 h/d for 7 d for both treatments. Machine milk yield, somatic cell count, and peak and average milk flow were automatically registered at milking. During the 9-wk study period, composite samples were analyzed for milk composition. Data were analyzed with linear mixed effect models. Results showed that machine milk yield during 24 h/d access varied between cows (range 1.2-49.9 kg/d, average ± standard deviation 13.2 ± 7.82 kg/d). The LDB cows had a higher daily machine milk yield than SDB cows at the end of and after access reduction was completed (+5.0 ± 1.63 and +5.1 ± 1.55 kg during the last 5 d of 6 h/d access, and 0 h/d access, respectively). Somatic cell count was on a healthy level, with no difference between treatments. Milk fat content increased with reduction in access, regardless of treatment. Short debonding cows tended to show higher milk protein content and lower milk lactose content than cows with a longer debonding. This study has shown that a longer debonding initiated earlier may give a higher milk yield in the short term. The variation in machine milk yield may indicate differences in milk ejection, suckling, and visiting patterns and preferences among cows.

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Dam-calf contact has been suggested to improve animal welfare in dairy calves, but practical and economical concerns have led to interest in half-day contact between cows and their calves. However, little is known about the behavioral effects of half-day contact compared with whole-day contact. The present study investigated the behavior of 45 dairy calves housed with their dams in either a whole-day system (cows only away twice daily for milking) or a half-day system (cows away from afternoon milking until after morning milking the next day). Data were video recorded during 24 h when calves were on average 3, 5, and 7 wk old. Half-day calves spent less time suckling and received less grooming compared with whole-day calves, indicating that they received less maternal care. Half-day calves were quicker to reunite with their dam when the cows returned from morning milking compared with whole-day calves. Half-day calves also suckled alien cows more often, although mainly shortly after the cows returned to the pen in the morning. This may indicate that they were hungrier than whole-day calves at this time of day. Half-day calves spent more time eating solid feeds, which may prepare them better for separation from the dam and weaning off milk. In conclusion, half-day dam-calf contact may affect calf welfare both positively and negatively, and further research focusing more directly on assessing affective states is encouraged.

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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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Most dairy farms rear calves artificially by separating the newly born calf from the dam and feeding the calf milk from a bucket. However, the general public and scientific community have begun to question the effects of artificial rearing on animal welfare. Research so far has focused mainly on dam-calf contact, where each cow takes care of her own calf. However, previous studies show that Danish and other European farmers are using and showing interest in a variety of different cow-calf contact (CCC) systems. In the present study, we used qualitative research methods to explore the perspectives of Danish farmers who either had or had tried to establish a version of a CCC system. Farmers were asked about their motivation for establishing the system, what had shaped the system to its current form, and how they perceived the calves to benefit from the system. Practical considerations was the theme most commonly brought up and related to both why farmers chose to have CCC in the first place and in what way they had chosen to organize their CCC system. Practical considerations included a sense of ease, flexibility, and a more natural and therefore rational approach. The economy was also a repeated theme, but although the economy to a large degree shapes the type of CCC chosen (dam-calf contact or foster cow contact), it was rarely mentioned in relation to choosing a CCC system in the first place. Ethical considerations were a strong motivator for farmers with dam-calf contact systems, although less so for farmers with foster cow contact. The farm's image as seen by the consumer was an important motivation for farmers with many on-farm visitors, and with the farm's image in the eyes of the farming community potentially also influencing farmers. Farmers generally perceived the calves to benefit from the care of the cow and no difference was seen in the importance attributed to care, between farmers choosing dam-calf contact and foster cow systems.

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Cow-calf contact (CCC) systems, although beneficial in many respects, introduce additional challenges to collect reliable data on milk production, which is important to assess individual cow efficiency and dairy farm profitability. Apart from weighing calves before and after each feeding, the amount of saleable milk lost due to calf suckling is practically impossible to measure. Here, we assess 2 indirect methods for estimating loss of saleable milk when housing cows and calves together in a robotic milking unit. In our study, treatment (CCC) cows and calves were kept together full time until the calves were 127 ± 6.6 d old (mean ± SD). Control cows were separated from their calves within 12 h of birth and then kept in the same unit as the treatment cows but with no access to either their own or treatment calves. Milk yield recording of both groups was performed from calving until pasture release at 233 ± 20 d in milk. The first estimation method relied on observed postseparation milk yield data, which were fed into a modified Wilmink regression model to determine the best-fitting lactation curve for the preseparation period. The second method was based on the cows' daily energy intake postseparation, calculated by measuring the daily feed intake and analyzing the energy content of the ration. The calculated energy intake was used to determine the average ratio between energy intake and the observed milk yield the following day for each individual cow, assuming constant rates of mobilization and deposition of body fat. The obtained ratio was then used to calculate the expected daily milk yield based on daily energy intake data during the preseparation period. In this paper, we analyzed data from 17 CCC cows kept together with their calves and 16 control cows; both groups calved from September to October 2020 and were followed up until release to pasture in May 2021. Saleable milk yield was lower in CCC cows than in control cows, both before and after separation. The 2 methods were used on data for control cows and showed milk yield loss using the lactation curve method (average of -3.4 ± 2.8 kg/d) and almost no loss using energy intake data (average of -1.4 ± 2.7 kg/d). Milk yield loss for CCC cows was estimated at average 11.3 ± 4.8 and 7.3 ± 6.6 kg milk/d, respectively. The proposed lactation curve estimation method tends to overestimate milk yield loss, whereas the method based on energy intake is more accurate. However, collecting detailed energy intake data per individual cow requires additional effort and equipment, which is not always feasible on commercial farms. Further research is needed to improve milk loss estimation and to better understand trade-offs in CCC systems.

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In recent years, the common dairy farming practice of early separation of dam and calf has received increased attention. Our aim was to explore how Norwegian dairy farmers with cow-calf contact (CCC) systems apply these systems in practice, and how they experience and perceive the interrelationships between cows and calves and humans within these systems. We conducted in-depth interviews with 17 farmers from 12 dairy farms and analyzed responses inductively, inspired by the grounded theory approach. The farmers in our study practiced their CCC systems differently from each other and had varying as well as common perceptions about these systems. Calves' intake of colostrum was not seen as a challenge, regardless of practice. The farmers generally perceived that any aggression shown by cows toward humans was merely an exhibition of cows' natural protective instinct. However, when the farmers had good relationships with their cows and the cows felt safe around them, the farmers could handle the calves and build good relationships with them as well. The farmers experienced the calves learning a lot from their dams. Most of the farmers' dairy housing systems were not adapted for CCC, and CCC systems could require modification in terms of placing greater emphasis on observing the animals and making adjustments in the barn and around milking. Some thought having CCC on pasture was the best and most natural, while others were reluctant to have CCC on pasture. The farmers encountered some challenges with stressed animals after later separation, but several had found methods to minimize stress. Generally, they had different opinions about workload, but agreed they spent less time on calf feeding. We found that these farmers were thriving with their CCC systems; they all described positive emotions around seeing cows and their calves together. Animal welfare and natural behavior were important to the farmers.

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We investigated whether different rearing conditions affected the physical development, ease of integration into the dairy herd and performance of primiparous dairy cows and the results are reported in this Research Communication. The three rearing conditions investigated were whole-day cow-calf contact for 9 weeks (WDC), half-day contact for nine weeks (HDC) and no mother-contact (NC) with nipple-bucket-feeding (max. 2 × 3 l/d) and group-housing from the 8th day onward. After permanent separation from the dams (WDC and HDC), all calves had been nipple-bucket-fed and gradually weaned from week 10 to 13 of life and kept together as calves and heifers. Measures of physical development were trunk girth, height at withers and body weight. Lying behavior during the first 48 h after introduction to the dairy herd after first calving was used as an indicator of ease of integration. Performance measures were age at calving, lactation duration, milk yield and culling rates during the first lactation. No differences between WDC and HDC could be detected. Moreover, no treatment-effects on physical development or performance could be found. All treatments showed reduced lying for the first 24 h after introduction to the dairy herd. Afterward NC-heifers lay less than WDC, with HDC-heifers ranging in between. We conclude that under the conditions investigated higher weights two weeks after weaning in WDC- and HDC-calves did not carry through to the first lactation and did not lead to earlier maturity and higher performance, but that integration into the herd may be alleviated when calves have early experience of the herd and associated conditions.

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Due to increasing public concern regarding separation of the dairy cow and calf within the first days after birth, alternative systems, where cows and calves stay in contact for an extended period, are receiving increasing interest from a broad array of researchers and other stakeholders. With more research in the area, there is a risk of inconsistencies emerging in the use of terminology. To create a better consensus in further discussions, the aim of this Research Reflection is to provide definitions and propose a common terminology for cow-calf contact in dairy production. We also suggest definitions for various systems allowing cow-calf contact and describe the distinct phases of cow-calf contact systems.

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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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BACKGROUND: For suckling dairy calves, different management routines to ensure sufficient colostrum intake are applied: visual assessment, hand feeding supplemental colostrum or assistance. However, knowledge on the efficacy of these methods to prevent failure of passive transfer [FPT: serum immunoglobulin (IgG) < 10 g/L] is lacking. Our objectives were to explore FPT prevalence in suckling dairy calves and associations with common management routines to ensure colostrum intake. From 20 organic herds, 156 calf blood samples (mean ± SD; 7.8 ± 1.24 per herd) and 141 colostrum samples from the dams were analysed. All calves suckled the dam. Factors known to affect serum and colostrum IgG were evaluated, including the method applied by the producer to ensure calf colostrum intake and whether it deviated from routine practice for any reason. RESULTS: The prevalence of FPT was 31%. Mean serum and colostrum IgG (± SD) were 16.0 ± 10.0 g/L and 39.4 ± 26.4 g/L, respectively. Only colostrum IgG was found to have a statistically significant influence on the prevalence of FPT. Variation in serum IgG was also explained mainly by colostrum IgG. Of calves receiving colostrum according to farm routine, calves receiving supplemental colostrum with a bottle had lower serum IgG levels than did calves receiving no additional colostrum. However, no within-herd effect was found. With a high between-herd variation, colostrum IgG ranged from 2 to 135 g/L, and only 23% of the samples had a IgG content > 50 g/L. Colostrum IgG was significantly higher in samples collected during spring, compared to samples collected during winter, and lower in 2nd parity cows. CONCLUSIONS: The results indicate that for calves capable of finding the udder and suckling independently, there is no direct benefit of routinely hand feeding colostrum although herd level factors (e.g. feeding, management etc.) may play an important role. FPT prevalence in this study was high, and comparable to that of calves in conventional herds, separating cow and calf at birth. Still, the findings of a high FPT prevalence and inferior colostrum quality indicates a need for improved awareness among dairy producers practicing cow-calf suckling.

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Dam rearing can provide health and welfare benefits, but separation and weaning are major welfare challenges. We investigated whether access to an additional source of milk from an automatic milk feeder (AMF) would improve weight gains after separation and weaning. During the first 6wk of life (dam phase), calves were assigned to 1 of 3 treatments using a parallel group design with repeated measures: nursing (n=10) and combined (n=10) calves could suckle from their dams at night (between 2000 and 0800h), and combined calves also had access to 12 L of milk/d accessible 24h/d from an AMF. Milk feeder calves (n=10) also had access to an AMF 24h/d and were housed with the dam at night but were prevented from suckling by an udder net. Separation from the dam occurred after 6wk in 2 phases with decreasing contact between cow and calf: partial separation (duration 4d) and total separation (duration 3d). At separation, all calves were granted access to 12 L of milk 24h/d from the AMF until weaning began at 7wk of age. We hypothesized that access to an AMF during the dam phase would result in less weight loss at separation and weaning compared with calves that had been nutritionally dependent upon the cow (i.e., nursing calves). Calf weight gain during the dam phase averaged (±SD) 1.1±0.26kg/d and did not vary with treatment. Combined calves drank less milk from the AMF compared with milk feeder calves during the dam phase (mean ± SEM daily milk intake: 1.1±0.38 vs. 8.2±0.34 L/d) and tended to drink less during partial separation (6.7±1.28 vs. 9.8±1.02 L/d), but milk intake from the AMF did not differ between these treatments in the later phases. During the same phases, nursing calves consumed less milk from the AMF than the other treatments; of the 10 calves, 6 did not use the AMF (consuming <1.5 L/d) after the dam phase. After separation, nursing calves gained less weight than calves in both the milk feeder and combined treatments (0.8±0.16 vs. 1.2±0.08kg/d). Calves using the AMF after separation (n=23; 4 nursing calves, 9 combined calves, and 10 milk feeder calves) had a higher average daily gain compared with calves that did not (n=7; 6 nursing calves and 1 combined calf; 1.2±0.07 vs. 0.6±0.21kg, respectively). In conclusion, use of the AMF after separation varied, but providing an additional milk source reduced nutritional dependency on the dam, improving calf performance at weaning and separation.

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