About the project

The first batch of cows calved from the middle of August until the middle of September 2019 and they were kept with their calves until Christmas. In addition, twelve control cows, managed according to the standard routines in the herd, were included. The experimental cows calved outside in single pens in a mobile shed that houses four calving pens. All calvings went well, all cows had satisfactory colostrum quality and all calves suckled colostrum from their dam. Cow and calf were kept in the calving pen for the first 2-3 days post partum. The cow was fetched from the calving pen daily, to be milked in the VMS-unit. After the first few days the CowCalf pair were introduced to the group. Six CowCalf pairs moved into the VMS, and made up the "indoor group" and the remaining six pairs stayed outside until the frost came, these are referred to as the "outdoor group".

Indoor group

The indoor group had a contact area where the calves stayed at all times. Cows could access this area and in addition to meeting the calf they had access to cubicles, concentrate feeders and water in the contact area. When they wanted to eat roughage, use the comfort brush or be milked they left the contact area through a passive selection gate, which cows but not calves can open. On the way back to the calves the cows pass a selection gate that either let them straight back to the calves or directed her to milking. After passing through the milking unit she can go to the selection gate again and was then directed to the contact area. In the far end of the contact area there was a calf creep, which is an area that calves but not cows have access to. In the creep calves had cubicles and were offered hay and concentrate. There was also a scale there, for weekly body weight registrations.

Outdoor group

The contact area for the outdoor group was a pasture pen. The mobile shed used for the calvings now worked as a shelter from wind, rain and sun for cows and calves. One part of the shelter made up part of the outdoor calf creep, where calves had access to water, hay and concentrate and it was also equipped with a scale for weighing the calves. The cows could leave the contact area through a one-way selection gate (same as in the indoor set-up). Cows had access to water just outside this gate, to stimulate them to pass the gate. Once they passed the gate it seems to be easy for them to decide to go to the VMS unit, where they have access to comfort brushes, the milking unit, roughage, concentrate and other cows. Apart from the obvious difference between being indoor or outdoor the groups differ in that cows and calves outdoor can eat grass together. Research has shown that the interest in new feeds is stronger throughout life in individuals who were able to eat together with older animals in beginning of life. 

Milking

Several solutions for how to manage the cows and calves together have already been tested in this project, trying to find a solution that works well for animals and staff. It is important that cows are milked regularly and this is affected by how different resources are made available for the cows. Initially there was a large variation between cows in the frequency of visits to the milking unit. Some went several times per 24-hours while others did not go at all or did not release milk to the milking machine. When all cows had passed the first two weeks of lactation they visited the milking unit twice a day or more often. In lactation week two they gave 10-24 kg milk to the milking machine per day. It is less than the cows in the control group gave in lactation week two but this is not surprising since the cows also provide milk for their calf. The calves grew around 1.3 kg/day compared to 0.9 kg/day in the control calves.

Calm environment

The project is carried out in very close collaboration between the researchers and the barn staff. The staff have the daily supervision of the animals and notice if anything in the layout needs to be adjusted. Particular emphasis is put on handling the animals as calmly and gently as possible and to give them the chance to work things out by themselves. Time, patience and routines have been identified as important factors to make the system work. Before calving all cows in the first batch were trained daily to leave the outdoor calving area, go through the selection gate, to the VMS and through the milking unit. This was done for a couple of weeks before calvings started and the time needed for them to find the way to the milking unit decreased very quickly.

Weaning

In early lactation the cows had access to the calves day and night. When the calves were around eight weeks old the contact was restricted to half day, as a first step of the coming weaning and separation. During the half day contact period cows and calves could see each other and they were able to make contact but suckling was not possible. At around four months of age the calve and cows were moved out of the unit, to separate units. At this time calves weighed close to 200 kg and had started to show signs of puberty.

Barn design

The very first batch of the Cow and Calf Together project tested how best to incorporate a cow-calf contact (CCC) area and calf creep into an existing pen with automatic milking and freestalls. Arrows indicate the direction of cow traffic, and concentrate feeding stations are depicted with a ‘C’.

1 – Feed alley

In this part of the pen, cows had free access to silage, water and a pair of cow brushes. Silage was available in individual feed bins which facilitated the recording of feed intake for each individual cow. The only available exit from the feed alley was through an automatic selection gate (see 2).

2 – Automatic selection gate

This gate was used both to control milking access for all cows, as well as to limit access to the cow-calf contact area (see 4) only to treatment cows. When a cow entered the selection gate, she was directed 1 of 3 different ways, as indicated by the arrows. If she was due to be milked, she was directed to the left towards the waiting area and milking robot. Otherwise, the gate made a selection choice based on whether she was control or treatment. Treatment cows were directed to the right, towards the cow-calf contact area, while control cows were directed straight forwards, entering the general lying area.

3 – Waiting area and milking robot

This area contained a large waiting area with slatted floors, in which cows could queue for the automatic milking robot. A water cup was available in this area as well. Once in the milking robot, each cow was offered a small amount of concentrate. The milking robot exited back into the feed alley.

4 – Cow-calf contact area

In this area, treatment cows and calves had access to full contact with one another, allowing calves the ability to suckle when hungry. Due to setup of the experimental pen, cow-calf contact was considered to be cow-driven, meaning cows had the ability to initiate or end contact with calves by entering or exiting this area. Stalls were a shared resource between cows and calves, while cows also had access to 2 concentrate feeding stations. From the cow-calf contact area, cows could enter either the feed alley or the general lying area.

5 – Calf creep

Calves had access to an additional area known as the calf creep. Calves could move freely between the cow-calf contact area and calf creep, while cows were unable to access this area. The calf creep contained roughage and concentrate for the calves, and the stalls were bedded with a layer of sawdust to provide a comfortable lying area. Water was available to the calves just outside the creep.

6 – General lying area

This remaining area of the pen was accessible to all cows, and contained stalls and concentrate feeding stations. Cows could move freely between the two alleys containing stalls, but if they wanted to enter the feed alley, this was only possible through one-way gates.

Batch number 2, a group of 22 KoKalv pairs was introduced into the system in March and April 2020. They were kept indoors in a system similar to what the first group had, with the calf creep placed in a different way, until released to pasture in mid-May. After that, the calf creep and the contact area have been outside at pasture and the cows have also had access to the indoor environment.

Weaning and separation

The calves and cows were separated on pasture when the calves were 14-20 weeks old, by being allowed to walk on either side of a fence. Two weeks before the separation, the calves had been weaned from milk by getting a plastic tray in their nose that prevented them from suckling.

Barn design

Starting in batch 2, a separate calf creep was built adjacent to the existing structure of the pen. The cow-calf contact area was thus also moved from its original placement to instead run parallel to the new calf creep. Arrows indicate the direction of cow traffic throughout the pen. Concentrate feeding stations are marked with a ‘C’.

1 – Feed alley

In this part of the pen, cows had free access to silage, water and a pair of cow brushes. Silage was available in individual feed bins which facilitated the recording of feed intake for each individual cow. The only available exit from the feed alley was through an automatic selection gate (see 2).

2 – Automatisk selektionsgrind

This gate was used both to control milking access for all cows, as well as to limit access to the cow-calf contact area (see 4) only to treatment cows. When a cow entered the selection gate, she was directed 1 of 3 different ways, as indicated by the arrows. If she was due to be milked, she was directed to the left towards the waiting area and milking robot. Otherwise, the gate made a selection choice based on whether she was control or treatment. Treatment cows were directed straight ahead towards the cow-calf contact area, while control cows were directed towards the right, where the larger, general lying area was situated.

3 – Waiting area and milking robot

This area contained a large waiting area with slatted floors, in which cows could queue for the automatic milking robot. A water cup was available in this area as well. Once in the milking robot, each cow was offered a small amount of concentrate. The milking robot exited back into the feed alley.

4 – Cow-calf contact area

In this area, treatment cows and calves had access to full contact with one another, allowing calves the ability to suckle when hungry. Due to setup of the experimental pen, cow-calf contact was considered to be cow-driven, meaning cows had the ability to initiate or end contact with calves by entering or exiting this area. Stalls were a shared resource between cows and calves, while cows also had access to 2 concentrate feeding stations. Weighted one-way gates were situated both at the entrance and exit to the cow-calf contact area, which prevented calves from entering other parts of the barn.

5 – Calf creep

Calves also had exclusive access to a deep-bedded area known as the calf creep. In this area, calves had free access to roughage and water, as well as access to concentrate via a pair of calf feeding stations. Calves could move between the creep and cow-calf contact area via the fronts of the stalls. The calf creep also bordered a section of stalls in the general lying area, although these two areas were separated by a metal fence which largely restricted the possibility for any physical contact.

6 – General lying area

This remaining area of the pen was accessible to all cows, including treatment cows, and contained stalls and concentrate feeding stations. Cows could move freely between the two alleys containing stalls, but if they wanted to enter the feed alley, this was only possible through one-way gates.

The third batch in the research project began on the 1st of September 2020, and included 19 cow-calf pairs, as well 18 control cows and 18 control calves. The control cows were housed in the same pen, but without access to a designated cow-calf contact area, while control calves were group housed in a completely separate area of the barn. One large difference between this batch and previous batches was the fact that it took place entirely indoors. The pen setup, however, remained largely the same as in Batch 2, although the calf creep was enlarged to accommodate the growing calves.

Having the batch remain indoors allowed the research team to record the entire experiment with cameras, positioned strategically overhead to capture every aspect of the pen. To facilitate identification of individuals for behavioural observations, all cows were marked with symbols on a weekly basis with animal-safe paint, while treatment calves wore differently-coloured collars. So far, observations collected from these video recordings has been combined with data collected from various sensor equipment (i.e. feed bins, activity monitors) to explore time budgets and lying behaviour of both treatment and control cows within this system. The video recordings will likely be used to answer further research questions in the future as well.

Weaning and separation

Two different separation strategies were applied to the 19 dam-raised calves as part of a thesis project (Bruhn 2021). At approximately 4 months of age, half of the calves were subject to weaning via nose flaps, which were worn for 14 days, after which they were abruptly separated from their dams and moved to a separate area of the barn. The remaining calves were instead gradually separated; they wore nose flaps for 7 days, followed by being physically separated from the cows by a fence for an additional 7 days. During this period of fence-line contact, cows and calves were still able to see, hear and smell one another, as well as engage in restricted physical contact (i.e. touching noses). After 14 days, these calves were also removed from the experimental pen and moved to a different area of the barn.

Barn design

Here is an overview of the pen utilized in Batches 3, 4 and 7. The direction of cow traffic is indicated by one-way arrows. Concentrate feeding stations are marked with a ‘C’.

1 – Feed alley

In this part of the pen, cows had free access to silage, water and a pair of cow brushes. Silage was available in individual feed bins which facilitated the recording of feed intake for each individual cow. The only available exit from the feed alley was through an automatic selection gate (see 2).

2 – Automatic selection gate

This gate was used both to control milking access for all cows, as well as to limit access to the cow-calf contact area (see 4) only to treatment cows. When a cow entered the selection gate, she was directed 1 of 3 different ways, as indicated by the arrows. If it had been at least 8 hours since her last machine milking, she was directed to the left towards the waiting area and milking robot. If she was not due to be milked, the gate made a selection choice based on whether she was control or treatment. Treatment cows were directed straight ahead towards the cow-calf contact area, while control cows were directed towards the right, where the larger, general lying area was situated.

3 – Waiting area and milking robot

This area contained a large waiting area with slatted floors, in which cows could queue for the automatic milking robot. A water cup was available in this area as well. Once in the milking robot, each cow was offered a small amount of concentrate. The milking robot exited back into the feed alley.

4 – Cow-calf contact area

In this area, treatment cows and calves had access to full contact with one another, allowing calves the ability to suckle when hungry. Due to setup of the experimental pen, cow-calf contact was considered to be cow-driven, meaning cows had the ability to initiate or end contact with calves by entering or exiting this area. Stalls were a shared resource between cows and calves, while cows also had access to 2 concentrate feeding stations. Weighted one-way gates were situated both at the entrance and exit to the cow-calf contact area, which prevented calves from entering other parts of the barn.

5 – Calf creep

Calves also had exclusive access to a deep-bedded area known as the calf creep. In this area, calves had free access to roughage and water, as well as access to concentrate via a pair of calf feeding stations. Calves could move between the creep and cow-calf contact area via the fronts of the stalls. The calf creep also bordered a section of stalls in the general lying area, although these two areas were separated by a metal fence which largely restricted the possibility for any physical contact.

6 – General lying area

This remaining area of the pen was accessible to all cows, and contained stalls and concentrate feeding stations. Cows could move freely between the two alleys containing stalls, but if they wanted to enter the feed alley, this was only possible through one-way gates.

A fourth batch was initiated February 2021, this time including 14 cow-calf pairs. One of the primary aims of this batch was to test two different lengths of cow-calf contact: separation at 4 months and at 8 months of age. This was partially done so as to see if any indications of natural weaning – either by cows or calves – could be observed prior to weaning at a late stage. As with the second batch, the cows and calves were housed indoors until pasture turn-out later in the spring. At one end of the pasture, the calves had exclusive access to a fenced-off area containing a sheltered deep-bedded area, as well as silage and water. Cow-calf pairs could interact in the remaining pasture area, while cows were free to move between the indoor pen and pasture as they pleased.

Photo (coming soon)

Photo (coming soon)

Weaning at 4 months

The calves were randomly assigned to either of the 2 treatment groups, and 7 of the calves were equipped with nose flaps in early July 2021, when they were approximately 4 months old. The nose flaps were worn for 3 days before they were removed and the calves were moved into an adjacent pasture. This new pasture shared the same shelter as before, although the deep-bedded lying area for the newly-separated calves was separated from the other calves with a solid wall. Cows whose calves belonged to the 4-month separation treatment were no longer allowed access to the pasture shared with calves, and instead were redirected to a further, adjacent pasture. At the end of this pasture area, the cows could access restricted contact with the calves over a section of wooden fencing. Live observations were conducted outside to explore various social behaviours – both between calves and cow-calf pairs – and play behaviours in the two treatment groups.

Photo (coming soon)

Weaning the remaining calves

The second group of calves was originally planned to remain with their dams until they were approximately 8 months old. This length of time was decreased to 6 months when at least 1 cow began directing reproductive behaviours towards a calf. Mounting and standing to be mounted are natural behaviours performed by cows when they are in heat, but can present a dangerous situation for calves due to the size discrepancy. Due to concerns that the nose flaps used previously were causing the development of sores in the nasal cavity, the calves in this group were weaned and separated abruptly.

Barn design

Here is an overview of the pen utilized in Batches 3, 4 and 7. The direction of cow traffic is indicated by one-way arrows. Concentrate feeding stations are marked with a ‘C’.

1 – Feed alley

In this part of the pen, cows had free access to silage, water and a pair of cow brushes. Silage was available in individual feed bins which facilitated the recording of feed intake for each individual cow. The only available exit from the feed alley was through an automatic selection gate (see 2).

2 – Automatic selection gate

This gate was used both to control milking access for all cows, as well as to limit access to the cow-calf contact area (see 4) only to treatment cows. When a cow entered the selection gate, she was directed 1 of 3 different ways, as indicated by the arrows. If it had been at least 8 hours since her last machine milking, she was directed to the left towards the waiting area and milking robot. If she was not due to be milked, the gate made a selection choice based on whether she was control or treatment. Treatment cows were directed straight ahead towards the cow-calf contact area, while control cows were directed towards the right, where the larger, general lying area was situated.

3 – Waiting area and milking robot

This area contained a large waiting area with slatted floors, in which cows could queue for the automatic milking robot. A water cup was available in this area as well. Once in the milking robot, each cow was offered a small amount of concentrate. The milking robot exited back into the feed alley.

4 – Cow-calf contact area

In this area, treatment cows and calves had access to full contact with one another, allowing calves the ability to suckle when hungry. Due to setup of the experimental pen, cow-calf contact was considered to be cow-driven, meaning cows had the ability to initiate or end contact with calves by entering or exiting this area. Stalls were a shared resource between cows and calves, while cows also had access to 2 concentrate feeding stations. Weighted one-way gates were situated both at the entrance and exit to the cow-calf contact area, which prevented calves from entering other parts of the barn.

5 – Calf creep

Calves also had exclusive access to a deep-bedded area known as the calf creep. In this area, calves had free access to roughage and water, as well as access to concentrate via a pair of calf feeding stations. Calves could move between the creep and cow-calf contact area via the fronts of the stalls. The calf creep also bordered a section of stalls in the general lying area, although these two areas were separated by a metal fence which largely restricted the possibility for any physical contact.

6 – General lying area

This remaining area of the pen was accessible to all cows, and contained stalls and concentrate feeding stations. Cows could move freely between the two alleys containing stalls, but if they wanted to enter the feed alley, this was only possible through one-way gates.

Enrolment of animals for Batch 5 began February 2, 2022 and continued for 6 weeks. A total of 25 cows and 26 heifer calves were included (1 set of twins). There are multiple large differences between this batch and previous batches. Firstly, this batch utilized a different indoor pen than that previously used. This new pen was smaller and operated with a free traffic system, as opposed to the Feed First system (DeLaval) that was previously in place for batches 1–4. The cows could thus move freely between the different resources in the pen, including the feed alley, stalls and automatic milking robot. In order to encourage cows to enter the milking robot at least twice per day, the 2 concentrate feeding stations were turned off, and instead, the cows received higher rations of concentrate in the robot and mixed into their silage. This system of free cow traffic was successful; many cows entered the robot of their own free will more than twice per day, either for additional milkings or simply for a portion of concentrate.

Photo (coming soon)

Photo (coming soon)

Photo (coming soon)

A second large change in this new batch was the elimination of a cow-calf contact area. Instead, the entire pen was occupied only by the cow-calf pairs and triad, and – with the exception of the milking robot and waiting area – the calves had access to the entire unit and its resources. As before, a calf creep was located along one side of the pen, providing calves with a separate lying area. Water, roughage, and concentrate were also available to the calves within the creep.

In May, the cows and calves were turned out to pasture, where we can note a third difference from previous batches. Much like their dams, the calves were able to move freely between the indoor pen and outdoor pasture, and could continue to do so until weaning.

Photo (coming soon)

Photo (coming soon)

Four and six month treatment groups

As in batch 4, this batch once again randomly allocated each of the calves to 1 of 2 different treatments: weaning and separation at either 4 or 6 months of age. Calves were weaned via fenceline separation, and their behaviours were monitored via direct observations and accelerometers both before and after weaning. Weaned calves were moved to a separate, adjacent pasture where they had access to shelter, food and water. During the fenceline separation period, which lasted 4 weeks following each weaning, cows and calves could have restricted physical contact across the fence.

Cows with and without experience of these systems

Another unique aspect of this particular batch was the fact that some of the cows were previously raised as calves in earlier batches of the Cow and Calf Together project. These cows – all primiparous – made up 1 of 4 unique categories of dams found in this batch, the others being:

• Primiparous cows that were conventionally raised
• Multiparous cows who had experience raising calves in a cow-calf contact system
• Multiparous cows with no previous experience

Video cameras were installed over each of the individual calving boxes to facilitate observations of maternal behaviour at a later point. Furthermore, all of the cows were equipped with various sensor equipment that can detect activity patterns and estrus behaviour. This behavioural data will be combined with other automatically-collected data (i.e., milk yield) to observe how cows that were previously raised in a cow-calf contact system perform during their first lactation. Milking, feed intake and fertility data are also available for such cows not currently housed in a cow-calf contact system, and will be analysed as well.

Barn design

Batch 5 takes place in an entirely different pen from batches 1-4. Cow traffic is free throughout the pen, although cow flow through the milking robot is unidirectional, as indicated by the one-way arrows. Concentrate feeding stations are marked with a ‘C’, although they were not in use for the duration of this batch.

1 – Feed alley

In this alley, cows have free access to silage through individual feed bins, as well as from a feedbunk with headlocks. A small section of the feedbunk has been outfitted with a post and rail feed barrier, as well as a trough to lift the feed up from the feed table; this is to allow calves to access silage and feed alongside cows. Cows and calves also have free access to water via a trough, salt licks, as well as a single swinging cow brush.

2 – Waiting area and milking robot

This is the only area of the pen not accessible to calves. Cows can enter the waiting area by means of a weighted one-way gate; a second one-way gate is situated at the exit from the milking robot, which leads into the feed alley. The milking robot is programmed to second as a concentrate feeding station, meaning cows can pass through the robot voluntarily and receive a portion of concentrate without necessarily being milked each time.

3 – Lying area

The lying area is an alley with a row of stalls lining either side. The stalls are bedded with mattresses and a layer of wood shavings, and are free for use by both calves and cows.

4 – Calf creep

Calves have exclusive access to a separate, deep-bedded area containing roughage, water via 2 water cups, and a pair of calf feeding stations that provide concentrate. Calves can move between the calf creep and rest of the pen via the fronts of the adjacent stalls.

Similar to Batch 5, this batch took place in early 2023 with free cow traffic and calf-driven CCC, but was smaller in scale, with only 10 dam-calf pairs enrolled. When calves were an average of 8 weeks old, they were transitioned from 24-h to 12-h contact. During the 12-h contact period, all calves were rounded up into the calf creep each night and released back into the cow pen the next morning. The barrier between the calf creep and cow pen was a metal fence, meaning that calves and cows could still hear and (for the most part) see one another. During the nights, calves had unlimited access to solid foods and water. Additionally, the calves were fed whole milk from teat buckets just before being released each morning. 

The 12-h contact period persisted for 6.5 weeks, after which calves were fully housed in the calf creep for an additional 3.5 weeks with 0-h physical contact and then moved to another part of the barn. Calves were weaned gradually from milk over 12 days, starting 1 week after the initiation of 0-h contact. Cow behaviour, as well as milk yield, was studied during the 24-h, 12-h and 0-h contact periods. Additionally, calf growth rates were observed during these periods, allowing us to work towards disentangling the effects of the loss in physical dam-calf contact from the loss of milk.

Barn design

Batch 6 was conducted in the same pen as in round 5, but only part of the pen was used due to the smaller number of cow-calf pairs.

1 – Feed alley

In this alley, cows have free access to silage through individual feed bins, as well as from a feedbunk with headlocks. A small section of the feedbunk has been outfitted with a post and rail feed barrier, as well as a trough to lift the feed up from the feed table; this is to allow calves to access silage and feed alongside cows. Cows and calves also have free access to water via a trough, salt licks, as well as a single swinging cow brush.

2 – Waiting area and milking robot

This is the only area of the pen not accessible to calves. Cows can enter the waiting area by means of a weighted one-way gate; a second one-way gate is situated at the exit from the milking robot, which leads into the feed alley. The milking robot is programmed to second as a concentrate feeding station, meaning cows can pass through the robot voluntarily and receive a portion of concentrate without necessarily being milked each time.

3 – Lying area

The lying area is an alley with a row of stalls lining either side. The stalls are bedded with mattresses and a layer of wood shavings, and are free for use by both calves and cows.

4 – Calf creep

Calves have exclusive access to a separate, deep-bedded area containing roughage, water via 2 water cups, and a pair of calf feeding stations that provide concentrate. Calves can move between the calf creep and rest of the pen via the fronts of the adjacent stalls. 

Enrolment for the seventh batch of this project started on the 1st of October, 2023 and continued until the 25th of November. A total of 40 cows along with their 43 calves (including 3 pairs of twins) were included in this batch: 20 cow-calf pairs (CCC) and 20 conventionally (CONV) managed cows and their 22 calves. The barn layout was similar to Batches 3 and 4, where CONV cows were housed together with CCC cows and calves, but without access to the designated CCC area (see barn design below). Batch 7 included 11 primiparous and 29 multiparous cows, of which 12 were Swedish Holstein and 28 Swedish Red breeds. Bull and heifer calves were also included and were either dairy breed or crossbred with Limousine or Angus beef breeds. 

Weaning and separation

Early January 2024 we started weaning the first half of the calves: CCC calves were weaned over 10 days via a fence-line allowing suckling and physical contact, while CONV calves were gradually weaned by reducing milk allowance. Calves were fully weaned at the earliest age of 12 weeks. 

For weaning the CCC calves, a fence/gate(?) was placed in the upper part of the CCC area and the calf creep was split in two, so that the younger calves could still have unrestricted contact with the cows. Calves being weaned were placed behind the fence and had the possibility to suckle by placing their heads through the fenceline when a cow was standing on the other side. Suckling through the fence-line was allowed for 24 h per day for the first 4 days of weaning, whereafter suckling time gradually decreased until the fence-line was blocked off after 10 days. The calves could then stay behind the fenceline and have physical contact with the cows for another week, but suckling was not possible. The thought behind this gradual fence-line weaning method was to first allow calves to get used to suckling through the fence-line and then gradually reduce suckling allowance with the hopes to stimulate solid feed intake of the CCC calves. All cows and calves were followed until 4 weeks after weaning. 

Measurements

Throughout the study, milk yield in the AMS of all cows was recorded, as well as feed intake, early lactation clinical health, and blood samples for metabolic outcomes. Calves were assessed for clinical health, weighed, and blood sampled at 9 occasions throughout the study, and we performed ultrasounds to measure their backfat thickness. Live behavioural observations were done before, during and after weaning and separation of cow and calf to get an insight into weaning behaviour and the effects of the weaning strategy. 

Barn design

Batch 7 was managed in the same pen as in Batch 3 and 4, The direction of cow traffic is indicated by one-way arrows. Concentrate feeding stations are marked with a ‘C’.

1 – Feed alley

In this part of the pen, cows had free access to silage, water and a pair of cow brushes. Silage was available in individual feed bins which facilitated the recording of feed intake for each individual cow. The only available exit from the feed alley was through an automatic selection gate (see 2).

2 – Automatic selection gate

This gate was used both to control milking access for all cows, as well as to limit access to the cow-calf contact area (see 4) only to treatment cows. When a cow entered the selection gate, she was directed 1 of 3 different ways, as indicated by the arrows. If it had been at least 8 hours since her last machine milking, she was directed to the left towards the waiting area and milking robot. If she was not due to be milked, the gate made a selection choice based on whether she was control or treatment. Treatment cows were directed straight ahead towards the cow-calf contact area, while control cows were directed towards the right, where the larger, general lying area was situated.

3 – Waiting area and milking robot

This area contained a large waiting area with slatted floors, in which cows could queue for the automatic milking robot. A water cup was available in this area as well. Once in the milking robot, each cow was offered a small amount of concentrate. The milking robot exited back into the feed alley.

4 – Cow-calf contact area

In this area, treatment cows and calves had access to full contact with one another, allowing calves the ability to suckle when hungry. Due to setup of the experimental pen, cow-calf contact was considered to be cow-driven, meaning cows had the ability to initiate or end contact with calves by entering or exiting this area. Stalls were a shared resource between cows and calves, while cows also had access to 2 concentrate feeding stations. Weighted one-way gates were situated both at the entrance and exit to the cow-calf contact area, which prevented calves from entering other parts of the barn.

5 – Calf creep

Calves also had exclusive access to a deep-bedded area known as the calf creep. In this area, calves had free access to roughage and water, as well as access to concentrate via a pair of calf feeding stations. Calves could move between the creep and cow-calf contact area via the fronts of the stalls. The calf creep also bordered a section of stalls in the general lying area, although these two areas were separated by a metal fence which largely restricted the possibility for any physical contact.

6 – General lying area

This remaining area of the pen was accessible to all cows, and contained stalls and concentrate feeding stations. Cows could move freely between the two alleys containing stalls, but if they wanted to enter the feed alley, this was only possible through one-way gates.