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Making the transition to pair-housed calves: Two heads are better than one

Joao H.C. Costa, Melissa C. Cantor, Heather W. Neave and Maria E. Reis for Progressive Dairy Published on 31 July 2020
Pair housing

Pair housing (or small groups of up to four calves) for pre-weaned calves is increasing in popularity due to the myriad of benefits for calf welfare compared to individual housing.

Converting to pair housing is also appealing as a steppingstone to group housing, because the management transition is simpler compared to management of a large group of calves.

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While calves in individual housing generally have visual and auditory contact with other calves, pair housing provides calves with direct access to a companion. A growing body of research shows that calves raised with another calf, or in a group of calves, have several advantages over those raised alone. This research also counters long-standing concerns that farmers typically associate with pair housing. There are many benefits and practical tips which we share here.

Performance benefit: Pair housing improves feed intake and weight gain

The greatest benefits seen in pair-housed calves are when they are paired within the first few weeks of life. We compared calves paired at 3 days old, a week before weaning at 42 days old or individually housed until 10 weeks old; we found calves paired at 3 days old had the greatest advantages, particularly in growth.

Other research observed calves paired before 3 weeks old were not different than calves paired at birth. Most studies found that pair housing improved starter intake from 3 to 10 weeks old, which was reflected in better average daily gain (ADG). Specifically, early pairing gave calves a weight gain advantage of 130 grams per day over individually housed calves. The takeaway here is calves paired the earliest will eat more starter and have greater ADG, which makes the weaning transition smoother, compared to individually housed calves.

To ensure succes of pair housing is to use a nipple for feeding milkInterestingly, the performance of calves raised in pair housing systems was very similar to calves raised in larger groups or even in more complex groups (with the dam and other calves). This finding is especially compelling because it suggests contact with just one other calf offers the benefits provided by more sophisticated group housing (and consequently more sophisticated management). Nonetheless, moving to pair housing is a large steppingstone from individual housing, and it requires the farm to have a solid foundation in calf management for its success.

In order to observe the starter intake and performance benefits of pair housing, an environment that discourages competition between calves is necessary. Calves must be able to feed at the same time. A good rule-of-thumb is to ensure the feeder provides at least a muzzle width for two calves to eat side-by-side (at least 15 inches per calf or a physical division) or provide a bucket of solid feed for each.

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Furthermore, when calves are able to feed together, they are more likely to experience social facilitation (when calves do what they see their peers do – in other words, peer pressure) or social learning (when calves learn something quicker simply by observing their peers). We think these phenomena of social facilitation and social learning are why two heads think better than one, leading to greater starter intakes and performance in early life. The great news is the benefits associated with these social influences do not end with calf performance – the calf’s adaptability and cognition are also positively affected.

Cognitive benefit: Pair housing stimulates cognitive development

Research also suggests that group-housed calves, including those that are pair-housed, perform better in cognitive tasks, particularly those requiring a learning component. One study tested the learning ability and flexibility of calves in a cognitive test: Paired and individually housed calves were trained to approach a white screen to receive a milk reward and to avoid approaching a red screen (otherwise they received a time-out punishment). All calves, regardless of their housing condition, learned this initial task.

Pairing gave calves a weight gain advantage of 130 grams per day over individually housed claves

However, when the coloured screens were reversed (i.e., calves now had to approach the red screen, instead of the white, to get the milk reward), most of the individually housed calves were never able to relearn the opposite task. This seemingly simple task revealed that, in fact, calves housed alone have impaired learning ability.

In a follow-up experiment, we found this learning impairment also applied to when calves were presented with a novel feed; individually housed calves were much less likely to eat something new, while socially housed calves were able to adapt to a new diet. Individually housed calves also appear to have difficulty with social cues – when individually housed calves met an unfamiliar calf, it took longer to first approach the new calf, more time was spent in proximity to the calf (who tried to escape), and there were more attempts to engage in play, compared to pair-housed calves who explored the environment with the new calf.

Thus, individually housed calves may exhibit abnormal social behaviour, likely due to their inability to learn appropriate social cues if they had been with a housing partner. In addition, calves with a social background have a smoother transition when grouped in larger groups after weaning. Individually raised calves spent as long as 48 hours without eating and took more than a week to reach the same level of solid feed intake, compared to before grouping.

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Overall, the research shows that calves with a social companion have superior cognitive skills, including the learning of new tasks and social cues, compared to calves housed individually. How do these cognitive skills affect calves later in life? This is food for thought, as the research is still underway.

Social benefit: Calves want to be with a friend and learn from them

Pair housing provides direct social contact with a peer, but do calves want to be with another calf? Research suggests that individually housed calves will work harder to gain access to another calf by pressing more often on a weighted gate, compared to socially housed calves. Moreover, calves will maintain social partnerships in the long term; calves housed in groups until 4 months old were in contact more often with familiar peers even after moving to a new freestall barn, compared to calves raised individually. Therefore, this work suggests calves indeed are motivated and want to be with a social companion, and social relationships developed early in life are sustained.

Social contact between calves from an early age also more closely resembles their natural environment. Feral cattle will hide their calves for the first few days of life, but after reintroduction to the herd, the calf quickly forms small social groups with calves of a similar age. It is within these social groups that a calf learns to graze and which plants they should and should not eat. This type of social learning is promoted in pair-housed calves, where they learn from each other about how and what to eat (such as when they sample hay and starter), and it likely explains why socially housed calves behaved more appropriately when introduced to a new calf. Overall, the evidence is clear – calves benefit from early development of social behaviour.

Myth 1: Pair housing increases disease risk

One of the most common concerns with pairing calves is the increased risk of disease. Indeed, individual housing was established to ensure calves remained healthy by preventing direct contact with other calves. However, several large-scale studies determined there was no increased disease risk in paired calves compared to individually housed calves. Instead, the largest risk factor for calf health, regardless of housing system, was failure of passive transfer. Therefore, producers considering to pair their calves should work with their veterinarian to determine passive transfer status of their calf herd, targeting at least 80% of calves with successful passive transfer.

A solid foundation in colostrum management is fundamental for developing a successful pair housing program for calves, because this ensures each calf in the pair has the best immune system possible to cope with any pathogens. The pair must also be maintained throughout the pre-weaning period, with no contact with other paired calves – this approach limits the horizontal transmission of disease between animals. Attention to bedding cleanliness and ventilation are also critically important, as these factors will increase the risk of illness if management is poor.

Myth 2: Pair housing increases competition and cross-sucking behaviours

Two other common concerns with managing calves in pairs are the increase in competition and risk of cross-sucking. Cross-sucking is an abnormal behaviour resulting from prevention or limitation of time to suckle from a teat. One of the greatest tools to ensure success of pair housing is to use a nipple for feeding milk, which allows calves to suckle and will help to prevent cross-sucking behaviour. To limit competition between calves, an appropriate nutrition program must be provided for the calves – this includes feeding at least 8 litres per day of milk or milk replacer and free access to water.

Some producers have reported successfully reducing competition with slow-flow teats and milk bars, or providing a physical barrier between feeding stations. Pairing calves of similar ages and weights can also help reduce competition. Overall, while there is no one-size-fits-all solution for each farm, producers can often achieve best results with pair housing by using a nutrition program that feeds high volumes of milk through a teat.

In summary, there is now a wealth of research outlining the performance, cognitive and social benefits of pair housing calves. Feed intake and growth is improved, especially during weaning, and there is greater acceptance of new foods, new environments and unfamiliar calves in pair-housed calves compared to those raised individually. Pair-housed calves also demonstrate superior performance in cognitive tasks.

Calves likely perform better in pairs due to social learning that naturally teaches the calf which foods are appropriate to consume and promotes learning of social cues. However, successful pair housing requires important management practices – these include a strong colostrum program, feeding high milk allowances through a nipple and providing a barrier during feeding to reduce competition. Calves can be effectively pair-housed using animals at the same or similar age (up to two weeks age difference) from two to 10 days after birth. An easy way to create pair housing is to modify individual pens by removing the barrier between adjacent pens, or by linking the wire fencing between two hutches (but keeping two hutches for a pair of calves). All in all, pair housing can be a successful system if implemented and managed properly.  end mark

PHOTO 1: Pair housing provides direct social contact with a peer, but do calves want to be with another calf? Research suggests that individually housed calves will work harder to gain access to another calf by pressing more often on a weighted gate, compared to socially housed calves.

PHOTO 2: One of the greatest tools to ensure success of pair housing is to use a nipple for feeding milk, which allows calves to suckle and will help to prevent cross-sucking behaviour. To limit competition between calves, an appropriate nutrition program must be provided for the calves – this includes feeding at least 8 litres a day of milk or milk replacer and free access to water. 

PHOTO 3: Early pairing gave calves a weight gain advantage of 130 grams per day over individually housed calves. The takeaway here is that calves that are paired the earliest will eat more starter and have greater ADG, which makes the weaning transition smoother, compared to individually housed calves. Photos provided by Joao Costa et al.

A review discussing this finding is published in the Canadian Journal of Animal Science.

Heather W. Neave is a post-doctoral fellow at AgResearch Ltd., New Zealand.
Melissa C. Cantor is a Ph.D. student at the University of Kentucky under Dr. Costa’s supervision.
Maria E. Reis is a visiting MSc student at the University of Kentucky under Dr. Costa’s supervision.

Joao H.C. Costa
  • Joao H.C. Costa

  • Assistant Professor
  • University of Kentucky
  • Email Joao H.C. Costa

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