In 2018, UK supermarket giant Tesco banned its dairy producers from individually housing dairy calves. According to Dr. Jennifer Van Os, assistant professor and Extension specialist of animal welfare at University of Wisconsin-Madison, this trend toward social housing may someday become the norm in the U.S.

Van Os, along with Dr. Melissa Cantor, a Penn State assistant professor of precision dairy science, discussed social housing for dairy calves at an April Dairy Cattle Welfare Council meeting.

Benefits of Social Housing

Social housing includes pairing dairy calves or putting them into groups. One benefit of social housing reflects the simple fact that cattle are a herd species and having contact with same-aged peers is a natural behavior.

“Calves will work really hard to gain access to contact with their peers, and when they are housed in groups, they prefer to be in close proximity,” Van Os said.

Van Os explained studies show that when calves are raised socially and eventually enter a milking herd, they have a higher social dominance rank. They’re better able to gain access to resources – not because they’re more aggressive, but because they know how to interact appropriately.

Studies have also shown that when calves are raised in pairs or groups, they’re more resilient to stress, particularly during weaning. The scientific principle behind this is called social buffering – by having social companions, calves are better able to withstand stress.

Social housing can also help in terms of cognitive development; calves are better able to learn and process changes, and they also adapt more successfully to new situations. For example, a socially housed dairy calf will likely be more successful when it’s time to transition from a bred heifer group to learning how to navigate the milking parlor or an automated milking system.

There are also performance benefits to social rearing. Cantor said, “There’s quite a few studies at this point that calves that are socially housed together, usually in pairs, compared to individual housing, have been associated with solid feed intake. So, greater starter grain uptake in these calves and also average daily gain as well.”

It’s important to note that six studies found that this positive effect of grain intake and growth associated with paired housing occurred in farms that were feeding at least seven liters a day of milk or milk replacer to their Holstein calves.

Making the move to social calf housing

Social housing can be as simple as placing fencing around two hutches so the calves can interact. Photo courtesy of Van Os Lab/UW-Madison

Practical Recommendations for Social Housing

Based on veterinary recommendations, Cantor and Van Os suggested that there should be no more than a 14-day age difference between the oldest and youngest calf within a pair or a group. Ideally, there should be no more than a week difference.

“If you have a larger age gap you can see greater competition for feed as well as risk for disease transmission,” Van Os said.

Two-thirds of veterinarians surveyed by Van Os said they prefer to have calves moved into social housing when they are two weeks old or less. There’s limited scientific evidence to support this at this time, but some studies suggest that if you put calves into social housing earlier there may be growth performance benefits, better learning abilities and cognitive growth.

In terms of group size, 15 calves or more is considered a risk factor, according to Cantor. If a producer is considering installing an automated calf feeder that can feed 20 calves, they should consider that as soon as the group size grows larger than 15, it starts to put disease pressure, such as respiratory diseases, on the calves.

It’s also important to avoid dynamic group housing, where younger calves enter a group as older ones leave, and instead use an “all-in, all-out” group management.

It’s not necessary to build a new barn to implement social housing. Van Os showed an example of adapting prefabricated individual hutches into social housing by fencing around two hutches, allowing for interaction between pairs of calves. In any system, for it to be considered true social housing, the calves must have full social contact. Fence line contact between calves is not full social contact, according to Van Os.

Transitioning to Social Housing

“Calf health is multifactorial, meaning there are many different factors that can contribute to calf health or calf morbidity. A lot of the same principles for good health outcomes apply whether you’re housing calves individually or in pairs or groups,” Van Os said.

Prior to transitioning to social housing, producers should take a frank look at their systems for preventative care and monitoring including colostrum management, nutrition, hygiene practices, ventilation, space allowance and bedding material and management.

Before transitioning to social housing, Cantor and Van Os recommended having a pre-weaned (24 hours to 60 days) calf mortality rate of less than 3% (this does not include stillbirths).

Colostrum management and feeding is also critical prior to transitioning to social housing. At least 40% of calves should have at least 25 g/L of immunoglobulin G (IgG) with a serum Brix of at least 9.4%. Ideally, less than 5% of calves should have “poor” transfer, meaning less than 10 g/L of IgG with a serum Brix of less than 8.1%.

These, however, are not magic numbers, but rather benchmarks. “It’s not a one size fits all,” Van Os said. “However, there’s a lot of different balls in the air, and it’s easy to drop one. This is why if you are transitioning to pairs or especially larger groups, it’s important to make sure all of these different ducks are in a row.”

Those who want to learn more can visit animalwelfare.cals.wisc.edu/calf_pairing.

by Sonja Heyck-Merlin