For years, dairy calves have been housed individually, primarily for disease prevention. However, there’s significant evidence showing calves benefit from group housing.
Dr. Melissa Cantor, assistant professor of precision theory science, Penn State, said housing calves in pairs is becoming more popular.
It’s known that cows have difficulty unlearning habits: they prefer a certain stall or side of the parlor, and such tendencies begin in calfhood. Interaction between two or more calves promotes social skills, competitiveness and adjustment to new environments. Calves raised individually have a difficult time adjusting to new scenarios. They are often more aggressive and fearful, don’t compete as well and have poor social ranking.
“Calves [housed in pairs] learn better,” said Cantor. “They reverse-learn tasks much more easily. We also know that when we house calves individually, they have a harder time with new food.”
In one study, chopped carrots were offered to calves to see how long it would take them to try new food. “Individually housed calves consumed much less of the new food compared to socially housed calves,” said Cantor. “It took almost three hours for individually housed calves to touch carrots and longer to eat them. For calves raised with access to other calves or their mothers, it took a lot less time.”
Calf health is a concern when they’re exposed to others, but calves in triplet and pair housing have not been observed to have poorer health than individually housed calves. However, farmers must pay close attention to details to maintain health in pairs or groups.
“We can’t change individual housing to something more complicated without having the basics correct,” said Cantor. “Testing colostrum isn’t enough – blood serum should be tested to ensure calves are in good and excellent categories. According to USDA data, 90% of calves are already passing [a blood serum test]. We need to push to get numbers higher.”
Cantor suggested calves in pair or group housing should be tested at 24 to 72 of age for an accurate measure of serum total protein rate (STP). A reasonable goal is 40% or more calves with an STP of over 6.2. Calves simply passing a STP is not enough to make social housing work well. The goal is to ensure calves have herd immunity to lower the risk of respiratory illness.
Overall farm cleanliness aids in successful social housing. Everything from calf chains to feeding tubes and nipples should be cleaned and sanitized properly and stored in a clean environment.
There are biological benefits to social rearing. New literature on cold stress shows that paired calves keep the hutch warmer because they’re using one another for warmth.
“We can also promote feeding more milk to calves to encourage more milk in the first lactation,” said Cantor. “For every bit of average daily gain we get in calves before weaning, there’s increased milk production. Pair housed calves should be offered more milk.”
Studies have show that individually housed calves never have better growth than pairs. There’s improvement in dry matter intake, average daily gain and weaning weight. Growth results depend on whether calves are offered sufficient milk.
“Farm research finds that calves improve grain intake more often than not,” said Cantor. “That seems to be the biggest benefit. But that’s only observed if calves are offered at least seven liters of milk per day. If farmers offer the conventional four to six liters of milk (six quarts/day), they shouldn’t do pair housing because there won’t be any growth benefits. There might be social benefits but not growth.”
Cantor suggested offering calves at least 7.5 liters of milk daily.
Socially raised calves cannot be weaned abruptly. “The rumen is not functional for the first one to 15 days,” said Cantor. “It does hardly anything, so it’s important that farms feed milk for that reason alone. It’s the only source of calories a calf can metabolize at this young age.”
Weaning calves so early means their entire foregut must develop quickly. The abomasum becomes 7% of the digestive capacity after weaning. The rumen undergoes a massive expansion from 25% of gut capacity to 80% after weaning.
“If we are not appropriately step-down weaning calves over at least seven days, there will be problems,” said Cantor. “You’re putting all those calories into that calf and paying for growth, so you want to maintain growth after weaning without slumps. The way to do that is slow, step-down weaning.”
Feed a good, 20% crude protein grain to help calves develop rumen papillae. She urged farmers to feed calves 4 lbs. of grain daily before weaning to prime the rumen.
“Offer low-quality hay so starter intake isn’t limited,” said Cantor. “First-cut alfalfa isn’t always the right hay for heifers because they may choose that over starter, although many farms are successful feeding alfalfa hay.” Calves also need access to clean water.
Social housing isn’t perfect, especially if there’s a large age gap between calves in a pair. “There is no research on how much space to offer pair housed calves,” said Cantor. “Thirty square feet is a number but more research is necessary. We also need to remember that cross-sucking is a bigger problem if milk is limit fed. The more milk is restricted, the more you’ll see that in early life. However, the more milk you feed, the greater chance of cross-sucking if they aren’t weaned correctly. There’s a balance … Sometimes people forget that post-weaning nutrition is equally important to limit cross-sucking. Calves usually cross-suckle because they’re hungry.”
Restricted environments lead to abnormal behavior such as pen sucking, cross-sucking and pushing other calves. Open bucket feeding encourages these habits. Solutions for behavioral issues include providing things for calves to do.
“Calves will play with brushes, ropes, chains and balls,” said Cantor. “If those items are removed, calves will seek them out.”
Farmers who plan to transition calves from individual pens to pair or group housing should work with their herd veterinarian to ensure all aspects of health and nutrition are fully covered.
