Mother Nature has not been kind to baby calves this summer. With extended periods of high temperatures, the devastating impact of heat on young cattle has made headlines. According to Tom Earleywine, Land O’Lakes Animal Milk Products technical services director, there are a few things dairy producers can do to minimize heat stress and prevent death loss among this vulnerable segment of the herd.
Earleywine notes that dehydration is the “big factor” behind sudden death loss in calves. Loss of electrolytes occurs when calves respirate and sweat in effort to cool themselves, and the consequence of imbalanced electrolytes can be death. “The problem is that once the calf is overheated, it is not good at getting rid of it,” he says, noting the small body mass relative to surface area of a baby calf’s body. Further, newborn calves have very little body reserves to draw from if they go off of feed.
“The other part is to try to get them to drink more water because hydration is so critical at this point,” he adds. Sometimes calves do not seem interested in drinking water, but they may respond to electrolytes, which he says tend to be quite palatable.
Bette Nowobielski, a dairy producer in the Thorp area, added electrolytes to her calf program for the first time this summer, and she has been quite pleased with the results. “I think they are much perkier with the electrolytes because they don’t feel the extra stress,” she shares. “It helps improve their attitudes. They are more comfortable, and it provides for better hydration. It helps them feel better, too.”
Nowobielski raises around 20 calves at a time for the 200-cow dairy she and her husband Ed own and operate. With the guidance of their Land O’Lakes consultant, she incorporated electrolytes as a treatment for calves showing signs of sickness like loose manure and lack of appetite. Her protocol includes mixing the electrolyte in with water after the morning and evening feedings consistently for five days. When things really heated up this summer, she added electrolytes as a preventative measure for all of her calves.
“I had a couple of scouring calves, so I implemented electrolytes to hydrate them. This kept their feed intake up and gave them the extra nutrients and the ability to retain hydration,” she notes. “Sick calves usually recover within two days of getting electrolytes morning and night. That’s why it is so important to be proactive. They recover much more quickly.”
When providing electrolytes during a heat wave, timing can influence a calf’s intake. Earleywine encourages producers to consider a night feeding. “If you are feeding at 5 p.m. or 6 p.m. in evening, come back with electrolytes at 9 p.m. Hopefully, it will be cooler at that time of day and the calves may be more apt to come drink than at the hottest part of day,” he says. “I have seen it happen where calves were offered free choice electrolytes and didn’t drink it because they didn’t want to come out into sun.”
Nowobielski has taken a few other measures to keep her calves healthy. She provides fresh water three times each day during very hot weather. To provide better ventilation in the calf hutches, she places blocks underneath for improved air flow. “As long as they have good ventilation and plenty to drink, that’s what has helped them get through it,” she adds.
Earleywine notes the benefits of these steps, and he further warns producers that providing shade over the corral area of a calf hutch can be another critical piece of the puzzle. The temperature inside the hutch can elevate quickly as the sun beats down. “The best way to test that is to grab a thermometer and jump into the hutch,” he says. “We have found some that are 115 degrees F inside when it is 100 degrees outside.”
Some producers have even moved their calves out of hutches in favor of buildings to provide better shade and ventilation. Open-sided structures or a building with a forced air tube provide the best ventilation. If that is not an option, barn fans can aid in cooling calves as well. When moving calves into a group, be sure to include enough space. “While we typically want 25 square feet per calf, in this weather we need 35 to 40 square feet per calf so they do not get overcrowded,” he says.
Earleywine also tells producers that even though things will eventually cool off, the impacts of heat stress will linger. This not only effects the calves that were on the ground during the thick of things, but also the calves that heat-stressed cows were carrying during that time. “Calves born after heat stress still have the impact of heat stress because mom was dealing with it,” he says. For this reason, he suggests extra monitoring of calves and testing colostrum to ensure quality.
Producers should also consider providing calves with extra nutrients to make up for the body reserves that typically would be stored during their first few weeks of life. “Normally, calves that would have built up body condition by now will not have [those reserves available] because of heat stress. With very, very low body fat, they will never have a chance to get to normal body fat level. Make up for it now,” Earleywine suggests. He recommends feeding a milk replacer specifically formulated for warm weather and upping the amount. While 1 to 1.25 pounds of dry matter (DM) from the milk replacer is usually what is recommended, that is not enough now, he says. Provide calves with as much as 2 to 3 pounds of DM per day to bring them to a higher plane of nutrition. If feeding pasteurized milk, there are products available that can be added to boost DM.
He says that he has seen an increased incidence of septicemia this summer, a bacterial infection in the calf’s blood. Current conditions provide the ideal environment for bacteria to grow, and a susceptible young calf can quickly become infected by picking up pathogens like E. coli and Salmonella from their environment. This is why properly cleaning and sanitizing areas like the calving pen and hutches is critical. Cleanliness will also deter flies from populating in these areas, further reducing the stress load on calves.