Severe summer drought and extreme heat heavily deplete pasture resources. One of the most effective strategies to drastically reduce a cow’s forage needs heading into late summer and fall is early weaning of calves when they are 90 to 120 days old.
According to Dr. Jess Hinrichs, Zoetis beef technical services senior veterinarian, young calves are incredibly resilient. With proper planning, early weaning can turn a seasonal challenge into a strong marketing opportunity.
“There are times when I would rather wean a 90-day-old calf instead of one that’s 7 months old,” Hinrichs explains. “Young calves can adapt quickly in a dry lot and if I’m weaning in summer weather, the temperature is more consistent than in the fall when we have those larger temperature swings.”
What is the Best Vaccination Protocol for Early-Weaned Calves?
For early weaning to succeed, safeguarding the calf’s immune system is paramount. Hinrichs encourages this strategy:
- Preweaning Vaccinations (two to three weeks prior)
Ideally, calves should be vaccinated two to three weeks before they are separated from their dams. This gives their immune system time to build a robust defense before experiencing the stress of weaning.
“If we vaccinated at branding and turnout, this is a booster for those vaccinations,” Hinrichs explains. “If we didn’t vaccinate before turnout, this dose is really important to set that calf up for success later on.” - Weaning-Day Health Protocol
On the day of weaning, Hinrichs recommends a targeted health protocol to combat respiratory pathogens and parasites:- Respiratory Protection: Administer a booster of Inforce 3 respiratory vaccine.
- Metaphylaxis: Give a metaphylactic dose of Draxxin (tulathromycin injection) Injectable Solution to reduce respiratory disease challenges in fresh, early-weaned calves.
- Parasite Control: Administer a dose of Valcor (doramectin and levamisole injection) if calves have been grazing to eliminate their parasite burden.
- Growth Promotion: Use a growth implant like Synovex Primer to add frame and weight gain during this highly efficient growth phase without adding excess condition.
How to Manage the Weaning Environment in Hot Weather
Where you house early-weaned calves is just as important as what you feed them. To manage extreme summer heat:
- Avoid Bare Dirt Lots: A bare dirt lot absorbs and radiates intense heat.
- Provide Bedding and Shade: Utilize grass traps or dry lots with clean bedding, which significantly moderates ground temperature. Ensure ample access to shade.
- Ensure Water Accessibility: Light, young calves dehydrate rapidly. Ensure fresh water sources are clean, abundant, and low enough for small-frame calves to easily reach.
“Where you wean the calves is important,” Hinrichs says. “These lightweight, young calves are prone to dehydration, so we need to make sure our water source is adequate and low enough for them to reach.”
What Should You Feed an Early-Weaned Calf?
Lightweight calves under 400 lb. have limited rumen capacity and functioning. Therefore, their diet requires precision nutrition.
“In these lightweight calves that are less than 400 lb., every bite they eat is critical,” says Blaine Corners, Zoetis beef strategic technical services team senior nutritionist. “We need to make sure they are getting the right mix of nutrients in everything they eat.”
To support the bacterial population in the calf’s developing rumen, Corners recommends a structured nutritional approach:
- Leafy, Digestible Forage. Start with high-quality, highly digestible hay containing plenty of leaves. Avoid using fat as a primary energy source, as it does not aid the development of fiber-digesting gut microbes.
“We are going to start with a diet that is foundational in forage because that is what the calf is used to and it needs to be hay with lots of leaves that are easily digestible,” Corners says. - Balanced Rumen pH and Protein Sources. To keep the rumen’s pH stable, balance the sources of protein and energy. Corners recommends sourcing:
- 50% of protein from distillers grains or corn gluten meal.
- 50% of protein from cottonseed meal (or soybean meal as a substitute).
“They complement each other in the amino acid makeup, and it doesn’t throw off the balance of the rumen,” Corners explains.
- Link Gut Health to Lung Health. A healthy digestive tract directly impacts respiratory health — a vital connection for recently weaned calves.
“Half of the calf’s immune system is focused on the digestive tract,” he says. “If we keep their gut healthy and functioning, then the immune system can focus on the lungs.”
Next Steps for Producers
Early weaning requires a customized approach. Corners and Hinrichs strongly encourage producers to collaborate with their local veterinarian and beef nutritionist to build a tailored early-weaning program.
For more information on customized vaccination and health programs from Zoetis, visit BuildingHealthyHerds.com.
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