How to Naturally Prevent Milk Fever and Ketosis in Fresh Dairy Cows

When a cow calves, her body faces an enormous physiological shift. Calcium demand spikes almost instantly with the onset of lactation, energy needs outpace intake and fluid loss from calving can leave her dehydrated and sluggish. These changes create the perfect storm for metabolic issues like milk fever and ketosis.

These conditions can quietly erode performance, delay peak milk, suppress immunity and reproduction and increase the risk of early culling. Even when symptoms aren’t obvious, the economic impact can be significant.

Let’s break down what causes these challenges, and how to stay ahead of them.

Why Early Lactation Challenges Matter

Calving may only take a few hours, but the weeks that follow can shape a cow’s entire lactation. The transition from dry cow to milk production is one of the most metabolically intense periods. If she stumbles here, whether from milk fever, ketosis or simply sluggish intake, it’s hard to recover that lost ground.

Even short-term metabolic stress can have long-term consequences such as:

• Reduced peak milk and persistency

• Increased culling risk

• Poor reproductive performance

• Higher susceptibility to other diseases (like mastitis or metritis)

Understanding the physiology behind milk fever and ketosis is the first step to improving transition outcomes. Prevention, not reaction, has to be the goal.

What is Milk Fever?

Despite the name, milk fever isn’t caused by a pathogen and doesn’t involve a fever. It’s the result of sudden hypocalcemia, low blood calcium, that occurs around calving when the cow begins lactating.

Blood calcium must stay above 7.5 mg/dL for muscles and nerves to function properly. But when lactation begins, calcium demand skyrockets. If the cow’s system isn’t ready to mobilize stored calcium from her bones, her blood calcium plummets and milk fever sets in.

Clinical signs of milk fever include:

• Muscle tremors

• Cold ears

• Incoordination or inability to stand

• A down cow with a tucked head and dull eyes

Clinical cases require immediate IV calcium treatment. But subclinical milk fever is far more common, and far more expensive.

Studies show up to 50% of older cows experience subclinical hypocalcemia after calving, reducing feed intake and opening the door to problems like ketosis, displaced abomasum and retained placenta.

The Hormonal Balancing Act

Calcium and phosphorus homeostasis is tightly regulated by a hormonal trio: parathyroid hormone (PTH), calcitonin and vitamin D. PTH mobilizes calcium from bone when blood levels fall, calcitonin encourages calcium storage and vitamin D supports absorption and bone turnover. But vitamin D must first be metabolized into its active form, 1,25-dihydroxycholecalciferol, via the kidney, using precursors from the diet or sunlight. (1)  

Because this hormonal interplay takes time, cows that enter lactation in a high-calcium state can’t mobilize calcium quickly enough. That’s why the greatest risk for milk fever falls within the first five days post-calving, when calcitonin is still active, but PTH hasn’t yet reached full function.

Why Low Calcium Diets Pre-Calving Work

Counterintuitively, feeding less calcium before calving is one of the most effective ways to prevent milk fever.

A low-calcium diet, about 80 g of calcium and 60 g of phosphorus per day for 30 days prepartum, stimulates PTH release before calving, “training” the cow to pull calcium from her bones.

Without this hormonal “priming,” a cow can’t respond quickly enough when lactation begins, leading to a dangerous lag in blood calcium.

This window of vulnerability, the first 5 days post-calving, is when most cases of milk fever develop. Feeding strategies that stimulate PTH before calving help close that gap and reduce the risk.

Pro Tip: Avoid feeding high-calcium forages like alfalfa in the close-up pen. Use straw, grass hay or low-calcium pre-fresh rations to control intake.

The Dehydration Factor: An Overlooked Complication

Many producers don’t realize just how much fluid a cow loses during calving, not only from delivering the calf itself, but also from the release of amniotic fluid, placental membranes, fetal urine and blood. A 100 lb. calf may be accompanied by 100+ lbs. of fluid losses. That’s equivalent to more than 10 gallons of water.

Post-calving dehydration can:

• Suppress appetite and water intake

• Slow the return to normal rumen function

• Delay feed transition to lactation rations

• Increase the risk of both milk fever and ketosis

If cows aren’t drinking or eating aggressively post-calving, they’re not recovering well and that slows the entire operation down.

What About Ketosis?

Where milk fever starts with calcium, ketosis starts with energy.

Ketosis occurs when the cow can’t eat enough to meet her energy needs. Her body responds by breaking down fat for fuel, but this releases ketones like beta-hydroxybutyrate and acetone, chemicals that suppress appetite and further reduce intake.

The result? A negative energy spiral.

High ketone levels dull appetite, creating a vicious cycle of low intake and worsening energy deficits. Ketosis often follows milk fever, but it can also result from simple feed deprivation. Subclinical cases are common and may only be detected with urine or milk tests.

Many cows with subclinical ketosis never show obvious signs, but they produce less milk, take longer to breed back and are more likely to be culled.

Natural Support When Fresh Cows Need it Most

Most fresh cow protocols already administer a calcium bolus immediately after calving, and while this can help elevate blood calcium temporarily, it doesn’t address the entire physiological challenge.

A bolus provides calcium directly, but without stimulating the hormonal mechanisms (especially PTH) that control calcium homeostasis, that calcium may not be retained or mobilized effectively in the days that follow. It also doesn’t correct dehydration, support microbial energy generation in the rumen or provide ongoing metabolic support during the five-day post-calving lag where PTH is still increasing and calcitonin is tapering off.

That’s why Ralco designed Start Strong™ for Fresh Cows to offer a more holistic, natural and research-based solution. It was designed to bridge the critical gap between calving and full metabolic recovery by addressing all three pillars of fresh cow vulnerability:

1. Milk Fever: Supporting Calcium Recovery and Retention

Start Strong helps maintain normal blood calcium levels, not just by providing minerals, but by supporting the cow’s ability to mobilize and utilize calcium efficiently. It supplies calcium, magnesium sodium and potassium in a balanced electrolyte blend that improves systemic absorption and helps maintain cellular function under metabolic stress.

By delivering calcium through an isotonic solution, Start Strong improves hydration and electrolyte movement across cell membranes which is critical for nerve conduction, muscle contraction and rumen motility. This helps cows avoid the muscle tremors, weakness and depression that’s often seen in both clinical and subclinical milk fever.

Importantly, by supporting normal hydration and rumen function, Start Strong also extends the cow’s ability to tolerate metabolic imbalance during the 5-day “calcitonin-to-PTH transition window,” buying valuable time until her natural hormonal response fully kicks in.

2. Ketosis: Breaking the Negative Energy Cycle

Ketosis often follows milk fever but can also occur independently when cows enter negative energy balance. Start Strong tackles ketosis on multiple metabolic fronts:

• Dextrose provides immediate, glucose-based energy to fuel early lactation.

• B-vitamins (niacin, riboflavin, thiamine) drive the Krebs cycle, supporting energy production in both cow and rumen microbes.

• Microbial Catalyst® technology, a patented cobalt source, increases rumen microbial activity, especially those fermenting fibrous feeds to produce more propionate – a volatile fatty acid (VFA) that’s readily converted into glucose in the liver for energy.

• Cobalt and vitamin B12 are essential cofactors in the metabolism of propionate through the gluconeogenic pathway, helping convert VFAs into usable blood sugar. Cobalt deficiency, in particular, has been linked to ketosis in dairy heifers. (1)

Together, these components help reverse energy deficits, reduce ketone formation and restore appetite in cows that are otherwise stuck in a downward spiral. When delivered quickly after calving, Start Strong helps stabilize metabolism and support consistent feed intake, both of which are essential to keeping ketosis at bay.

3. Dehydration: Rehydrating and Rebooting the System

Calving results in significant fluid loss through the calf, placenta, amniotic fluid and blood. As stated before, a 100-lb calf can represent a net loss of over 10 gallons of fluid. This natural dehydration suppresses appetite and slows the return to normal rumen function.

Start Strong helps counter this with a water-soluble, isotonic formula that delivers fluid, electrolytes and energy in one solution. It promotes osmotic balance, helps smooth muscle contraction and improves cow willingness to eat and drink after the stress of labor.

For cows that won’t drink voluntarily, the product can be delivered via oral drench. A second dose within 12–24 hours is often beneficial, especially in sluggish eaters or higher-risk, older cows.

More Than Just a Supplement, A Metabolic Safety Net

Start Strong is more than a supplement; it’s a fresh cow safety net. By supporting calcium balance, hydration and energy metabolism, it helps prevent metabolic setbacks that can quietly derail performance. It fills the gaps a calcium bolus can’t, offering real support when cows need it most.

One or two doses can help stabilize intake, speed recovery and set the tone for a stronger, more productive lactation.

When and How to Use Start Strong

Start Strong is water-soluble, palatable and easy to administer at calving:

• Mix one 1 lb. package in 5 gallons (20 liters) of clean, lukewarm water.

• Offer immediately after calving as a voluntary drink.

• If the cow refuses to drink, administer via oral drench to ensure full absorption.

• A second dose 12–24 hours later is optional for cows that are slow to eat or visibly struggling.

• If cows are eating well, Start Strong can also be added directly to feed, though water delivery is preferred to support hydration.

Ready to Help Your Fresh Cows Start Strong?

The first 24 hours after calving matter more than any other. Don’t wait to give your cows the metabolic support they need to thrive.

Contact your Ralco representative today or call our customer service team at 1-800-533-5306 to place your order or find a dealer near you!

Start Strong for Fresh Cows - Starter Pack for Fresh Cows

Start Strong for Fresh Cows is a natural performance pack for fresh cows that supports appetite and helps restore vital nutrients immediately after calving.

Learn More

References

1. Yates, D. (1990). In B. P. Smith (Ed.), Large Animal Internal Medicine. St. Louis: Mosby-Year Book.