She Went Down and Can't Get Up, and Despite the Name, There's No Fever
Milk fever (also called parturient paresis or hypocalcemia) is a metabolic disorder that hits when blood calcium levels drop too low around the time of calving. Despite the name, affected cows actually have normal or low temperatures. This condition can go from subtle weakness to life-threatening collapse within hours if you don't catch it and treat it fast.
This guide covers the physiology behind milk fever, how to recognize it, emergency treatment, and prevention strategies.
Understanding Milk Fever
What Is Happening
Colostrum contains 2-3 times more calcium than regular milk. A cow producing 10 liters of colostrum loses about 23 grams of calcium, while her blood contains only about 3 grams total. She must rapidly mobilize calcium from bones and increase gut absorption to keep up. If those adaptation mechanisms are too slow, blood calcium drops to dangerous levels.
When It Occurs
The highest risk period is the first 12-24 hours after calving, during the initial milk let-down. Milk fever can occur up to 48-72 hours post-calving and occasionally strikes just before calving, but it is rare more than 3 days after delivery.
Risk Factors
Age and Production
| Factor | Risk Level | Why |
|---|---|---|
| Older cows (5+ lactations) | High | Decreased bone mobilization efficiency |
| High milk producers | High | Greater calcium demand |
| First-calf heifers | Low | Lower milk production |
| Second-calf cows | Moderate | Increasing production |
| Jersey/Guernsey | Higher | High milk fat content |
| Beef cattle | Lower | Lower milk production |
Management Factors
| Factor | How It Increases Risk |
|---|---|
| High calcium diet pre-calving | Suppresses mobilization mechanisms |
| Excessive body condition | Higher milk production, reduced mobility |
| Poor body condition | Depleted calcium reserves |
| Lack of exercise | Reduced bone responsiveness |
| Vitamin D deficiency | Impaired calcium absorption |
| Magnesium deficiency | Impairs PTH function |
| Previous milk fever | 50% will have it again |
Environmental Factors
Hot weather causes stress and reduced intake. Cold weather increases energy demands. Transport stress and any other stressors around calving also contribute to the problem.
Recognizing Milk Fever
Stage 1: Early (Often Missed)
Stage 1 is easy to miss because the signs are subtle: shuffling feet, stiff gait, fine muscle tremors (twitching), decreased appetite, reluctance to move, and reduced rumen contractions. If you catch it here, treatment is simpler and outcomes are better.
Stage 2: Progressive
This is when most cases are identified. The cow goes down and can't get up despite trying. She may show a characteristic "S-shaped" kink in her neck, cold ears and extremities, dry muzzle, dilated pupils, subnormal temperature (below 101 F), weak pulse, decreased heart sounds, constipation, and depression. The classic description is a cow found sternal (sitting up on her chest) but unable to rise.
Stage 3: Critical
Stage 3 is a true emergency. The cow is unresponsive or comatose, bloat may be developing, pulse is very weak, heart rate is increased above 100 bpm, extremities are cold, and muscles are flaccid. Without immediate treatment, Stage 3 milk fever is fatal.
The Classic Presentation
"Found her this morning, down and can't get up. She's alert but won't rise. Her ears are cold and her nose is dry."
This describes typical Stage 2 milk fever requiring immediate treatment.
Treatment
Emergency Treatment Protocol
Treatment for milk fever centers on getting calcium back into the cow's bloodstream as quickly and safely as possible. The route of administration depends on the severity of the case.
Intravenous Calcium (Preferred for Severe Cases)
To administer IV calcium, warm the solution to body temperature, clean the skin over the jugular vein, insert a 14-16 gauge needle into the jugular, attach the IV line and bottle, and administer SLOWLY over 10-15 minutes. Monitoring during administration is critical: listen to the heart throughout, and if it becomes irregular, STOP immediately. Wait for the heart to stabilize before continuing. Warming the solution slightly reduces cardiac stress.
Signs of response include belching, urination, defecation, muscle tremors, and attempts to rise. Most cows are up within 1-2 hours of successful treatment.
Subcutaneous Calcium
Subcutaneous calcium is administered at multiple sites (2-3 locations), typically under the skin of the neck or behind the shoulder, 50-100 mL per site. Massage the area to distribute the fluid. The advantage is that inexperienced handlers can give it and it provides sustained release. The disadvantage is that it may not work in severe cases and can cause tissue irritation.
Oral Calcium Supplements
Oral calcium products include calcium chloride gels and pastes, calcium propionate, and commercial oral calcium supplements. These work well as follow-up after IV treatment or for mild, early-stage cases.
Post-Treatment Care
After treatment, prop the cow in sternal position if she's still down, provide comfortable bedding, offer water when alert, and monitor for 24-48 hours since relapse is common. Consider follow-up calcium supplementation and watch for secondary complications. Relapses typically occur within 24-48 hours; retreat as needed and consider slow-release calcium methods.
When to Call the Veterinarian
Situations Requiring Veterinary Help
Call your veterinarian for Stage 3 (comatose) milk fever, no response to treatment, repeated relapses, uncertain diagnosis, complications developing, or if IV treatment is not something you're comfortable doing.
What Veterinarian May Do
Your vet can confirm the diagnosis, administer IV calcium with proper monitoring equipment, address concurrent problems (ketosis, metritis), recommend prevention for the future, and assess for downer cow syndrome if the cow isn't recovering.
Complications and Associated Conditions
Down Cow Syndrome
If a cow treated for milk fever doesn't rise within a reasonable time, other conditions may coexist. Down cow syndrome requires intensive nursing care, including rolling her side to side every few hours to prevent muscle damage.
Associated Conditions
Milk fever often occurs with or predisposes the cow to other problems.
| Condition | Relationship |
|---|---|
| Ketosis | Energy deficit, both metabolic disorders |
| Retained placenta | Low calcium impairs uterine contraction |
| Metritis | Immunosuppression, retained placenta |
| Displaced abomasum | Reduced gut motility |
| Mastitis | Immunosuppression |
| Dystocia | Weak uterine contractions |
Prevention Strategies
Dietary Management Pre-Calving
A high-calcium diet before calving is actually counterproductive. The cow's body doesn't activate calcium mobilization mechanisms, leaving her unprepared for the sudden demand at calving. A low-calcium or controlled diet in the weeks before calving forces the body to activate those mechanisms, so the cow is "primed" and ready to handle the calcium drain when milk production begins.
Dietary Cation-Anion Difference (DCAD)
The balance of certain minerals in the diet affects blood pH, and slightly acidic blood improves calcium mobilization. "Anionic" diets lower blood pH through products like magnesium sulfate, calcium chloride (which also provides calcium), and commercial anionic mineral mixes. Monitor effectiveness by checking urine pH: the target is 6.0-7.0 in beef cattle and 5.5-6.0 in dairy, which indicates adequate acidification.
Oral Calcium at Calving
Administering oral calcium at calving and repeating 12-24 hours later provides readily available calcium during the critical period and can prevent subclinical cases from becoming clinical. Products include calcium chloride (effective but can irritate), calcium propionate (safer, also provides energy), and commercial calcium boluses or pastes.
Vitamin D Supplementation
Vitamin D increases calcium absorption, but timing is critical because giving it too early can cause rebound hypocalcemia. Consult your veterinarian for the right protocol for your operation.
Other Prevention Measures
Adequate exercise through outdoor access, reduced stress around calving, identification and monitoring of high-risk cows, and ensuring adequate magnesium intake all contribute to preventing milk fever.
Prevention Protocol Summary
For High-Risk Herds (Dairy, Older Cows)
| Timing | Action |
|---|---|
| Dry period | Low-calcium or anionic diet |
| Last 2-3 weeks | Anionic minerals, monitor urine pH |
| At calving | Oral calcium supplement |
| 12-24 hours post | Second oral calcium dose |
| Monitor | Watch for early signs 72 hours |
For Lower-Risk Operations (Beef)
| Timing | Action |
|---|---|
| Pre-calving | Avoid high-calcium mineral |
| At calving | Oral calcium if high risk cow |
| Post-calving | Monitor, especially older cows |
Subclinical Hypocalcemia
The Hidden Problem
Subclinical hypocalcemia affects a significant percentage of cows without showing dramatic signs. The incidence is likely higher than recognized in beef herds. The effects are real: decreased dry matter intake, higher risk of other diseases, reduced fertility, and lower milk production.
Detecting Subclinical Cases
Watch for reduced appetite, lower milk production than expected, and a higher incidence of other problems in fresh cows. These subtle clues may point to subclinical hypocalcemia across the herd.
Managing Subclinical Risk
Implement prevention protocols for all at-risk cows rather than waiting for clinical signs. Consider routine oral calcium supplementation at calving for older or higher-producing females.
Beef Cattle Considerations
Lower Incidence but Still Occurs
Beef cattle generally have lower milk fever incidence because of lower milk production, and they spend more time at pasture (providing exercise and sun exposure for Vitamin D). Higher-risk beef animals include older cows (8+), thin cows, and cows on high-calcium pastures or hay.
Beef-Specific Management
Know which cows in your herd have a history of milk fever, since 50% will have it again. Monitor older, heavier-milking cows during the calving period, have treatment supplies on hand before the season starts, and consider oral calcium for at-risk individuals.
Treatment Supplies to Stock
Basic Kit
- Calcium gluconate or calcium borogluconate (2-3 bottles)
- IV administration set
- 14-16 gauge needles
- Stethoscope (to monitor heart)
- Oral calcium supplement (gel or paste)
- Thermometer
- Veterinarian contact info
Notes on Storage
Store calcium products at room temperature, check expiration dates before each calving season, protect from freezing, and have fresh supplies on hand.
Key Points Summary
| Stage | Signs | Treatment | Urgency |
|---|---|---|---|
| 1 | Mild excitement, tremors, stiff | Oral calcium, close monitoring | High |
| 2 | Down but sternal, cold ears, "S" neck | IV calcium (slow), follow with oral | Urgent |
| 3 | Flat, comatose, bloating | IV calcium immediately, call vet | Emergency |
The Bottom Line on Milk Fever
Milk fever is preventable and treatable, but it takes knowing the risk factors, catching the signs early, and treating fast. For operations with recurring problems, prevention through dietary management works better than treating individual cases. Have supplies on hand, know the signs, and act quickly when you suspect milk fever.
Related Resources
- Post-Calving Cow Care
- Uterine Prolapse Emergency
- Preparing for Calving Season
- Retained Placenta Management
References
- Goff, J.P. "The monitoring, prevention, and treatment of milk fever and subclinical hypocalcemia in dairy cows." The Veterinary Journal.
- Reinhardt, T.A., et al. "Prevalence of subclinical hypocalcemia in dairy herds." The Veterinary Journal.
- University of Wisconsin-Madison. "Milk Fever in Dairy Cattle." vetmed.wisc.edu
- Oetzel, G.R. "Management of dry cows for the prevention of milk fever." Veterinary Clinics of North America: Food Animal Practice.
- Texas A&M AgriLife Extension. "Metabolic Problems at Calving." agrilifeextension.tamu.edu
- DeGaris, P.J., Lean, I.J. "Milk fever in dairy cows: A review of pathophysiology and control principles." The Veterinary Journal.
