Treating cases of Milk Fever Correctly

In this article we cover:

• Recap of milk fever basics and what to look for

• IV calcium - when to give it and what are the risks

• The other stuff in those bags... Mag, Phosphorus, Glucose, do you really need them???

• Our recommended treatment protocol

Milk Fever Basics

Milk fever is a metabolic disorder in cows caused by a lack of calcium (hypocalcaemia), which most commonly occurs around calving time.

Cows suffering from clinical milk fever typically progress through 3 stages.  

Stage I clinical milk fever. Clinical signs may include wobbliness, weight-shifting, dull appearance, cold extremities, hypothermia, not eating and reduced ruminal contractions.

Oral calcium, either in the form of a transition bolus or an oral drench, is the preferred supplementation choice for Stage 1 clinical milk fever. Oral calcium supplementation causes a very rapid spike in blood calcium concentrations that peak within about 30 minutes of administration. Intravenous calcium is not recommended for standing cows.  

Stage II milk fever can last from 1 to 12 hours. The animal appears dull and listless; she has cold ears and a dry nose; she will likely be unable to stand, usually found lying in sternal recumbency. The affected animal may turn its head into its flank or may extend its head. Cows often have a characteristic “S-bend” in the neck. Constipation and a decrease in body temperature are also common.

Stage III milk fever is characterized by the animal's inability to stay sitting up, the cow lays out flat, often bloated and a progressive loss of consciousness leads to a coma. Cows in stage III will not survive for more than a few hours without treatment.

IV Calcium

Intravenous calcium

• Is clearly necessary for cows with Stage 2 or Stage 3 milk fever because recumbent cows can quickly suffer irreversible musculoskeletal damage.

• The goal of IV calcium treatment should be to provide as little calcium as possible in order to get the cow up. Any IV calcium beyond the minimum required exposes the cow to additional risk for fatal cardiac complications, inhibits the cow’s own attempts at calcium homeostasis, and increases the risk for a hypocalcaemia relapse (those annoying cows that get up but go down again in a few hours).

• It is not possible to precisely determine the optimal dose of IV calcium for recumbent cases of milk fever. Based physiological calculations and clinical studies, a best guess would be 8-10grams of calcium IV.

• A single bag of calcium for IV infusion provides about 8 to 14 grams of calcium – an amount that replaces more than the cow’s entire body deficit of calcium in almost all scenarios. Providing some calcium beyond the deficit is reasonable because calcium will continue to be lost in the colostrum.                                                                                                                 

 Risks Associated with IV Calcium Treatments.

• IV calcium infusion increases blood calcium to extremely high and potentially dangerous concentrations that puts cows dangerously close to a fatal heart arrhythmia.

• Hypercalcemia following IV treatment directly suppresses parathyroid hormone (PTH) secretion. PTH secretion is the cow’s primary response to low calcium levels. PTH enhances reabsorption of calcium from the kidneys and bone, and stimulates the production of vitamin D. 

• Hypercalcemia caused by IV calcium also stimulates the release of the hormone calcitonin (CT). CT actively inhibits calcium resorption from the kidneys and bone.

• A rebound hypocalcaemia following IV calcium administration is caused by the combined effects of impaired PTH secretion and increased CT secretion. Cows given IV calcium typically return to hypocalcaemia within about 8 hours and remain hypocalcaemia until 24 to 48 hours after IV treatment.

 Do you need all the “other stuff”? 

• Many products marketed for treatment of milk fever include phosphorus, magnesium, and glucose/dextrose in addition to calcium. None of these additional electrolytes are necessary, and some could be harmful.

• Cows suffering from clinical milk fever typically have low blood phosphorus, high blood glucose and either high or low blood magnesium.

• Low blood phosphorus typically follows hypocalcaemia; however, it does not require treatment unless it persists following the correction of the hypocalcemia.

• The phosphorus source in metabolic solutions is typically hypophosphite, this form of phosphorus is not biologically available to the cow.

• Administering additional magnesium to hypocalcaemia cows is not necessary; however, there is no evidence of physiological basis for it to be harmful.

 Follow up treatment for cows with milk fever.

• Oral calcium supplementation is the preferred method of preventing hypocalcaemia relapses following successful IV calcium treatment. We recommend administering one oral transition bolus following treatment with an IV bag, followed by a second bolus about 12 hours later.

• Subcutaneous calcium administration is a second-choice approach, it does reduce the risk for a clinical relapse by about half compared to cows not given any source of slower-release calcium after IV administration, but the effect only lasts around 6 hours.

Follow up treatment for cows with milk fever.

Oral calcium supplementation is the preferred method of preventing hypocalcaemia relapses following successful IV calcium treatment. We recommend administering one oral transition bolus following treatment with an IV bag, followed by a second bolus about 12 hours later.

Subcutaneous calcium administration is a second-choice approach, it does reduce the risk for a clinical relapse by about half compared to cows not given any source of slower-release calcium after IV administration, but the effect only lasts around 6 hours.

The Farm Vets Milk Fever Treatment Recommendation

For cows with clinical milk fever (Stage II & III) give the following:

• 1 bag IV of metabolic solution containing just calcium OR calcium + magnesium

• 1 Transition bolus OR if swallowing 1 x oral drench of a calcium containing product

• Repeat the oral dose after 12 hours.

• An injection of anti-inflammatory such as ketomax to the cow to help reduce prolonged recumbency due to inflammation and painful muscles

The transition period (2 weeks before to 6 weeks after calving) is the most important time for a dairy cow, with management during this period aimed at minimising the risk of metabolic problems like milk fever. The best method of preventing subclinical and clinical milk fever is to supplement cows with correct amount of magnesium pre-calving and then to supplement with calcium (limeflour) in the COLOSTRUM and EARLY lactation period.