What is milk fever in cows?
Milk fever in cows is a metabolic disease caused by a low blood calcium level (hypocalcaemia). It occurs close to or just after calving. Between 3% and 10% of cows are affected each year, with much higher percentages occurring on some farms. About 80% of milk fever occurs within one day of calving.
What are the symptoms of milk fever in cows?
- Loss of appetite
- Excitability and nervousness
- Weakness, weight shifting, and shuffling of the hind feet
What are the causes of milk fever in cows?
- Age: The risk of milk fever increases by approximately 9% per lactation
- Higher yielding cows are more susceptible to milk fever
- Breed: Jersey cows are more susceptible than Holstein cows
- High levels of potassium or sodium inhibit calcium mobilization from the bones
- Low magnesium level in a diet, reduced calcium absorption in the gut
- Reduced intake (high mycotoxin levels in the diet)
- High estrogen level around calving inhibits calcium mobilization
- High calcium intake during dry periods reduces the ability for Ca utilization from other sources
- Reduced roughage in the diet
What are the problems of milk fever in cows?
There are 2 forms of Milk Fever in cows – Clinical and Subclinical Clinical.
- Milk fever in cows presents as a cow is unable to stand, and she will feel cold to the touch.
- Subclinical Milk fever in cows presents differently and is more common. The cow will be able to stand, but she will be weak, nervous and will perform less efficiently.
- Both conditions will lead to a host of other issues on the farm including; slow & difficult calving, retained placenta/cleanings, mastitis, displaced abomasum, fatty liver syndrome, ketosis, reduced milk yield (up to 1000L per cow), metritis, secondary injuries to bones, nerves or muscles, and reduced heats and conception.
- Studies have shown that the annual cost of milk fever can be greater than €6,000 in a 100-cow herd.
Milk Fever in Cows – Solutions
Management of the cow’s Body Condition Score (BCS) is crucial, as fat cows are 4 x more likely to develop milk fever.
- Ensuring the cow has adequate levels of calcium in the blood pre-calving, as a large amount of calcium is required for the increased bone growth in the unborn calf and the production of colostrum.
- Increasing the level of magnesium in the diet will help with mobilizing calcium from their bones.
- Increasing dietary Mg from 0.3 to 0.4% of your cows’ total diet reduces milk fever risk by approximately 62%.
- Proper attention to dietary anion strength is also important to help reduce the risk of milk fever in cows.
- Dietary Cation-Anion Difference formulations or DCAD diets balance four macrominerals: the anions chloride and sulphur; and the cations sodium and potassium. Getting this balance right leads to better calcium uptake.
We recommend feeding magnesium chloride to improve calving, increase herd health and reduce labour during the calving period.