Milk fever is a very costly metabolic disease in the dairy herd, costing on average between £200 to £300 for an uncomplicated case.

It is largely controlled by nutrition and ensuring the correct balance of major minerals in the dry cow ration. While there are various nutritional strategies that can be used for milk fever prevention during the dry period, management, housing, and environmental factors also play a role.

The recent introduction of a calcium binder product to close-up dry cows at SRUC’s three dairy herds at Dumfries has been a positive move, with a significant reduction in clinical milk fever cases.

Previously the nutritional strategy for milk fever control was a partial DCAB (dietary cation-anion balance) system using the anionic salt magnesium chloride. Even working with silage made from ground receiving little or no slurry, the milk fever incidence was still above the target of < 5% and was often running around 8%.

The calcium binder is a synthetic zeolite clay which binds to calcium in the gut, reducing its absorption so that it passes out through the faeces. This helps stimulates the cow to kickstart her own hormonal mechanisms to release calcium from bones, helping maintain blood calcium levels when demand greatly increases at the onset of lactation.

As calcium is also important for smooth muscle contraction, ensuring adequate blood calcium status also reduces the risk of slow calvings and retained foetal membranes (RFM). In addition, the product has been proven to increase feed intakes post-calving, with cows less likely to be in negative energy balance and experience metabolic issues in early lactation.

Initial results at SRUC’s three dairy herds over a five-month feeding period show that the calcium binder has worked exceptionally well (see following table), with only four cases of milk fever out of 325 calvings. The rates of milk fever, RFM and metritis are compared to the previous 12-month period when a partial DCAB diet was fed throughout the dry period.

Out of the four cases of milk fever that occurred during the last five months, one case was in a cow that calved early and had not yet received the binder. Two other cases were explained by a short period of inaccurate feeding with the mixer wagon, which was quickly rectified, proving that if fed properly the binder does its job.

While all the dry cows receive the same diet, the far-off groups are housed separately on cubicles and the close-up groups are housed on straw for the last three weeks of gestation. The calcium binder for the close-up cows (fed at 500g/cow/day) is added to the mixer wagon once the far-off cows have been fed out.

The mineral content of the diet is still important to balance through mineral supplementation but the calcium and potassium levels in the forages are much less of a concern and should not affect how the product works. However, it is still important to maintain a magnesium content of 0.4-0.45% in the dry matter and not to oversupply phosphorus, which can induce milk fever at high levels.

While the product has proven to have reduced the incidence of milk fever dramatically, it is an added cost (at just over £32.55/cow for 21 days) and the decision was taken to feed the binder for the last two weeks of the dry period from mid-December onwards.

As well as a cost saving the other benefit was that cows were moved to the straw pen one week later, meaning that during times when there were more calvings, these cows had more space in this close-up pen, while the cubicle accommodation had capacity to house more of the far-off cows for an extra week.

It is crucial that as soon as the cow has calved, she does not have access to the dry cow diet containing the binder, as this will induce milk fever.

Once calved, the milking ration should be offered as soon as possible for the cow to achieve a high calcium intake. This may be a useful product to try if other strategies for milk fever control are struggling to keep milk fever rates below 5%.