Keeping tabs on ketosis risk during transition

As vets, we play an important role in supporting farmers to run a good transition management strategy within their day-to-day running of the herd.

It is possible to limit transition diseases by carefully managing the period from 60 days pre-calving to 30 days post-calving, using herd health data to inform management decisions and help minimise the risk of ketosis and milk fever.

Although some clear guidelines exist for space allowances and intake targets, successful transition management should involve a farmer-vet discussion to balance the science with what is best for the cow in the facilities available.

Alongside disease and sub-performance, the incidence of ketosis will have a significant negative impact on a cow’s reproductive health. For example, a case of ketosis could delay a cow’s return to cyclicity, reducing first service conception rates or delaying first service.

So, bearing in mind these risk factors, transition cows need careful management to minimise the potential of long-term health and fertility issues.

Informed decisions

A well-run fresh cow monitoring programme is incredibly valuable to flag animals that are at higher risk of ketosis.

Through the use of tools such as specific software that captures cow health, fertility and milk production data, you can work with farmers to identify cows that pose a higher risk of ketosis, and work out targeted management plans for each individual.

Risk factors for ketosis include a history of high body condition score (BCS) of more than 3.5, longer lactation periods, lameness issues, twin-bearing or older cows. This needs to be known at least a month pre-calving, so adjustments can be factored into the farm’s transition management plan to prevent problems. Solutions for high-risk cows could include administering a monensin bolus three to four weeks pre-calving to help close the “energy gap” that leads to ketosis, drying them off earlier or moving them to the transition pen sooner. Value also exists in giving staff an awareness of what a high-risk cow looks like.

Milk fever control in the transition diet is a key consideration, with the ultimate aim being to help cows mobilise calcium more effectively around the point of calving. This can be achieved through calcium restriction, partial or full dietary cation-anion balance diets, or using a calcium binder.

The most suitable option depends on individual farm factors, such as availability of forages, group sizes, yield expectations and facilities. Vets can also help farmers to assess diet suitability by undertaking mineral assessments, to ensure cows are provided with adequate vitamin D and E, and selenium to support the immune system. In the final seven days of pregnancy, blood sampling can be carried out to assess non-esterified fatty acid (NEFA) levels, which are a measure of body fat mobilisation.

Elevated NEFA levels in the seven days pre-calving are associated with cows carrying too much body condition or not achieving adequate dry matter intakes pre-calving – both key risk factors for ketosis.

We also need to be able to assess cow intakes, by working with the farmer to monitor residual feed left, using farm data, and through assessment of the cow looking at metrics such as rumen fill.

Preventing long-term issues

Post-calving, it is vital to monitor the freshly calved group, as the risk of disease is highest during the first two weeks post-partum. Cows flagged as high risk should be paid particular attention to.

At this point, farmer-led ketone testing is another important point to assess cow transition and take immediate action if needed. If facilities allow post-calving, cows will go into a group designed for fresh animals for at least 28 days. The ration should be the same as the main milking ration, but the facilities in terms of bed allowances and feed space should be increased for these fresh cows, to allow better access to feed and optimal cow comfort.

During the first week post-calving, we want to capture accurate records for each cow, such as cases of retained foetal membrane, metritis or milk fever, assisted calving or the event of twins, and BCS.

We can gather data to establish any trends, such as patterns of cows that are transitioning well or otherwise.

Longer term, monitoring of the presence of a corpus luteum at post-natal check or first service conception rate is a good indicator of transition success.

Generally, cows with delayed first service or poor first service conception rates end up gaining excessive body condition at the end of lactation, so could be at risk of having prolonged lactations or carrying additional body fat, and the poor transition cycle is perpetuated.

Feeding these data insights back to the farmer is crucial to help inform transition planning and advise them on appropriate adjustments for herd management.