TheDairySite.com - news, features, articles and disease information for the dairy industry

Featured Articles

Subclinical Ketosis is Talking Point at World Congress

30 September 2012

Companion Consultancy

Hundreds of cattle vets from around the world gathered in Lisbon this June to hear the latest research on cattle disease at the World Buiatrics Congress. While fertility, parasite control and disease management were understandably major topics at the event, it was a metabolic disease that had all the delegates sitting up and taking notice, writes Susan McKay, Companion Consultancy.

New findings on ketosis and particularly subclinical ketosis indicate that this disease may be much more important than vets or farmers had previously thought – with 30% of cows affected in the first 50 days of lactation. It is realistic to expect this disease to become much higher profile in herd health plans in the future and developing an effective strategy to deal with the condition should have very positive benefits for farmers.

Energy Balance

Dairy cows have been selected over the years for their ability to divert nutrients to support milk production. This means that all cows will experience weight loss and negative energy balance around calving. A reduced energy intake around the time of transition – just before and after calving – results in an overall negative energy balance. When fat stores are mobilised (as NEFAs – or free fatty acids), ketones can be produced. This effect is more marked in overconditioned cows. Ketotic cows will often be off food, depressed and may develop a range of signs such as incoordination and behavioural changes.

The Scale of Subclinical Ketosis

An extensive survey of blood samples from 43,000 cows in 1,200 dairy farms across the UK suggests that although clinical ketosis is rare, affecting only 1.4% of samples, subclinical ketosis is common. Over half of all dry cows within 10 days of calving were diagnosed with subclinical ketosis based on their blood results.

Of cows calved within the last 10-20 days, 27% had subclinical ketosis. This is important because these are not cows at peak lactation experiencing demands due to milk production; the issue here is reduced feed intake at a time of significant energy requirements, pushing the cow into a state of negative energy balance. The research team found the effects were most marked April through to September when cows were at grass.

The Consequences of Subclinical Ketosis

With all subclinical conditions, the challenge is that the condition is often a “hidden” problem with no clear visible symptoms. Whilst subclinical (“hidden) ketosis itself has no obvious signs, it is associated with a range of other clinical conditions: displaced abomasum, metritis, mastitis and a prolonged time in returning to oestrus. A study of 170 herds across Europe reported at congress found elevated BHB (ketone) levels in healthy cattle in the first two weeks post calving was associated with an increased risk of metritis, mastitis, displaced abomasums and also lameness.

Other speakers quoted figures of a 4-8 times increased risk of displaced abomasum and a three-fold increase in the risk of metritis. Cows experiencing a greater negative energy balance are around 80% more likely to suffer retained placenta. Raised BHB levels can also result in milk yield reduced by more than 300 Kg over the course of a cow’s lactation.

Adipose tissue (fat stores) is known to be metabolically active and can produce chemical messengers that promote inflammation. It is thought that inflammation could play an important role in the development of metritis and that the condition is not simply due to bacterial infection alone. Cows with metritis tend to have a lower feed intake than unaffected cows in the two weeks before calving and are therefore more likely to experience negative energy balance.

In terms of cows with subclinical ketosis returning to oestrus, delays of up to 130 days have been reported in cases of subclinical ketosis, compared to 108 days in cows without ketosis.

In addition to their poor metabolic status, cows with ketosis and subclinical ketosis will have reduced levels of insulin and other hormones needed to trigger development in the ovary at the point when fertility needs to be maximised. This clearly results in significant economic loss.

Subclinical is Costly

Subclinical disease always tends to be costly, often because it goes undetected. When costs are not immediately apparent or attributed, they are often unaddressed. Farmers may even be benchmarking their current performance against a record that has already been blighted by subclinical disease for some time.

A poster presentation by dairy farm management consultant Dick Esselmont, estimated the cost of subclinical ketosis could be as high as £683 per affected cow, based on culling rates, prolonged calving intervals, fatalities, costs of diseases associated with subclinical ketosis and direct milk loss. If that’s 30 cows in a 100 cow herd, then that’s a loss of over £20,000. And that’s for the ‘average’ herd.

Make a Difference

As ketosis becomes higher profile farmers can expect their vets to be increasingly likely to talk about control strategies. If it seems likely that subclinical disease could be an issue in your herd, ask about NEFA and BHB testing. Refining the technique for body condition scoring and benchmarking the herd against targets at key stages (drying off, calving, breeding and through lactation) is a useful intervention. The aim is to calf down at body condition score 3-3.25. High yielding cows may be better able to tolerate higher scores – up to a maximum of 3.5.

Allow adequate trough space and ensure the feeding strategy is right with regard to what and how much is fed. Ensure your vet has data from nutritionists or feed advisors used on the farm and is given the opportunity to look at the clinical picture together with any other relevant information to allow them to make an appropriate recommendation. Subclinical ketosis doesn’t have to remain a hidden disease and is unlikely to do so following presentation of the findings at the congress. Knowledge is, of course, power and dealing with subclinical ketosis could make a big impact on the productivity and profitability of dairy farms.

References

1 . Macrae I A, Burrough E, Forrest J (2012) Prevalence of clinical and subclinical ketosis in UK dairy herds: 2006-2011, Oral communication, XXVII World Buiatrics Congress 2012

2. Suthar V, Canelas Raposo J, Deniz A, Heuwieser W (2012) Subclinical ketosis and relationships with post partum diseases in European dairy cows, Oral communication, XXVII World Buiatrics Congress 2012

3. LeBlanc S (2012) Integrating metabolic and reproductive health in dairy cows, Keynote lecture, XXVII World Buiatrics Congress 2012

4. Esselmont D (2012) The cost of ketosis in dairy cows, Poster presentation, XXVII World Buiatrics Congress 2012

5. Mulligan F (2012) A Herd health approach to dairy cow nutrition and production diseases of the transition and early lactation dairy cow, Keynote lecture, XXVII World Buiatrics Congress 2012

September 2012

Partners


Seasonal Picks

Managing Pig Health: A Reference for the Farm - 2nd Edition