Acétonémie de la vache laitière :Prophylaxis, Detection and Treatments

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Ketosis or acetonaemia is a metabolic disorder, characterized by an elevated level of ketone bodies in the blood. Although often asymptomatic, it can have significant consequences on the performance of livestock.

Description and possible causes

General description

In ruminant breeding, ketosis mainly appears in the early lactation period, when nutritional needs are high.

In cattle, the end of gestation is characterized by an increase in energy requirements and a decrease in intake capacity, as the rumen is compressed by the fetus. Calving and the resulting milk production cause a sudden increase in energy needs. The cows' intake capacity recovers slowly (it takes about a month to return to normal): during this period, the animal must draw on its fat reserves to meet its needs.

From a metabolic perspective, the energy used by a cow after calving mainly comes from fatty acids. These are normally broken down by the liver into glucose or ketone bodies which provide energy to tissues. However, sometimes the liver is overloaded with fatty acids, and their breakdown is incomplete: ketone bodies then accumulate in the blood (notably BHB: Beta-Hydroxy Butyrate). The cow is then energy deficient: this is ketosis.

Causes

This glucose deficiency is almost always synonymous with liver dysfunction or inappropriate feeding.

Three types of ketosis are distinguished :

• "Lean cow" syndrome: for undernourished animals, dietary energy intake is insufficient relative to needs.
• "Fat cow" syndrome: for animals with large fat reserves (body condition score > 4) after calving.
• Nutritional ketosis: due to ingestion of ketogenic or butyric acid-rich feeds (often poorly preserved silage).

Detection of clinical and subclinical cases

Clinical cases

The most severe cases, called clinical, can be detected by simple observation of symptoms:

• Weight loss of the animal
• Drop in milk production
• Lethargy or staggering
• Loss of appetite
• Characteristic acetone odor ("apple reinette") in the breath, milk, or urine of the animal

Subclinical cases

Conversely, subclinical cases include all asymptomatic forms that are difficult to detect visually. It is then necessary to use tests (for example the Ceto TEST, see below), which analyze the ketone body levels in milk, blood, or urine of animals to identify sick cows. Some of these tests are complemented by an analysis of milk fat (TB) and protein (TP) content: it is often considered that too high fat concentration and too low protein concentration (TB/TP ratio > 1.40) indicate a risk of ketosis.

Prevalence of cases: the example of Brittany

A common pathology

Some studies have observed a high prevalence of this pathology in dairy herds. In Brittany, a study was conducted using the indicator "Ceto TEST", on more than 1,250,000 milk samples showing the following results for 2013 - 2014:

On average, 4 to 5 subclinical cases per 1 clinical case are observed, so its presence can be difficult for farmers to detect.

Distribution of different forms of ketosis by severity within Breton herds. Eylips 2013-2014.

In more than half of Breton herds, a risk of ketosis was detected for at least 25% of the herd, with disparities among herds. A quarter of herds have more than 40% of freshly calved cows with ketosis.

Sensitivity factors

There are a number of factors, other than feeding or animal health status, that can make an animal more prone to ketosis. The study notably highlighted the impact of lactation number, and breed, which can imply a certain susceptibility or resilience to this pathology.

Ketosis cases, as a percentage of tested cows, by lactation number.

Ketosis cases, as a percentage of tested cows, by breed.

It is noted that primiparous cows, as well as the Normande and Montbéliarde breeds, are less prone to ketosis.

Consequences at the herd level

Even for subclinical cases, ketosis causes consequences on various animal performances. This impact was quantified via the study on the Breton herd, presented above.

Drop in milk production

According to the score obtained on the "Ceto TEST" indicator (0 = healthy animal; 1 & 2 = subclinical case; 3 - 4 - 5 = clinical case), the average daily production is strongly affected. For the most severe cases, it can be reduced by more than 5 kg per day on average.

Average daily milk production of a cow in Brittany, according to the score obtained on the "Ceto TEST" indicator. Eilyps, 2014.

Weakened immune system

This second consequence, more difficult to measure, is caused by the energy deficit of cows. Ketosis can thus promote the onset of other diseases such as retained placenta, metritis, mastitis, lameness, or return to heat problems. From an economic perspective, this impact can notably be measured via somatic cell count in milk, which can lead to penalties if too high:

Percentage of cows with somatic cell count above 300,000 cells/mL of milk, according to the score obtained on the "Ceto TEST" indicator. Study on the Breton herd, Eilyps, 2014.

Clinical ketosis is estimated to cause an average economic loss of €250 per cow.

Curative treatments

When ketosis cases are identified via tests or following symptom appearance, it is possible to provide treatments to stimulate glucose production and thus restore the energy balance of the affected animals.

For this, administration of Mono Propylene Glycol (MPG)' or Sodium Propionate directly orally, or injections of energy solutions intravenously, is recommended.

Preventive measures

To prevent the onset of ketosis in the herd, a series of preventive measures should be adopted.

• Concentrate the ration in energy at the end of gestation to meet needs
• Ensure good dietary transitions
• Avoid overconditioning of cows at the end of lactation
• Provide targeted MPG supplementation, before and after calving for "at risk" cows

For further information

Consult the EILYPS website, a consulting and expertise company in breeding:

https://www.eilyps.fr/sante/prevention-sante-troupeau/acetonemie/

Summary infographic

Ketosis in dairy cows infographic: prophylaxis, detection, and treatments

References

Cette page a été rédigée en partenariat avec Breeder Connect