Nearly one-third of newly-calved cows could be suffering from a state of subclinical ketosis, making them more than two-and-half times more likely to get a displaced abomasum.
According to results from a pan-European audit, 30% of UK cows have “hidden” ketosis, caused by a poor adaptive response to negative energy balance. These cows are not only more likely to develop clinical ketosis, but are also at greater risk of clinical cases of other metabolic and reproductive disorders such as retained placenta, displaced abomasum and milk fever.
Mike Steele, technical consultant for Elanco, which commissioned the study, says: “Ketosis occurs if the rate of fat mobilisation is too fast for the cow’s liver to oxidise it to energy. Ketones such as BHBA then build up in the blood. When blood BHBA levels exceed 1,000-1,400mol/litre, it results in subclinical ketosis. “
Between July 2011 and January 2012, 2,489 cows in 74 herds were tested across five European countries – Germany, Italy, France, UK and the Netherlands. The UK farm audit tested 763 cows from 15 dairy herds, with results showing an incidence of ketosis varying from 10-60%.
The study found the health and performance consequences of subclinical ketosis were wide-ranging. Positive animals were:
- 1.7 times more likely to have had a difficult calving;
- 2.2 times more likely to have had a retained placenta;
- 1.8 times more likely to have had milk fever;
- 4.5 times more likely to have had gastro-intestinal distress;
- 2.3 times more likely to get mastitis;
- 2.7 times more likely to get a displaced abomasum;
- 11.5 times more likely to get clinical ketosis; and there was also a slight but significant trend to an increased susceptibility to metritis.
“Clinical ketosis was diagnosed in 1% of the cows surveyed in the main audit. It highlights that while clinical cases of ketosis are rare, these cases are just the tip of the iceberg and a much larger number of animals will be experiencing subclinical levels of ketosis,” says Mr Steele.
He recommends herd-level monitoring for ketosis on an ongoing basis. This will show when cows are slipping into negative energy balance to the extent that ketosis develops.
In herds where more than 25% of cows test positive for ketosis, management and feeding policies during the transition period should be reviewed.
Elanco’s Keto-Test, a cow-side milk testing kit, allows farmers to be more proactive in protecting their herds from ketosis.