Ketosis – intervention and prevention in seasonal calving herds

Ketosis is a common metabolic disease in dairy cattle and occurs when the animal’s energy intake fails to meet its needs, and the cow begins to draw from her body reserves in a continuous state of negative energy balance (NEB). Some degree of NEB is relatively normal in recently calved cows, but the extent to which it occurs and how long it lasts are key factors in how the cow transitions into productive lactation.
“Essentially, ketosis occurs when the metabolic processes in the liver are being overwhelmed, and ketones are produced,” says Maura. “Unfortunately, elevated levels of ketones in the blood, urine or milk result in a suppression of the cow’s appetite, creating a vicious circle that results in weight loss and a drop in milk yield,” she explains.
As well as elevated ketone levels, cows with ketosis can display clinical signs of the condition. Clinical signs include: dullness, reduced feed intake, reduced milk production, and may include behavioural changes such as excessive licking or aggression as well as staggering.
“Clinical ketosis is often the tip of the iceberg, and in many herds, we find that a greater number of cows are suffering from the subclinical form of the disease. Studies have shown that reduced milk yield, lower milk protein production, increased prevalence of LDAs (left displacement of the abomasum) and, ultimately, reduced fertility are all associated with subclinical ketosis, so farmers should really be aware of the impact it can have on the productivity of their herd,” adds Maura.

Body condition score (BCS) at calving is a key determinant of ketosis risk. Fat cows with a BCS of ≥3.5 have reduced late dry period/early lactation feed intake predisposing them to ketosis. Farmers are encouraged to BCS regularly with a BCS of 3.0-3.25 at calving being the target.
While the risk of ketosis is greatest in fat cows, thin cows are also susceptible. Any cow with additional energy needs, such as high yielders, those carrying twins or with any disease or inflammation will also be at risk of ketosis.
“Where possible, farmers should identify ‘at risk’ cows in the weeks prior to calving and remain vigilant in the first couple of weeks of lactation as even correctly conditioned, low-risk cows may be susceptible if stressed; for example, following a caesarean, a difficult calving or a case of milk fever," says Maura.

Treatment

Treatment of ketosis is aimed at re-establishing normal glucose levels and reducing serum ketone concentrations. By breaking the cycle of ketone production, appetite recovers and the animal’s voluntary intake begins to meet energy requirements.
Treatment can include veterinary intervention through the administration of intravenous dextrose and possibly steroids to stimulate glucose production in the liver. For the most part, treatment of ketosis centres on the provision of glucose precursors in the form of glycerol, propylene glycol or propionates.
“Norbrook has introduced a bolus called Ketonor+ that contains propionate as a source of glucose for at risk cows and also contains vitamins A and E, selenium, niacin, cobalt and yeast to support the liver, rumen and immune system. Two Ketonor+ boluses given to ‘at risk’ cows will provide a readily available energy source right when it is needed. This helps to break the cycle of ketone production and helps her to want to start eating again. Ketonor+ is cost-effective, does not contain antimicrobials, has no withdrawal period and is easy to administer in busy seasonal calving herds,” she explains.
Although ketosis is usually seen during very early lactation, it can occur any time that the cow experiences NEB. Many vets are now recommending the use of Ketonor+ boluses alongside pain relief (non-steroidal anti-inflammatory drugs) as well as antibiotics in the treatment of metritis, mastitis, LDAs and even lameness. The theory being that a reduction of pain and sustained energy levels improves welfare and promotes recovery in sick or convalescent cows.
“As an industry we’re increasingly adopting technology like collars, tags and boluses that allow us to monitor subtle physiological changes in individual cows. This technology can indicate very early changes to rumination, activity and body temperature and is able to alert the farmer before the cow displays any visible signs of disease.
Although it can’t offer a definitive diagnosis, feed intake and energy requirements are so finely balanced in those first weeks that these cows may also be at risk of ketosis. In cases like these, early intervention with a bolus is appropriate,” says Maura