Ketosis
4 min read
Clinical ketosis is a metabolic disease in cows, occurring when they are in severe negative energy balance, particularly during early lactation and may occur as a secondary condition to other health challenges the cow may be experiencing. The disease forms when cows can't effectively convert mobilised body fat to energy, leading to an excess of ketone bodies and often low glucose in blood.
In early lactation, all cows experience negative energy balance; however, the severity of this can vary. During severe negative energy balance, the cow mobilises excessive amounts of body fat but cannot convert this to energy through the usual pathways. Instead, ketone bodies such as β-hydroxybutyrate (BHB) are produced. In small amounts, the cow can use BHB as an alternative energy source. However, when ketone production is high, the cow cannot use all the ketone bodies for energy and BHB concentrations increase in the blood. When this occurs, alongside other clinical signs, the cow may suffer from clinical ketosis.
Diagnosing clinical ketosis includes checking for clinical signs and analysing blood BHB concentration during physical examination. It's essential to manage feed allocation and body condition scores to reduce clinical ketosis risk. If a cow shows clinical signs of Ketosis, you should consult your vet. Increase the energy content of the diet or provide oral drenches for treatment. Treating cows with elevated blood BHB concentration using monopropylene glycol drench, without clinical signs of disease, is not recommended.
Ketosis can be displayed in these ways:
Wasting form:
Nervous form (less common):
Overconditioned cows
Cows that are too fat at calving (BCS >5 mixed aged cows; BCS >5.5 heifers and second-calving cows) have an increased risk of clinical ketosis. For example, cows that calve at BCS 6.0 are twice as likely to suffer from ketosis than cows that calves BCS 5.5.
Cows that have been overfed pre-calving are also at risk of clinical ketosis. Refer to the feeding guidelines for transition cows.
Underfed cows
Cows that experience a sudden drop in energy intake are at risk of clinical ketosis. This can be due to underfeeding due to insufficient feed, poor quality silage, or adverse weather events.
Poor quality silage can impact rumen function and reduce a cows’ appetite. Silage undergoes a secondary fermentation and when ingested will increase the risk of dietary ketosis. See grass silage for more information on silage quality and testing.
Cows that have been underfed pre or post-calving are at risk of clinical ketosis. Refer to the feeding guidelines for transition cows.
Secondary or underlying health issue
A secondary or underlying issue may result in a reduced appetite that prevents cows from eating sufficient amounts of dry matter (i.e. clinical milk fever).
Responding to an inflammatory event can also cost a lot of energy with recent research suggesting that a dairy cow uses more than 1 kg of glucose within 12 hours when her immune system is activated. This can result in insufficient energy intake to meet demands increasing clinical ketosis risk.
Clinical ketosis can be prevented by managing feed allocation to ensure feed supply meets feed demand and BCS (both pre- and post-calving), appropriate transition cow management to reduce hypocalcaemia risk, and by paying attention to cow behaviour and adverse weather conditions.
Management strategies to reduce the risk of clinical ketosis
If a cow shows symptoms of clinical ketosis, seek advice from your vet. Successful treatment of clinical ketosis will involve providing cows with oral drenches that stimulate an increase in blood glucose. Treatments that have been used in severely affected cows include intravenous metabolic solutions (e.g. 4-in-1; Ca, Mg, P, glucose), intravenous dextrose, multivitamin injections, and use of oral monopropylene glycol drenches.
If the affected animal is still able to stand, increase the energy content of the diet supported by oral drenching (twice daily) of glucose precursors such as monopropylene glycol.
If the animal is not able to stand, provide it with shelter, soft bedding, and continued nursing, including regular rolling from side to side to avoid sores.
Use hip-lifters or similar lifting devices to assist the affected cow to her feet for some time. Hip clamps can only be used to help a cow stand, but not to keep her standing or to move a cow. For more information on lifting see down cows.
Monensin contains monensin sodium, which alters the rumen microbial population to increase priopionate relative to butyrate. Monensin lowers blood BHB concentrations and may reduce the risk of clinical ketosis in grazing dairy cows; however, it does not improve subsequent reproductive performance when fed immediately before or after calving. Research on the treatment of hyperketonaemia using monopropylene glycol drench was undertaken by DairyNZ in 2016 but had no economically important benefits when routinely administered to hyperketonaemic cows postcalving, see more about Blood BHB and cow performance.
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