This is a metabolic disorder that occurs in cattle when energy demands (e.g. high milk production) exceed energy intake and result in a negative energy balance. Usually occurs within a few days to a few weeks after calving.
Ketosis cows often have low blood glucose (blood sugar) concentrations. When blood glucose level is too low, the cow mobilizes body reserves, especially fat. This is caused by increased demands of nutrients in milk production and secretion. Part of the mobilized fat will be converted to ketones (e.g. acetone) in the liver due to incomplete oxidation of the fatty acids, which would result in high ketone levels in the blood and if the cow is not eating enough high energy feed, a negative energy balance occurs. When large amounts of body fat are utilized as an energy source to support production, fat is sometimes mobilized faster than the liver can properly metabolize it. If this situation occurs, ketone production exceeds ketone utilization by the cow, and ketosis results.
- In the beef cow, this is most likely to occur in late pregnancy when the cow’s appetite is at its lowest and the energy requirement of the growing calf near its peak.
- In the dairy cow, the mismatch between input and output usually occurs in the first few weeks of lactation, because the cow is not able to eat enough to match the energy lost in the milk.
TYPES OF KETOSIS
- Occurs when high producing cows cannot eat enough carbohydrates.
- When the feed available is somewhat deficient in carbohydrate.
- Occurs when a primary problem or disease causes an upset in the digestion or metabolism of carbohydrate.
The primary diseases that act as predisposing factors include:
- Displaced abomasum
- Milk fever
- Retained placenta
In short this is what happens:
- Low dry matter (energy) intake
- Fat mobilization
- Fatty liver/ketosis
- Impaired liver function
- Off feed- sudden drop in appetite
- Dull coat
- Weight loss
- Decreased milk production
- Mucous covered faeces
- Acetone (pear drop) smell of breath, milk and urine
- A starring expression
- A humped back suggesting mild abdominal pain
- Some animals may develop nervous signs such as salivation, chewing, incoordination, blindness and aggression
- Biting of feeding and drinking utensils
- Licking on various things
- Head tilting
- Having an excited appearance (like a rabid dog)
- Bellowing and charging to people
- Will exhibit selective appetite
- First refusing silage
- then refusing grain
- then hay
- Manure becomes scanty, firm and covered with mucus
- Milk will decrease over 2 to 4 days
- Cow becomes gaunt and sleepy
Effective treatment can be achieved if it is administered in time. Ketosis can be treated by a veterinarian with:
- Intravenously injecting 500ml of 40% glucose (dextrose solutions) to increase blood glucose so as to decrease ketone concentrations.
- Plus twice daily oral dosing/ drenching of 150ml of propylene glycol (a glucose precursor) or Sodium propionate for 4 days.
- Hormonal treatment: glucocorticoids (cortisone) cause the cow’s body to produce glucose from Protein tissues.
It is important to prevent ketosis from occurring, rather than treating cases as they appear.
Prevention depends on adequate feeding and management practices.
- It is very important to keep cows in a good condition but not fat during the dry period therefore, in times of feed deficiency because of drought or other reasons, the provision of supplementary feed with adequate amounts of carbohydrate is essential. The best feeds tend to be good quality hay, silage, or cereal grain.
- The body condition of the dairy cow is important at calving. Cows should be on a rising plane of nutrition up to calving with the aim to calve in good condition.
- Avoid over fattening during lactation and dry period (maintain 3.5 to 3.75 body score) not too fat.
- After calving, the cow has the potential to reach maximum efficiency in milk production, but feed requirements for high production are often greater than the voluntary intake of pasture can provide.
- Therefore an energy supplement is required and there is evidence that this will improve production and reproductive performance, and decrease the risk of ketosis.
- Supplements should be fed at least until the peak of lactation is reached or longer depending on the quality and quantity of available pasture.
- Feed diets with adequate protein not high in protein.
- Feed total mixed rations if possible.
- Provide opportunities for cows to exercise.
- Occasionally, very high-producing cows will be susceptible to ketosis every year. In these cases a preventive drenching program of propylene glycol immediately after calving may avert ketosis in individual problem cows.