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How to identify acidosis in dairy animals

What to look for - ranges from serious acute disease to milder chronic form.

Acute acidosis

  • Usually within one day of carbohydrate overload
  • May stop eating
  • May appear depressed
  • May be unstable if standing
  • Rumen is often distended (on left side)
  • Tapping left flank may produce splashing sounds
  • May have profuse diarrhoea with an offensive smell
  • May become dehydrated, lie down, and without prompt treatment, are likely to die

Chronic acidosis

  • Usually a herd problem
  • Vague clinical signs
  • Loss of appetite
  • Intermittent diarrhoea
  • Lower milk production
  • Depression


Excess amounts of carbohydrate-rich foods such as grains or fruit. Rumen function is overloaded leading to increased acid in the rumen. Milder forms have a slower onset, but if not managed can lead to long term changes to the rumen.

Animals likely to be affected

Often seen in cows in early lactation. Typically seen after calving, especially in cows that have been fed on pasture during the dry period and the rumen has not had time to adapt to concentrate feeds.

Other diseases with similar signs

  • Acute: infections, milk fever, mastitis or displaced abomasum, other causes of scours
  • Milder chronic forms: may resemble lead poisoning, listeriosis or polioencephalomalacia

Confirming the diagnosis

  • Recent increase in consumption of grain or fruit
  • Test rumen fluid acidity (pH)


Serious cases of acidosis need rapid treatment. In severe cases, your vet can operate to remove the rumen contents and provide other supportive treatments to help get the rumen operating again and prevent infection.

Less severe cases may respond to treatment with magnesium products given by stomach tube. Afterwards, it is important to feed good quality hay and ensure that animals do not have access to water until the next day.

Animals that have mild acidosis should be fed good quality hay and reduced amounts of concentrates. Watch them closely to ensure that any animals that are not improving can be treated more intensively.

Risk factors

  • High carbohydrate feeds not stored securely
  • Cattle introduced rapidly to diets containing high proportion of concentrates


When introducing cattle to concentrates, monitor them closely and check the consistency of their manure.