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Information to help you with the causes, risks, and treatment of conditions that cause cows to lie down on their chest or side and remain unable to rise.

Down cows

Conditions that cause cows to lie down on their chest or side and remain unable to rise. When is this happening?

Around calving time

At other times

  • Copy Link Botulism


    What to look for

    • Animals are found dead or paralysed
    • Paralysis usually affects the muscles of the legs, tongue, jaw and throat
    • Affected animals stumble, lie down and are unable to eat, but usually remain upright
    • Characteristic weakness and paralysis of the legs and head
    • Mildly affected cattle may recover over several weeks


    A toxin produced by bacteria (Clostridium botulinum). This bacteria grows only in environments low in oxygen such as inside rotting carcases. Clostridium botulinum produces spores that can last many years in the soil. Cattle are very sensitive to fatal poisoning by the botulism toxin. Exposure most often occurs via rotting carcases of cattle in water courses, carcases of rodents, snakes or possums trapped during hay or silage production, or in rotted food by-products such as brewer's grains, citrus pulp and cannery waste. Outbreaks have occurred in cattle with access to poultry manure that contained poultry carcases.

    Animals likely to be affected

    Animals of any age.

    Other diseases with similar signs

    Other causes of sudden death. May be confused with calving paralysis.

    Confirming the diagnosis

    Identify the toxin in the gut contents of affected animals and/or in material that is suspected of causing the disease.

    Spread of the disease

    Does not spread from animal to animal but multiple cases may occur if a group of animals access toxic material.

    Risks to people

    People do not contract botulism from cattle and the toxin does not pass into their milk.


    Nursing of mild cases can be effective.

    Risk factors

    • Cattle have access to toxic material e.g. dead animals in watercourses
    • Feeding poorly made hay or silage that may contain animal carcases
    • Failure to vaccinate in high risk regions


    In regions where botulism occurs, vaccinate animals that may be exposed to toxic material.

  • Copy Link Acute acidosis


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

    Acute acidosis

    • Usually within 1 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 are 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.

  • Copy Link Grass Tetany

    Grass tetany

    What to look for:

    Can range from mild signs to a rapidly fatal illness:

    • Sudden death
    • Strange behaviour or aggression
    • Convulsions and muscle spasms
    • Over reaction to sounds or movement
    • Collapse
    • Milder cases show poor appetite, slight agitation and reduced milk production

    Cause - low magnesium intake

    Cattle cannot store magnesium so require a daily intake to maintain adequate blood levels. Symptoms occur when the cow's magnesium levels drop below a threshold level. Animals are most at risk when grazing lush pasture especially if it has been fertilized with nitrogen or potash. Outbreaks of grass tetany may be set off by a sudden change of pasture or by bad weather that reduces grazing time.

    Animals likely to be affected

    Dairy cattle within the first 6 weeks after calving. Susceptibility increases with age. Grass tetany is generally a herd problem.

    Other diseases with similar signs

    Other causes of sudden death:

    Diseases causing nervous signs:

    Confirming the diagnosis

    Blood magnesium levels are not a reliable diagnostic test in dead animals, so your vet may take a fluid sample from the back chamber of the eye.


    The aim is to increase blood levels of magnesium as quickly as possible without damaging the heart. Intravenous administration of a magnesium solution is difficult in an animal with convulsions and is best done by your vet. Additional treatment involves injecting magnesium solution under the skin and allowing the animal to recover in a quiet environment.

    Risk factors

    • Grazing on lush pasture, especially if it has been fertilized with nitrogen or potash
    • Cows in early lactation
    • Bad weather or sudden change in pasture


    Magnesium compounds are effective but require daily administration e.g. daily drenching, adding the treatment to feed in the bail, spraying it on to hay, adding it to water or using magnesium blocks. 

  • Copy Link Milk fever

    Milk fever

    What to look for

    • Downer cow shortly before or after calving
    • Most often found lying down, resting upright on the sternum with the head erect
    • Progresses to lying on their side
    • If not treated, will become unconscious and die within a few hours
    • In the early stages cows may be excitable and appear unstable when standing and walking


    Low blood calcium level. Around calving time, cows need to mobilise large amounts of calcium from body stores such as bone. If this occurs too slowly the amount of calcium in the blood may fall below optimal levels resulting in milk fever.

    Animals likely to be affected

    Older, high producing cows in good body condition, shortly before or after calving. Occasionally occurs a few weeks after calving when cows are in oestrus.

    Other diseases with similar signs

    • Causes of downer cows such as calving paralysis, lameness, injury, acute cases of mastitis

    Confirming the diagnosis

    Milk fever is usually diagnosed by the cow's history and her response to treatment. If the cow is found dead, laboratory testing can help rule out other possible causes of sudden death.


    Cows with milk fever need an injection of calcium (usually calcium borogluconate solution) preferably early in the course of the disease. There is little evidence that milk fever treatments containing additional minerals are any more effective than straight calcium products. If the cow is found early, oral calcium supplements or a calcium injection under the skin can be very effective. Injections under the skin can cause problems such as swelling and infection. Your vet may need to give a treatment into the vein but this requires careful monitoring to prevent heart failure.

    Cows need to be watched after treatment because they can appear to recover and then have a relapse some time later. If a cow responds to treatment but is reluctant to get to its feet, it should be encouraged to rise as lying down for long periods can lead to further complications.

    Risk factors

    • Cows calving in good or fat condition
    • Jersey breed
    • Cows with history of milk fever
    • High green feed diet during the transition period
    • Feeds that have had recent application of potash


    Changing the cow's diet during the transition period (from 4 weeks before calving until 4 weeks after calving) can reduce the occurrence of milk fever and other metabolic diseases, and optimise production and fertility. The simplest approach is to restrict the amount of green feed in the last 2 weeks of pregnancy and provide hay from sources that not recently been treated with potash fertilisers. At the other end of the scale cows may be fed a total mixed ration that includes a balance of dietary cations and anions.

    More information

    Transition feeding with limited effective fibre (PDF, 281KB)

    Learn how a pre-calving diet sets up cows for lactation.

    1. Meet her nutritional requirements, not just for maintenance, but also for final development of her foetal calf, and development of her udder.
    2. Give her rumen microbes time to gradually adapt to the milker diet they will need to handle once she calves.
    3. Reduce the chances of her suffering metabolic disorders and other health problems around calving, such as milk fever, grass tetany, ketosis, twisted stomach (displaced abomasum or DA) and retained foetal membranes (RFMs).
    4. Enable her to eat more in the first few critical weeks of her lactation, and thereby lose less body condition and produce more milk.

  • Copy Link Pregnancy Toxaemia

    Pregnancy toxaemia

    What to look for

    Cows in late pregnancy become depressed, stop eating and lose weight. After several days, affected cows will go down and, if not successfully treated, will eventually die.

    Cause - Nutritional stress

    Pregnancy toxaemia occurs when cows in good condition with the high nutritional demands of late pregnancy cannot get enough feed to meet their energy requirements. Under these conditions cow respond by using their fat reserves to provide energy, but in some cases this causes serious metabolic changes and liver damage.

    Animals likely to be affected

    Cows in the last months of pregnancy that are fat (or in good condition)
    Pregnancy toxaemia is usually triggered by a sudden reduction in feed availability or quality.

    Other diseases with similar signs

    Pregnancy toxaemia is one of a number of metabolic diseases that result from nutritional stress and disruption of the cow''s energy metabolism. Fat cow syndrome and ketosis have similarities to pregnancy toxaemia.

    Confirming the diagnosis

    Cows with pregnancy toxaemia have a strong smell of ketones (like acetone-based nail polish remover) on their breath. Laboratory tests can provide information on such things as liver function and the level of ketosis.


    Pregnancy toxaemia is a veterinary emergency which requires loading the animal with energy sources that can be quickly utilised e.g. injecting large volumes of glucose solutions into the vein. In cases it is necessary to induce calving. Animals in an advanced stage of the disease have a poor chance of recovery.

    Risk factors

    • Inclement weather
    • Late pregnant cows that are in very good/fat condition
    • Cows carrying twins
    • Sudden change to a low quality feed or restricted energy intake 


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