Bovine Viral Diarrhoea Virus
Information regarding Bovine Johne's Disease (BJD), symptoms of the disease, affected animals, how it can be managed and resources available to help dairy farmers..
This page includes information about conditions of the reproductive system, including strategies to manage or avoid abortion and infertility. Conditions covered here include:
Cows that are not observed to be cycling either prior to or during the mating period.
Cows may not be observed to cycle for several reasons. These include:
Cows in low body condition score and first-calved heifers are most likely to be affected by true anoestrus.
In seasonal/split calving herds, late calving cows are also commonly affected by natural post-calving anoestrus.
Silent heats tend to be more common in larger herds and in higher producing cows.
True anoestrus can be differentiated from other causes of non-cycling by a veterinarian using either palpation or ultrasound. Cows with anovulatory anoestrus have very small ovaries that lack normal structures (follicles and corpus lutea).
There are various hormonal therapies that can be used to re-start the ovaries of cows with true anoestrus. These therapies can also be used effectively in non-cycling cows where the cause is silent heats or cystic ovaries.
For more information see “Non-cycling cows” in Fertility.
Prevention of true anoestrus can be improved in two ways:
For more information on transition cow management and feeding cows well:
Feeding in early lactation page (Feeding & Nutrition Section)
Transition cow management page (Fertility Section)
For more information on managing calving pattern
Calving pattern page (Fertility Section)
Cows with cystic ovaries may be either non-cycling (most common) or have abnormally frequent cycling behaviour.
There are many interacting factors which lead to the development of cystic ovaries. These include nutritional stress, high production, age, genetics and underlying diseases.
Cystic ovaries are most likely to affect older, higher producing cows that have recently calved (1-2 months post-calving).
Cystic ovaries can be diagnosed by a veterinarian using either palpation, ultrasound or laboratory tests. There are four different categories of cystic ovaries that require different treatments.
There are various hormonal therapies that can be used depending on the type of cystic ovaries. Many of the treatments for cows with true anoestrus in non-cycling cows are also useful for treatment of cystic ovaries.
As there are many contributing factors to cystic ovaries, there are no specific prevention strategies. However, improving nutrition in the transition period and between calving and mating, as per non-cycling cow prevention, can be helpful.
Metritis is caused by infection of the uterus and uterine wall with several different types of bacteria.
Cows of any age can be affected by metritis. Metritis usually occurs in the two weeks post-calving.
Diagnosis can be made by considering the history of the cow, for example, recent calving, and observing the symptoms or by conducting a vaginal examination.
Treatment of metritis usually requires injectable antibiotics and anti-inflammatories. Severely sick cows may also require IV fluid therapy.
Intra-uterine treatments such as pessaries or ‘wash outs’ are not recommended as they can cause further irritation to uterine tissues.
Prevention of metritis is best achieved by addressing the risk factors above.
Good transition cow management will reduce the risk of metabolic diseases and calving difficulties. More information on transition cow management can be found here.
It is also important to calve cows on clean, dry pasture or on a clean, dry calving pad. Pasture or pads for calving must have minimal manure contamination. If more than two pats of manure are present per square metre, it is not clean enough for calving cows.
The calving area should be sheltered and well drained. Avoid pugging and mud. If water is visible on the surface or in gumboot prints, it is not dry enough for calving cows. If possible, heifers should be calved separately from the main herd. Heifers are more likely to be bullied and forced to calve in less suitable areas.
It is also important to practice good hygiene when assisting calving cows.
Retained placenta may also be known as ‘retained foetal membranes (RFMs)’.
Placenta that has not been delivered or come away 12 hours or more after calving.
Retained placenta is caused by a complex relationship between immune function, hormone production and uterine muscle contraction.
Cows of any age can be affected by retained placenta after calving.
Diagnosis is usually made by observation of retained placenta. Many cows will also display signs of metritis.
Removal of retained placenta should not be attempted until at least 3–4 days after calving.
If the placenta cannot be removed by very gentle pressure, it should be cut off at the level of the vulva to prevent 'wicking’ of bacteria into the uterus. Never pull on membranes to remove as this is likely to cause tearing and damage to the uterus.
Cows usually do not require any other treatment unless they are showing signs of illness, as antibiotics may interfere with the natural break-down process. Cows showing signs of illness should be treated as for metritis.
As for metritis.
Endometritis is caused by an infection of the inside of the uterus that does not penetrate the uterine wall, usually by bacteria called Arcanobacterium pyogenes.
Cows of any age can be affected by endometritis after calving.
Diagnosis may be made in some cows when pus-like discharge from the uterus is observed.
Many cows will show no visible signs of endometritis, so routine-premating checks of the whole herd or at least at-risk cows is recommended. This can be done by examination with a vaginal speculum or Metricheck® device, which collects a small sample of vaginal discharge for examination.
Treatment of endometritis may involve the use of intra-uterine antibiotics (Metricure®) and/or the use of hormonal therapies. Mild cases of endometritis will self-cure.
As for metritis.
As for metritis.
Occasional abortions occur in normal herds. However, when abortions and stillbirths are affecting more than 1% of late-pregnant cattle, they should be investigated by your veterinarian.
There are several possible causes of abortion in dairy herds including:
The likelihood of abortions will depend on various animal factors such as age and immune status, as well as environmental factors such as exposure to Macrocarpa trees.
Diagnosis of the cause of abortion usually requires laboratory examination of:
Therefore, if abortions are observed, it is important to collect these materials and refrigerate as soon as possible to give the best chance of diagnosis. Most state agriculture departments have subsidies available for abortion investigations.
It is important to note that it can be difficult to pinpoint the exact cause of abortion in many cases, particularly if the appropriate samples are not available.
Treatment requirements will depend on the cause of abortion. Cows that have aborted will be at higher risk of retained placenta.
Appropriate preventative strategies will depend on the cause. Some general prevention strategies may include:
More information on the prevention of BVDV can be found here.
More information about dairy herd biosecurity can be found here.
Between 90% and 95% of heifers that are born a co-twin to a bull calf are freemartins. Freemartins are heifers with congenital abnormalities of their reproductive system and are infertile.
Heifer calves born to twin pregnancies where one calf is male and one is female.
Vulva may appear abnormal with masculine characteristics such as coarse prepuce-like hair.
In some freemartins, external genitalia appear normal.
Freemartins occur when a heifer and bull twin share the uterus and blood supply. Male cells and hormones from the male twin cause abnormal development of the female twin’s reproductive organs. Male twins are unaffected.
Animals likely to be affected
Heifers that are born as a co-twin to a bull calf.
In most cases, diagnosis can be made by a veterinarian by the presence of an abnormally short or absent vagina.
Freemartins do not possess normal reproductive organs and do not cycle so may not be detected until mating or pregnancy testing.
A blood test is also available that may be used to confirm the diagnosis in high genetic merit calves that have normal appearing external genitalia.
There is no treatment for freemartins.
Early diagnosis is important to avoid too much investment in their rearing costs.
There are no problems associated with rearing freemartins for beef production.
Heifers that are born a co-twin to a bull calf.
There is no specific prevention for freemartins. However, the likelihood of a cow conceiving twins is influenced by genetics, so selection for single pregnancies may be considered in herds with high numbers of twin births.