Vaccinations

Bovine Viral Diarrhoea (BVD) is a pestivirus of cattle, it is a multifactoral disease of cattle causing many clinical signs. These include abortion, infertility, an immuno-supression that underlies calf respiratory and enteric disease and mucosal disease, a fatal wasting disease of adult cattle.

The disease is maintained by a small population of animals that become persistently infected (PI) with the virus. These PI animals are the major reservoir of BVDV and arise after becoming infected whilst in the uterus during early pregnancy.

Such infections remain throughout the pregnancy and, after birth, for the lifetime of the animal. Interestingly, although infection of the foetus results in a persistent infection, the mother is only transiently infected and becomes immune to the virus within 2-3 weeks. PI calves often die prematurely with respiratory or enteric disease but may also live a relatively normal life for several years; all the time, shedding large amounts of virus and acting as a reservoir of infection for in-contact cattle.

Thus, PIs are the main and most significant source of infection of BVD virus. Removing PIs from the population, removes the source of infection and reduces the disease reproduction rate to the point that the virus cannot survive and the disease is controlled. There are other methods of virus maintenance and transmission, but they are considered of lesser significance in maintaining the disease.

Good diagnostic tests exist to detect both the PI animals and also the antibody status of the herd (i.e. to indicate whether BVD virus is present and circulating within a group of cattle). Good vaccines exist to protect breeding cattle and prevent the creation and birth of PIs. This disease is now eminently controllable.

This endemic viral disease of cattle is common in the UK and causes significant losses. Herds with BVD suffer infertility and reproductive disorders. Their health is poor, with problems such as pneumonia and scour. The disease may be insidious and protracted; you get used to living with the problem in the herd, to the point where you don’t realise how badly it affects you – until it is gone.

Control of BVD 

Identification of the PI Animal 

In order to control BVD effectively you must remove any PI animals. To start the process a bulk milk sample should be tested to look for PI animals in your herd, if positive we can start to blood sample individuals to find the PI animal. Speak to one of our Vets to arrange an individual protocol tailored to your herd.

All calves are now issued tags and tested for BVD under the eradication scheme.

Vaccination

There are two vaccines available, one is a single injection which lasts for 1 year, the other consists of a primary course of 2 injections spaced 4 weeks apart, the second injection needs to be given 4 weeks prior to service to provide protection to the new foetus. This vaccine requires 6 monthly booster injections.

Please speak with one of our vets who will advise you on the most suitable course for your herd.

Clostridial diseases are major pathogens that can be fatal to cattle. Of these bacteria the most common is blackleg, and cattle are most susceptible when they are initially turned out to pasture or when soil has been overturned within the pasture.

Blackleg is a highly fatal disease of cattle caused by the bacterium Clostridium chauvoei. Infection begins when bacterial spores are eaten usually via soil. The bacteria damage the muscle and produce a poison that enters the bloodstream causing a septicaemia and resulting in an animal that rapidly dies.

The disease is most commonly seen in calves between six months and two years of age. Disease is most common in animals that are growing well.

Clinical Signs

• Sudden death in an otherwise apparently normal animal
• The carcass often bloats and has gas under the skin of affected hindlimbs
• Bloody discharge from the nose, mouth and other body openings can also be seen

Diagnosis

• The above clinical signs
• A post mortem is essential to diagnose blackleg.

Prevention

As the bacteria are present in the soil, preventing access to soil by not grazing freshly sown pastures with youngstock can reduce the risk, but vaccination is really the only effective means of controlling blackleg.

We offer a straight blackleg only vaccine and also a combination vaccine which includes protection against 9 other clostridial diseases.

Vaccination

The vaccine protocol is 2 injections spaced 4-6 weeks apart, with the 2nd injection being 10-14 days prior to the risk period.

In high risk areas we would recommend booster vaccination every 6-12 months.

Please contact our vets if you require any more information.

IBR is caused by the bovine herpes virus. This virus causes three different types of disease: respiratory disease (IBR), venereal disease and brain disease in calves. The main disease we see within the practice is the respiratory form.

Clinical Signs

• Nasal discharge
• Conjunctivitis (red eyes)
• High temperature and milk drop
• Loss of appetite
• Pneumonia signs
• Death in extreme cases

Diagnosis

On the clinical signs described above. The signs of IBR are variable. In some outbreaks, little more than a runny nose and red eyes is seen, although drops in milk yield can be large, despite the apparently mild disease.

• Nasal samples for virus testing from the respiratory tract
• Blood testing for antibodies can identify infected cattle, particularly if paired samples are taken (3 weeks apart)
• Post mortem examinations
• Bulk milk tests

Prevention

• Biosecurity – Bought in cattle are the main source of the virus
• Environment – Adequate ventilation is needed to create a healthy environment for your herd
• Vaccination – There are several effective vaccines on the market. The main problem with most vaccines is that they produce antibodies, which cannot be distinguished from those caused by natural infection. Thus, vaccinated cattle cannot be separated from latently infected cattle. A new marker vaccine is now available, which does not produce the same antibodies as natural infection. This is helpful if you are trying to eliminate, rather than control IBR

Remember vaccination in the face of an outbreak has been proven to reduce the severity of spread through your herd.

Please contact the clinic to speak to one of our vets if you require more information.

These spiral bacteria are common causes of disease in cattle. Infection is associated with milk drop syndrome, abortion, weak calves and infertility. Leptospirosis can spread from cattle to man, causing flu-like symptoms and severe headaches (Weils disease).

In the UK the most common bacteria is Leptospira borgpetersenii serovar hardjo. Probably around 60% of herds in the UK have been exposed to leptospirosis.

Clinical Signs

Milk Drop Syndrome 

• Sudden large drop in milk production (in some cows it may stop altogether)
• Affected cows may have a high temperature
• All four quarters are affected. The udder is usually soft and flabby and the milk is colostrum-like, with a high cell count but no bacteria
• Milk drop usually lasts around six days. In some outbreaks 50% of the herd may be affected severely depressing milk production

Abortion

• Most cases of abortion occur in the second half of pregnancy
• Infection close to calving usually leads to small weak calves rather than abortion
• There is an increased incidence of abortions in the spring time as this is the main season of transmission for Lepto
• Unlike milk drop which occurs very soon after infection, abortion occurs  4 to 12 weeks afterwards

Infertility

Leptospirosis has been linked to infertility problems such as reduced pregnancy rates and irregular returns to oestrus.

However, abortion is the most common fertility problem associated with leptospirosis.

Control of Leptospirosis

Diagnosis

• Blood testing of affected animals can be a very useful confirmation
• Bulk milk testing can be helpful in dairy herds
• Examination of the aborted calf will occasionally confirm infection in the calf, but is more useful for identifying causes of abortion other than leptospirosis
• In dairy cattle the risk of spread to humans is increased as there is much greater contact with urine which is the main source of the bacteria. Thus even in herds with no obvious clinical disease prevention is important

Vaccination

It will significantly reduce the level of abortion, and greatly reduce the spread of disease from cattle to man. Several leptospirosis vaccines are available.

Vaccination is administered via two injections spaced at least 4 weeks apart, the course should be completed in the spring before the main season of transmission of L. hardjo. Yearly boosters are required to maintain effectiveness.

This yearly booster is important, as vaccination prevents disease but does not eliminate the organism from the farm, so stopping vaccination often results in the recurrence of the disease.

Please contact the clinic if you require more information or a vaccination protocol tailored specifically for your farm.

Diseases caused by Salmonella bacteria are some of the most important diseases found in cattle. Not because they are very common or because infection causes high disease and death rates, but because all salmonellae found in cattle can potentially spread to humans.

A wide range of salmonellae have been isolated from cattle in the UK, most of them only occasionally. The most common type of Salmonella affecting cattle in the UK is currently Salmonella Dublin.

Clinical Signs

S. Dublin causes a wide range of diseases in cattle, not just diarrhoea.

Disease in Adult Cattle

• Fever, dullness, decreased appetite and milk drop
• Severe bloody (and often watery) diarrhoea with blood, mucus and casts
• Death occurs in around 75% of affected animals if they are not treated.
• Abortion due to S. Dublin is the most commonly diagnosed cause of abortion in UK laboratories.

Disease in Calves

This is much more variable. It is usually seen in calves between two and six weeks of age. However, because the disease can be slow to resolve, older infected calves can be seen.

Clinical signs include 

Pasty diarrhoea, which becomes bloody and watery with an offensive odour

• Calves become dehydrated, collapse and die
• Calves may also die suddenly with no previous diarrhoea
• Pneumonia, stiffness, joint-ill and meningitis are also seen

Control of Salmonella

Diagnosis

Diagnosis in affected adults is relatively easy, as large numbers of bacteria are found in faeces (or in aborted calves). In calves a proper post mortem examination is much more useful.

Control and Prevention

In infected herds, infected animals must be separated and isolated away from the rest of the animals.

Ensure that infected cows do not come into contact with calving cows, as they have the highest risk of infection.

Also, ensure that milk from ill cows is not fed to calves, or do not consume unpasteurised milk from infected or in contact cows.

Hygiene is essential.

Clear out and disinfect all calving boxes thoroughly and if you have infected calves clean and disinfect calf pens.

If possible use temporary facilities to allow bacterial numbers to decline even further.

Vaccines are available, however once S. Dublin has entered a herd, vaccination alone will not control the spread of infection. Good husbandry and hygiene is essential if control is to be achieved.

Vaccination

Primary Course 

Two injections spaced 3 weeks apart, the second injection should be given at least 3-4 weeks prior to the high risk period (Calving). This ensures adequate protection at time of risk and provides good maternal antibodies to the calf via the colostrum.

Healthy calves can be vaccinated from 3 weeks of age, and require 2 injections spaced 2-3 weeks apart.

Re-Vaccination

An annual booster is required consisting of a single injection at least 2 weeks prior to the 'at risk' period. Ideally 3-4 weeks prior to calving.

Please contact one of our vets if you require any more information or you wish to discuss a vaccination protocol tailored to your individual farm requirements.