'This year has been one of the worst in recent memory for fly infestation'


Risk: Cattle are in danger of contracting summer mastitis and pink-eye from flies
Risk: Cattle are in danger of contracting summer mastitis and pink-eye from flies

Eamon O'Connell

The recent spell of warm and humid weather has suited almost everyone - an abundance of hay and silage has been saved with a resulting re-growth of high quality grass.

However, these benefits come with a literal sting in the tail: flies. This year seems to be the worst in a long time for fly infestation. They are irritating to us, but they pose a much greater risk to cattle and sheep as they act as very effective vectors of disease.

Summer mastitis

This condition results in extremely sick cows and is spread by flies. An affected cow will have a very high temperature, a poor appetite and will appear stiff or slow to walk.

The affected quarter will appear quite swollen and painful and often, more than one quarter will be affected. Early diagnosis is vital as immediate treatment with antibiotics and anti-inflammatory medication is required.

Often, the affected quarter is lost and sometimes, despite everyone's best efforts, the condition can be fatal.

Pregnancy loss can also occur. It is most common in dry cows that are close to calving but it can also occur in heifers, even those less than one year old.

Prevention is most definitely better than cure. A three-step approach is very effective.

1. A pour-on fly repellent repeated at intervals as specified by the manufacturer.

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2. Stockholm tar applied to the teats and udders of at-risk animals every 10 days. Applying tar is a messy job that is not without risk. A second pair of hands is necessary to hold the animal's tail so as to prevent the applicator getting kicked. Use arm length gloves so as to avoid an "eau de tar" perfume/aftershave effect.

3. Infected animals should be isolated from the group. If the offending quarter is milked out, the 'milk' should be carefully discarded. Animals with sore teats are at higher risk as are animals grazing well sheltered fields that have not been topped.


This is a contagious bacterial infection that is transmitted by flies. If the condition is not treated early, the affected animal may become permanently blind, and in very advanced cases, the eye may have to be surgically removed.

The first sign to look out for is a clear discharge from the corner of the eye, wetting the skin and hair beneath. The condition will progress to inflammation and redness of the conjunctiva, which will culminate in an infected and damaged cornea.

There are tubes available specifically for treating pink-eye but the most effective treatment is by sub-conjunctival antibiotic injection. Your vet will be able to do this. Again, it requires an extra pair of hands as the animal needs to be restrained and held quite still.

Prevention involves using pour-on fly repellent products. Some people find fly tags useful also.

Unless infected animals are removed from the group, prevention of spread will be unsuccessful. Even with the most effective fly repellent products, the condition can still be spread by direct contact at meal/water troughs.


A condition that affects sheep whereby flies lay eggs on dirty wool or on an open wound. After hatching, the maggots bury themselves in the wool and eventually in the skin, feeding off the sheep's flesh.

As you can imagine, this is a very painful condition that, if left untreated, can be fatal.

Sheep will, in the early stages, show signs of agitation such as foot stamping or nibbling at the affected area. The affected area of the fleece will appear green or wet looking.

The most common areas affected are around the tail and haunches. In male sheep, the penile area is common affected also.

There is often a strong characteristic smell from affected sheep, and in advanced cases, the wool at affected areas can begin to shed. Care should be taken to check the entire fleece of an affected animal including the feet.

Veterinary advice and attention should be sought for affected sheep.

Dagging aids greatly in the prevention of flystrike. This refers to the cutting away of dirty wet wool from around the tail and anus of sheep.

There are pour-on products available to prevent flystrike but it is important to note that some products that prevent strike don't actually treat the condition if it already exists.

Your vet is best-placed to advise you on the different products that are available.

Eamon O'Connell is a vet with the Summerhill Veterinary Clinic, Nenagh, Co Tipperary


It's time to finalise the autumn and winter vaccination programme


For spring calving herds, vaccination against salmonella usually takes place in late autumn. The exact timing should be discussed with your vet and will be determined by factors such as calving spread and herd history.

Cows receive a yearly booster but heifers need two injections, three weeks apart. Bovivac S is the only licensed product available in Ireland. Due to shortages at peak times in recent years, I would advise everyone to plan ahead. Popping into town on the morning you need the vaccine could lead to disappointment.

In herds where Salmonella has caused problems in calves, they can be vaccinated at three weeks of age, with a booster required 14-21 days later.


There are two products licensed in Ireland: Spirovac and Lepatvoid H. There has been a severe shortage of both vaccines this year.

If it has been greater than one year since cows have been vaccinated, then they should be treated like heifers and receive two shots separated by 4-6 weeks.

As both vaccines become available over the coming weeks, a decision will have to be made regarding the timing of vaccination.

In parts of the country where intensive spring-calving dairy farming is common, it may be the case this year that winter vaccination against leptospirosis could be the most effective method of control.

Cows will be under less stress at the back end of the year and farmers may be less busy also.

However, every farm is different; as with all vaccination protocols, your vet is best placed to advise you on the correct course of action to take that is specific to your farm.

Respiratory disease

When it comes to vaccinating for IBR, it is important to stick rigidly to booster dates.

The live IBR vaccine needs to be boostered every six months. Letting it slide by a few weeks is ill-advised as it can leave animals unprotected and exposed to an outbreak

Weanlings (pictured below) should have their vaccination courses complete prior to a period of stress. The most significant stress period that is coming up soon is weaning.

There are a number of vaccines available against the varying causes of respiratory disease in weanlings. You should sit down with your vet and discuss what vaccines suit your particular system best, taking into account disease history on farm, housing facilities and handling facilities.

Storing vaccines

All vaccines should be stored in a functioning fridge at the correct temperature. Transport vaccines from your local vet clinic in a 'cool bag' and transfer them immediately to the fridge until right before they will be used.

Increased temperatures can render vaccines ineffective so leaving them in the car for a prolonged period is ill-advised.

They are not cheap but they ultimately save the purchaser much more than they cost. It is important to handle, store and use them correctly.

Indo Farming

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