Many diseases can be prevented or controlled through sound management practices and good care of animals. It is now known that, in the case of Mastitis, too, there are successful measures the farmer can take to ensure control.

Mastitis is an inflammation of the udder and is caused mainly by bacterial infection. Most of the infections are caused by bacteria known as Staphylococci and Streptococci.

The main sources of these bacteria are udders already infected as well as sores on teats and udders in which the bacteria may be present. The bacteria spread from these sources to healthy quarters, mainly during milking.

The bacteria penetrate the udder through the teat canal where bacterial infection and inflammation set in. Most of these inflammations are so slight and limited that they are not noticed at all by the milker, or last only for a very short period.


Almost without exception, all herds are infected with contagious Mastitis at some stage. The milker will normally detect only one or two cases each day from every 100 cows. Treatment usually eliminates the symptoms. This does not, however, mean that the quarter has now healed or been freed from the bacteria responsible for the infection. The cow seems normal but the inflammation has often simply assumed a less recognisable form. Even with good treatment, complete healing is achieved in only 50% of cases.

Cows often have inflamed udders without this condition being visible. In actual fact, half of all cows have inflamed udders, and this can be determined only by means of laboratory tests. This means that in a herd of 100 cows, 50 may have mastitis in a sub-clinical form (not noticed by the milker). The milker may spot only about two cows with visible mastitis.

Figure 1: Incidence of visible mastitis

48% of the cows may have sub-clinical mastits, which the milker does not detect.
  • Such undetected cases are dangerous for several reasons:
  • The udder tissue is continually damaged over a long period and destroyed, and during this process, the infected quarter is a continual source of bacteria which may infect the other healthy cows and quarters;
  • In addition, dairy farmers often fail to take special measures to disinfect the teats and  udders of an apparently healthy animal, consequently new case of infection occur  continually in otherwise healthy and even young animals. Such infection takes place during lactation as well as during dry period;
  • The treatment of a cow with obvious mastitis is essential to save the quarter, and sometimes the life of a cow, but it cannot solve the mastitis problem. The reason for this is, that too few of the inflamed udders are included in the treatment and;
  • Treatment of lactating udders is also expensive and relatively ineffective, depending on the nature of the organism and the degree of inflammation. Apparent recovery often occurs while the quarter is still secreting bacteria. Consequently clinical mastitis may reappear from time to time and the milk-secreting tissue may still be attacked.

Figure 2: The incidence and pattern of Mastitis: As the problem really is:


The importance of Mastitis Control and the Cost of this control are two aspects which must be examined.

In most herds half of the cows usually suffer from udder inflammation. On average, cows with inflamed udders produce 10% less milk than cows with healthy udders. The B.F. and S.N.F. of the  milk are reduced by 0.2%. Where clinical mastitis occurs, the drop in milk production, as well as deterioration in the composition, is far greater.

Provided the udders with sub-clinical mastitis can be healed, the udder tissue will recover to such an extent during the dry period that milk production will usually be almost normal during the next lactation.

In a Herd of 100 cows with sub-clinical Mastitis

Average production of 4000kg per lactation for each cow: Loss of 400kg for each of 50 infected cows

= 20 000kg loss of milk. This is a 10% reduction. If this is multiplied by the price of milk per litre, we get a very significant loss.

In a herd of 100 cows with clinical mastitis

We record 100 cases of clinical mastitis every year.

Milk is discarded for 4 – 5 days depending on the response to treatment. An average loss of 20kg from each cow = 100 cows = 2000kg.

To this loss of income we must add the cost of treatment to get the total cost of the mastitis.

Cows may die from Mastitis; if the disease does not kill them, it reduces their productive life. Farmers are aware of culling animals because of mastitis. Just consider the cost of labour and food for unproductive animals.

Antibiotics in milk subsequent to being treated gives rise  to great economic problems in manufacture of dairy products,  such as cheese and yoghurt, and also a health problem to the

consumer. Mastitis milk is full of leucocytes. Some bacteria can poison consumers.


The rudiments of any Mastitis-control system are included as follows:

  • To prevent cows from contracting udder infection;
  • To eliminate udder infection which occurs in spite of a control programme and;
  • To eliminate udder infection already present when the control system started.

Prevention of any new udder-infection may eventually be sufficient to control mastitis, but  at present it will have to be accompanied by the elimination of infection. No preventative programme  is absolutely successful and therefore new cases of udder infection will occur and have to be eliminated.

It is also essential to eliminate infection present when the control programme is started, as 50% of all cows are already infected.


Udder-infection can be prevented by careful management of the dairy herd. The following are important points to be kept in mind at all times:

  • Provide a clean and dry place for cows to sleep;
  • Adhere to a regular milking routine;
  • Avoid practices which damage teats in any way;
  • When milking machines are used, handle the machines according to the manufacturer’s instructions. (Do not try to handle more machines than the milker can cope with.) and;
  • Avoid over-milking.

Even in herds where management in general is perfect, mastitis may be a great problem. Certain principles of hygiene must be applied in milking so that management is complete.


The hygienic aspects of milking deserve careful attention. Mastitis-producing bacteria are transmitted from infected to uninfected quarters mainly by wash cloths, washing water, hands of  the milker and by means of the milking machine.

Figure 3: Spreading the infection of Mastitis

·         Washing Water:

It is preferable to use clean water from a hose for washing udders. If this is not available, use clean water in a bucket with a disinfectant added. Do not wait until the water is dirty before replacing it.

·         Udder Cloths:

Transmission of bacteria is prevented by the use of separate paper towels or cloths boiled beforehand (use one cloth per cow) for udder working.

·         Hands of the Milker

Bare hands cannot be disinfected properly, but the transmission of bacteria can be limited  by wearing rubber gloves rinsed in a disinfectant before and after handling each cow. N.B. Scrub the gloves under running water and dip in teat dip (1:3) between milking the cows.

·         Milking Machine Clusters:

Germs can be killed by washing with a hot disinfectant solution after milking. Do not use hot water to rinse the clusters between cows. This can burn the teats of the second cow.

  • Thoroughly clean teat tip and the opening with methanol, before any antibiotic is inserted.
  • Administer an antibiotic immediately after the last milking of a lactation.


  • Milker must wear gloves;
    • Rinse gloves in disinfectant before and after each milking;
    • Test for clinical mastitis before the udder is washed;
    • Wash udders thoroughly;
    • Cow can now be milked and;
    • Disinfect each teat after milking.

At first glance it seems to be a complicated procedure, but when routine is established, the programme is easy to carry out.

The successful treatment of mastitis with a view to eliminating it requires veterinary advice. Clinical Mastitis may be the result of an udder injury, but it usually results from bacterial or other infection. As a rule, antibiotics are used to treat bacterial mastitis. These should be used with great care since:

  • Antibiotics in milk may be injurious to the health of the consumer;
    • Antibiotics in milk give rise to problems in the manufacture of dairy products and;
    • When antibiotics are administered irresponsibly, without very thorough disinfection of the teat tip and the teat opening, other germs not susceptible to antibiotics may be pushed into the teat by the syringe.

This may cause mastitis and, in fact, this type of inflammation is often far more serious because healing is so much more difficult to achieve.

Consult your Veterinarian at all times. His recommendations will include the following:

  • Choice of antibiotic;
    • Disinfection of teat opening before treatment;.
    • Treatment of clinical mastitis during lactation
    • Treatment of sub-clinical cases which can be determined by laboratory testing;
    • Treatment of cows when they go dry and;
    • Culling of cows that remain infected after repeated treatment.

When treating animals:

Follow your Veterinarian’s instructions; Apply the whole course;

Keep complete records – for future reference.

When the cow goes dry:

All clinical forms of Mastitis occurring during lactation must be treated, but the treatment of dry cows is strongly recommended. There are several advantages to be gained from treating all cows with a suitable antibiotic preparation when they go dry.

  • All persistent, invisible forms of bacterial infection are treated and eradicated;
    • The treatment is not accompanied by a loss of usable milk;
    • Most of the infections which would otherwise occur during the dry period are prevented;
  • If the infections can be treated when the cows go dry, the milk-producing capacity of the udder tissue will, in most cows, recover completely before the next lactation;
    • The use of antibiotics when the cows go dry is apparently more effective in eliminating infection, than treatment, during lactation and;
    • The chances of contaminating the milk are, of course, greatly reduced.