The following points highlight the three types of Mastitis in cows. The types are: 1. Acute Mastitis 2. Sub-Acute Mastitis 3. Chronic Mastitis.

Type # 1. Acute Mastitis:

It is commonly known as ‘Start’, ‘Garget’, ‘Struck’, ‘Weed’ etc.—occurs mostly in summer and autumn but occasional cases are noted in other seasons. The incidence varies and is specially prevalent is some years depending perhaps to some extent on climatic condition such as warm moist weather.

Cows in milk and dry cows are chief sufferers. The mode of infection is not known. It may occur through an injury or abrasion. It may be transmitted by fitting flies or it may pass up through the teat duct. A predispos­ing factor may be inefficient drying off. Milk left in the udder supplies an excellent media for bac­terial growth and when green food is sufficient, efficient drying is very difficult.

Sores on a teat— specially around the sphincter—may act as a cen­tre from which infection extends. It assumes ma­jor economic importance only in dairy cattle and in terms of economic loss, it is the most important disease which the Dairy industry has to contend.

Etiology:

The most common causes of acute mastitis are staphylococci and corynebacterium pyogenes. Other infective agents have been impli­cated as causes – Streptococcus agalactiae, Str. Uberis, Str. dysgalactae, Str. faecalis, Str. pneumo­niae, Staphylococcus aureus, Escherichia coli, Corynebacterium bovis, Mycobacterium tubercu­losis, Pasteurella multocida etc.

Symptoms:

The symptoms of acute mastitis develop in a few hours. There is fever, marked systematic disturbance, anorexia and cessation of rumination. One or more quarters of the udder are found to be inflamed, ballooned. The affected gland becomes hot, tense, swollen, and reddened and so tender that the animal resents manipula­tion of the part.

The condition is usually noted soon after parturition but it may occur at any stage of lactation. When due to staphylococci only a small quantity of thin reddish or brownish fluid can be expressed from the teat. Systematic symptoms are marked. Sloughing or gangrene are not unlikely consequences and, if not prop­erly treated, death from toxaemia occur in a large percentage of these cases.

So called summer mastitis—due to Corynebacterium pyogenes, is almost always—though not invariably, noted dur­ing summer and autumn. Here, there is a thick purulent foul smelling, greenish-yellow or blood­stained exudate which is often difficult to with­draw from the teat. Abscesses frequently form and rupture externally. Sloughing is rare but con­stitutional disturbance is pronounced.

This form is noted chiefly in dry cows but it may attack lactating cows or even heifers. It varies in inci­dence from year to year and from district to district. In acute streptococcal mastitis, systematic symptoms, though pronounced, are not as severe as in the two above-mentioned forms.

The secre­tion is yellowish fluid containing a variable amount of clotted material and because of the involvement of the teat, it may be difficult to obtain much secretion in early stages. A quarter affected with acute inflammation is never likely to be normal again and there is chance of atrophy of the part. Sometimes, it becomes a seat of a chronic infection.

Treatment:

Special bacterial types of mastitis require specific treatments. Parenteral treatment is advisable in all cases of mastitis in which there is a marked systematic reaction, to control the development of Septicaemia or bacteremia and to assist in the treatment of the infection of the gland.

The systematic reaction can easily be brought under control by standard doses of anti­biotics or Sulphonamides but complete sterilisaton of the affected quarters is seldom achieved be­cause of the relatively poor diffusion of the anti­biotic from the blood stream into the milk. The rate of diffusion is higher in damaged than in normal quarters.

Because of convenience and effi­ciency, udder infusions are preferred method of treatment. For lactating quarters, a preparation containing ampicillin and sodium cloxacillin is effective. In dry quarters, Benzathine cloxacillin in a long acting base is most effective against Streptococci and Staphylococci.

For Gram-nega­tive bacteria, Furaltodone in procaine penicillin is effective. The drug of choice must be determined after the causative organism has been recognised. There are many broad spectrum antibiotics but indiscriminate use of these drugs may encourage drug-resistant organisms.

Type # 2. Sub-Acute Mastitis:

It may result from infection of Streptococcus agalactiae (group II – Minnet), Streptococcus num­ber is (group III – Minnet).

Streptococcus agalactiae is definitely conta­gious. In subacute mastitis, systemic disturbance is not so pronounced. Inflammation of mammary gland is not so acute and tenderness is not so marked. Onset, however, is rapid, there is bal­looning and tenderness of the quarter and secre­tion is a yellowish fluid containing a good deal of clotted material. Owing to this clotting and in­volvement of the teat, there may be some diffi­culty in stripping the teat in early stages. The condition is generally progressive but sometimes symptoms subsides and recurs.

Type # 3. Chronic Mastitis:

It is sometimes due to Staphylococci, occa­sionally to Mycobacterium tuberculosis but is gen­erally due to Streptococcus agalactiae which is the cause of common chronic contagious mastitis in milch cattle.

The later form is contagious and spreads through a herd. Str. agalactiae infection may at times assume a rather severe form and spread rapidly. But usually severe symptoms are due to a flare up of an existing condition and the flare up may be the result of an injury or follow the installation of a milking machine.

Symptoms:

Generally, the onset is slow and there are no systemic symptoms. The first evi­dence of infection is the appearance of small clots in the fore milk and the secretion may become somewhat watery in appearance. This change may pass unnoticed by the milker or if noticed, may not be considered of any importance. After a time, the milk become more watery and clots are found more regularly and continuously from the affected quarter, which at this time, on palpation may exhibit some indurations.

If milking is regular and thorough, development is slow and clinical symptoms may not be apparent for months. But stripping is incomplete, development is more rapid and affected gland eventually atrophies. Symptoms may appear after calving at any period during lactation or while drying off. There is no constitutional disturbance.

Detection of mastitis as well as physical examination of mammary glands:

Because of the expense of laboratory exami­nation of large number of milk samples, much attention has been given to the development of field tests and certain indirect methods are used in an attempt to identify the disease at early stage

(1) The Strip Cup:

This is an aluminium mug covered with a detachable lid. The lid is composed of a circular black slab with a raised brim. The lower edge of the firm is perforated to allow milk drawn on to the slab to pass down into the mug. Clots or flakes in the fore milk can readily be seen against the black background of the lid.

(2) Chemical indicators:

Solutions of indi­cators may be added to milk. But the usual prac­tice is to strip of paper impregnated with indica­tor. The test depends on the fact that milk from an affected quarter is usually alkaline where nor­mal milk is normally amphoteric. A reaction is not invariably given by abnormal milk but it is said that 92% of cows on several repeated tests is negative and are healthy.

Milk from healthy cows may occasionally but will not give regularly a reaction. A reaction does not indicate the type of mastitis, moreover, the test is not applicable to cows within 10 days of calving nor within 6 weeks of drying off. Because, at these periods, the secretion is alkaline. As cream affects the reaction, foremilk should be tested. Indicators used are —

(a) Bromide cresol purple paper:

This is yellow before use. When wetted with normal milk, it becomes dove-grey in colour. When wet­ted with abnormal milk, it assumes a purple colour.

(b) Bromide Thymol Blue paper:

This be­comes greenish with normal milk, bluish or greenish-blue with mastitis milk. Either indicator is yellow to acid milk.

Many early subclinical cases will escape detections by both clinical examination and the application of these tests and where elimination of the disease is aimed at, resort must have to regular laboratory examination of samples of milk from apparently healthy cows. Because of the contagious nature of this Str. agalactiae infection, it is important that immediate methods of control be adopted.

Modern Treatment of Mastitis:

Treatment for Streptococcal agalactiae mastitis — Administration of Trimethoprim and Sulpha-doxin can now be regarded only as a first aid remedy and it is followed by disappearance of clinical symptoms in the large proportion of cases. Penicillin G at present is the drug of choice, because it is of high efficiency, causes little or no irritation or decrease in milk yield in milking cows and so far shows no likelihood of producing resistant strains.

The method of udder infusion should always be from collapsible single dose tubes because, in most careful hands, there is danger of transmitting other pathogens or fungi if other methods are used. It should be either in ointment or water soluble base and diffusion is same in both cases.

For removal of symptoms in a clinical quarter 1,00,000 units should be used once a day after complete stripping or smaller dose two or more times a day. The rate of diffu­sion is greater in damaged than in normal quar­ter. Response is usually quick but when symp­toms have disappeared, treatment should be con­tinued for further 2 days.

For eradication pur­poses where it is necessary to sterilise as near 100% as possible, treatment should be such that bactericidal concentrations are maintained in the udder for 5 or 6 days.

Intramammary injection after complete stripping specially in the afternoon should be as follows:

(a) 5 doses of 50,000 or 1,00,000 i.u. of peni­cillin G at daily intervals.

(b) 3 doses of 1,00,000 i.u. of Penicillin G at intervals of 48 hours or

(c) 2 doses of 1,00,000 i.u of Procaine peni­cillin at intervals of 72 hours, all sterilise about 90% of infection.

Treatment of other forms of mastitis in milch cows:

Penicillin is of considerable value in the removal of clinical symptoms in other forms of streptococcal mastitis and staphylococcal mastitis, provided the condition is not already too ad­vanced or an acute case due to dysgalactiae. For staphylococcal infection, Streptomycin -1g + Peni­cillin – 1,00,000 i.u. – 3 infusions at 24 hour int­erval are quite effective and cure rate is about 65%.

For other forms of mastitis due to other bacteria, there are several other antibiotics such as Benzathine Cloxacillin, Procaine Penicillin; Dihydrostreptomycin, Spiramycin, Rifapycin, Tet­racycline, Chloramphenicol, Neomycin etc. and the drug of choice should be selected according to causative organism. In clinical cases of chronic mastitis which do not respond to Penicillin, one of the more active Sulfanilamides should be tried.

Necropsy Findings:

It is not of major inter­est in diagnosis of mastitis.

Control:

Infected animals should be placed at one end of the byre and milked last. Doubtful animals are placed in the middle and the healthy animals are placed at the other end of the byre and milked first when milking machine is used. It is advisable to provide separate units for affected animals or have them hand milked by special attendants. Foremilk should be collected in a strip cup. Badly affected animals should be removed.

If periodic (say 3 months), laboratory tests and proper control measures are carried out, the dis­ease can be eradicated by gradual removal of affected and replacement by healthy stock. Newly purchased animals should be isolated until tested and, if possible, only first calvers brought in as they are most likely to be free from disease.

The essential steps that should be taken are:

(1) Treatment of all quarters of all cows in the herd with infusions of 1,00,000 I.U. of penicil­lin after 5 successive evening milkings,

(2) Application of penicillin cream to the hands of milkers and the teats of all cows for 14 days, udder clothes should be clean and changed frequently and disinfected daily.

Physical Examination:

The time to make a clinical examination is when the udder is empty. At no other time can slight abnormalities be de­tected. One should know the symmetry of quar­ters, then palpate the whole surface with the finger tips for evidence of fibrosis in the glands or changes in the integument. Feel the teat duct and note if it is thick. Using both hands, raise corre­sponding quarters and note their relative size and consistency around the lactiferous sinus.

Lobula­tion may be noted by taking each quarter be­tween the two hands and moving it backward and forward under fairly firm compression. Ex­tend examinated upwards, paying particular at­tention to the posterior border of hind quarters. Lastly, palpate—if possible—the Supermmary lymph glands but do not forget that this gland is not necessarily enlarged in Tuberculous mastitis.

Home››Animals››Diseases››