MastitisIn Sheep & Goat

Dr.Ali Al-Ahmood2008

MastitisMastitis is a general term which refers to inflammation of the mammary gland, regardless of cause. It is characterized by physical, chemical, and usually bacteriological changes in the milk and by pathological changes in the udder. Early recognition and prompt treatment are important for limiting tissue damage and production losses. However, since treatment is often unrewarding, emphasis should be on mastitis control and prevention.

Specific udder examination:

1. Visually and by palpation.2. compare the two halves.3. heat.4. swelling.5. lumps.6. extent of fibrosis.7. injuries to teats of body of udder.8. superficial inguinal lymph nodes.

Causes Of Mastitis:

An udder quarter becomes infected when:

1. the teats are exposed to pathogens.2. the pathogens penetrate the teat duct.3. the infection is established within the udder.

Infectious Causes Of Mastitis

1. Retroviral mastitis (Hard udder).2. Mycoplasma Mastitis.

3. Bacterial Mastitis.

Types Of Mastitis

Coliform Mastitis:

Coliform mastitis seems to be less common among small ruminant when compared with cattle. E.coli and Klebsiella species are the most common coliform bacteria implicated in mastitis. Coliform mastitis is more common in the post-parturient period and is associated with severe systemic disease. It can be either a persistent or transient infection.

Clinical signs:

- Affected animals perhaps have fever.- Anorexia.

- Apparent depression.

- Lethargy.

- High heart rate.

- Milk changes to a small volume of a watery serosanguineous secretion.

- Palpation of the gland reveals heat, swelling, edema and pain.

- Endotoxin and inflammation may cause vascular thrombosis and gangrene.

Prevention:

- Coliform bacteria are environmental pathogens. Therefore control measures should be aimed at proper hygiene.

- Milking clean.

- Dry teat.

- Providing teat dips.

- Bedding should be kept clean and dry.

- Vaccination against gram-negative "core proteins" may be beneficial.

Treatment:

- Antiinflammatory drugs ; flunixin meglumine 1 to 2 mg/kg IV.

- Systemic antibiotics ; oxytetracycline 10 mg/kg IV.

- IV fluid therapy as needed.

- Aminoglycoside antibiotics should be avoided in food producing animals.

- IV administration of 5% hypertonic saline solution.

Subclinical Mastitis:

Subclinical mastitis is one of the most common causes of culling animals from the flock. As the name implies, it is a form of mastitis or inflammation of the mammary gland that insidiously drains the animal's productive ability. Subclinical mastitis in sheep and goats is caused by a variety of bacteria, including Bacillus species, Staphylococcus epidermidis, E. coli, P. pseudotuberculosis, Omyces and other environmental pathogens.

Clinical Signs:

- Subclinical mastitis may be recognized by poor lamb or kid growth, neonatal malnutrition, and neonatal death caused by starvation in meat breeds.

- In dairy breeds, low daily milk production is the most common finding.

- Udder abscesses are recognized by swelling, edema, or rupture and subsequent purulent exudates.

Prevention:

Preventive measures include keeping all housing and dry lots clean and avoiding muddy areas.

When "drying off" or at weaning, the owner or clinician may choose to infuse halves with a "dry cow" infusion.

If halves were treated during lactation, a different class of antibiotic should be used for "dry off" infusion.

Treatment:

- Penicillin therapy.- In cases of toxic or gangrenous mastitis, treatment

consists of hydration maintenance with either IV or oral fluids or hypertonic saline 4 ml/kg IV.

- Administering NSAIDs ; flunixin meglumine 1 to 2 mg/kg.

- Milking out every two to three hours.

- Broad – spectrum antibiotic.

- Intramammary infusions.

Peracute or Gangrenous Mastitis:

The commonly causes Staph. aureus infection following a slight injury to the teat at any stage of lactation: occasionally E. coli.

Clinical Signs:

- Marked pyrexia in early stages, often progressing to a toxemia with subnormal temperature and death; may present as sudden death.

- Udder hard, hot, swollen and painful; minimal thin, bloody serous fluid from teat.

- Pain syndrome-teeth grinding, rapid pulse.

Treatment:

1. Peracute or gangrenous mastitis:

a. Economically, treatment is often not worthwhile. In a pet goat or where the goat is to be kept for breeding.

b. Intensive intravenous antibiotic therapy.

- Ampicillin 3my/kg.- Oxytetracycline 1-10 mg/kg.- Fluoroquinalones 1.25-2.25 mg/kg.

c. Non steroidal anti-inflammatory drugs will help decrease the production of inflammatory mediators and improve the clinical demeanour of the animal.

- Carprofen 1.4 mg/kg.- Flunixin meglumine 2 mg/kg.- Ketoprofen 3 mg/kg.- Meloxicam 0.5 mg/kg.

d. Intravenous fluid therapy, 100-200 mg/kg over 4-5 hours.

e. Good nursing rugs , heat and human company.

Acute Mastitis:

Caused by a number of different bacteria.

Clinical Signs:

- Pyrexia, anorexia, lethargy.

- Udder hard, swollen and painful.

- Milk yield decreased; milk consistency changed.

- Milk often thin and watery with clots.

Treatment:

a. Broad-spectrum antibiotics – parenteral and intramammary.

Broad-spectrum antibiotic:

- Cephalosporins.- Cloxacillin.- Amoxicillin/clavulinic acid preparations.

Intramammary:

- Cephacetrite sodium (Vetimast, Novartis).- Cefoperazone (Pathocef, Pfizer).

b. Oxytocin.c. Supportive therapy , as for peracute mastitis, if

necessary – intravenous fluids and non steroidal anti-inflammatory drugs.

Chronic Mastitis:

This develops from the acute form of the disease. It is manifested by hardness of the udder and by the presence of single or multiple abscesses within the gland and often the subcutis. The teat is sometimes swollen, and the teat canal may contain a hard core of inspissated pus. These changes are easily detected when the ewe is examined prior to mating

when the gland has involuted. (Single or multiple milk cysts may be mistaken for abscesses. Cysts occur most frequently ventrally in the mid-line; milk is readily aspirated from them.)

It become common to refer to mastitis observed at the premating examination of ewes as potweaning mastitis. The term embraced the notion that the several thousand ewes at the time of weaning and at regular intervals thereafter have shown that few new cases of mastitis develop after weaning. The great majority of cases of preweaning mastitis detected posweaning. They represent the sequelae of an acute mastitis that developed during lactation.

DIAGNOSISTo diagnose mastitis, it is necessary to learn how to distinguish between the symptoms of the various types of mastitis infection (see Tables 1 and 2 above). The key points to remember are as follows:

Monitor the milk: routine examination of the milk using a filter cup to extract the first three squirts before washing (before milking) is undoubtedly the best way to diagnose mastitis. The presence of lumps, flakes, blood, etc. must be watched for. Milk that is hotter than normal may be a good indication of a Staphylococcus aureus infection.

Palpate the udder: particularly after milking, when it is easy to detect swelling, and fibrous, hard or injured tissue.

Be attentive: to other more evident signs such as fever, redness, etc.

Since these symptoms are often absent, particularly in cases of subclinical, subacute or chronic mastitis, only half of all mastitis infections, at best, can be detected through observation. Some tests may therefore also be useful, notably cell counts, bacterial identification and the California Mastitis Test (CMT).

California Mastitis Test (CMT):

Introduction: The California Mastitis Test (CMT) is a rapid, accurate, animal-side test to help determine somatic cell counts (SCC). The term somatic cell is used to identify any cell in the body. With the CMT test, the somatic cells that are being measured are mainly neutrophils. Neutrophils are white blood cells that help the body fight infection and are present in increased numbers in the udder when the animal has mastitis. The CMT test was developed to sample individual udder halves to determine the presence of subclinical mastitis. The test can also be conducted on bucket and bulk tank milk samples to help determine somatic cell counts (SCC) of the entire herd.

California Mastitis Test

How to Perform the Test: A small sample of milk (approximately ½ teaspoon) from each teat is collected into separate compartments of a plastic paddle that has shallow cups marked A, B, C and D. An equal amount of CMT reagent is added to the milk. The paddle is rotated to mix the contents. In approximately 10 seconds, the score should be read, while continuing to rotate the paddle. Because the reaction disappears within 20 seconds, the test must be read quickly.

Clean each teat with alcohol. Squirt a small amount of milk from each teat into the appropriate section of the

paddle. 1/2 teaspoon of milk is sufficient.

Mix an equal ratio of reagent to milk. The paddle is rotated to mix the contents.

In approximately 10 seconds, read the score while continuing to rotate the paddle. This goat has a negative CMT score.

How to Read the Results: The CMT reagent reacts with the neutrophils, and the mixture thickens or gels in proportion to the amount of cells that are present. High levels of neutrophils indicate infection. To become accurate and consistent, practice this test on animals with a known SCC.

CMT Score   

Average Somatic Count (Cells per

milliliter)   

Description of reaction

N (negative)   

0-480,000    No thickening, homogeneous.

T (trace)    up to 640,000    Slight thickening. Reaction disappears in 10 seconds.

1    660,000    Distinct thickening, no gel formation.

2    2,400,000    Thickens immediately, begins to gel, levels in the

bottom of cup.

3    >10,000,000    Gel is formed, surface elevates, with a central peak

above the mass

Teepol test:

This test, used in France, is apparently indentical to the CMT(50). The reagent reacts with both epithelial cells and neutrophils. Test results with goat milk have been graded and interpreted as follows:

1. No or fine precipitation (as much as 500,000 cells/ml: nNormal.

2. granular precipitate (200,000 to 2,000,000 cells): mild irritation , as by improper milking.

3. filamentous precipitate (500,000 cells/ml): weakly pathogenic organism such as nonhemolytic staphylococcus.

4. viscous precipitate (more than 1,500,000 cells/ml): suggests presence of Staph. aureus.

Wisconsin mastitis test (WMT):

The Wisconsin Mastitis Test uses diluted CMT reagent. It is more objective than the CMT as the viscosity of the milk-reagent mixture is estimated from the volume remaining in a special tube after draining through a standard-size hole for 15 seconds. The WMT is considered to be DNA-specific. Results obtained using standard conversion factors for cow milk are similar to counts obtained by the fossomatic method.

Prevention and controlling mastitis:

1. Keep goats in a clean, dry environment, on a well balanced diet.

2. Goats are generally cleaner than cows, so it may not be necessary to wash udders before milking. However, udders should be washed if they are obviously dirty or if there is a problem with high bacterial cell counts in milk. Udder washing must avoid possible transfer of pathogens from goat to goat or from teat to teat:

- Use a disinfectant solution; washing with plain water will probably cause more problems than not washing at all.

- Use a spray system or wash and wipe with a single service paper towel soaked in disinfectant solution.

- Dry teats and udder thoroughly with separate disposable paper towel. Water running down the teats will drip into the bucket or be drawn into the liner during milking , carrying bacteria into the milk. Wet udders during milking easily transmit infection.

3. Routinely examine animals for mastitis at each milking use a strip cup or filter in the long milk tube to detect milk clots. During milking the udders should be examined for cleanliness , teat lesions and teat orifice abnormalities and changes in the udder tissue.

4. Use a postmilking teat disinfectant:

- To remove mastitis bacteria which could be transmitted from goat to goat by the milker or milking machine.

- To remove general bacteria from cut or sore teats.

The dip should be applied straight after milking has finished, whilst the teat canal is still open, so a small quantity of dip disinfects the epithelium of the teat canal. Unused dip should be discarded at the end of milking or as soon as it gets grossly contaminated.

5. Teat mastitis cases promptly, using the full course of treatment.

Treatment failures are usually due to:

- Using the wrong antibiotic.- Waiting too long before treatment.

- Using too low a dosage.

- Stopping treatment too soon.

- Presence of microorganisms that have become resistant to treatment.

- Failure of treatment to reach walled off sites of infection.

- Chronic cases with poor recovery chances.

6. Cull chronic or incurable cases.

7. Use preventative treatment at drying off (dry – goat therapy) where necessary dry goat treatments have at least twice the cure rates of treatments during lactation.

8. Keep records.

9. Maintain equipment in clean conditions; milking machines should be tested regularly.

References:

- Diseases of the goat (book author by John Matthews).- Goat medicine (book author by Mary C.Smith &

David M.Sherman).- Sheep and Goat Medicine (book author by

D.G.PUGH).

- Diseases of Sheep (book edited by W.B. Martin and I.D. Aithen).

- http://www.nnikolce.netfirms.com/mastitis_control.htm

- http://eap.mcgill.ca/Publications/EAP69.htm- http://www.infovets.com/demo/demo/smrm/

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