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Definition

Inflammation of mammary tissue.

Clinical Signs

May observe the following:

• A swelling or lumpy appearance in the area of mammary glands in lactating does.
• Area may be painful and or warm to touch.
• Poor appetite.
• Hunched posture.
• May have stopped allowing rat pups to nurse.

*Note: for additional information on recognizing various signs of pain or discomfort refer to: Signs of Pain In Rats.

Etiology

Mastitis can sometimes occur when a doe that is lactating fails to nurse her pups. This can be for reasons where the pups have been weaned to early, or if the pups have died.

With mastitis the mammary glands become engorged from the inability to nurse or express the milk. The milk then becomes stagnant which promotes the growth of bacteria, and sets up the conditions for tissue inflammation.

Additional factors that can lead to mastitis and introduce bacteria, is pups biting at the teat creating a wound entry, or the use of abrasive litters as nesting material. Another factor is a less than sanitary cage environment.

In septic mastitis some of the organisms that may be found are staphylococci, alpha-hemolytic streptococci, and E. coli. Progression of the infection and inflammation by these organisms may lead to the development of abscesses, or even to bacteremia and sepsis if left untreated.

Diagnostics

Obtain history.

Perform physical exam.

Obtain milk sample by fine needle aspiration for culture and sensitivity.

Treatment

Refer to the Rat Medication Guide for information on the following medications.

Place on broad-spectrum antibiotics such as: enrofloxacin, chloramphenicol, or tetracycline.
*Note: if rat pups not yet weaned avoid chloramphenicol and tetracycline.*

In the event of abscess development apply warm compresses 4 times a day to promote drainage and decrease swelling.

For an abscess that requires lancing, drain and flush the wound with normal saline (preservative-free sterile saline for contact lenses may be used, or for a saline solution at home mix 1 teaspoon of salt in 1 pint of warm water), and consider treating with trimethoprim-sulfa.

If sepsis and dehydration present institute warmed fluid therapy by SQ or IV.

Nursing Care

• Maintain clean cage environment.
• Provide clean bedding daily such as cloths or ink-free paper towels. Avoid litter-type bedding to prevent wound infection during healing process.
• Wash hands before handling and after caring for doe and pups.
• Provide additional warmth using a hot water bottle or heating pad, if needed, in order to maintain body temperature within normal limits. Use low heat settings and place under one half of cage to ensure rat does not become overheated or dehydrated.
• Provide high calorie foods and encourage fluids while nursing or recuperating.
• Try to refrain from having doe nurse if at all possible.
• Contact veterinarian if there are any further signs of infection: swelling, redness, or pain, or if there are signs of increased weight loss, lethargy, or changes in habits.

Outcome

• Swelling reduced.
• Infection resolved.
• Pain relieved.

Prevention

• Clean cage environment
• Wash hands before and after caring for doe and pups.

Posted on July 1, 2003, 10:29, Last updated on April 7, 2010, 13:21 | Reproductive