(273) Mastitis denotes inflammation and infection of the mammary glands. It is primarily a condition seen in the lactating sow. Nevertheless it can be a problem in the dry period with new cases occurring within two days of weaning. If left untreated it can become chronic with thick fibrous scar tissue and large lumps which ultimately may ulcerate to the surface. Chronic mastitis may occur at weaning time when the udder is dried off, the gland having become infected in lactation. The disease can be caused by a number of different bacteria including streptococci, staphylococci, E. coli, klebsiella, pseudomonas and actinomyces.

Clinical signs

Acute disease
These are seen within 2 to 4 days of weaning. The infected glands are enlarged red and painful to pressure and the skin overlying is blanched or discoloured. The temperature is usually raised and the sow is off her food. In severe infections toxins are produced and sows may die within 24 hours.

Chronic disease
If there is a poor response to treatment or disease has not been recognised in lactation, the gland may be enlarged, often with fibrous tissue and small multiple abscesses that may ulcerate to the surface. Invariably at this stage there is permanent damage and if several mammary glands are affected the sow should be culled.

Diagnosis

This is determined by visual evidence of swellings and hard lumps in the mammary gland. The sow's udder should be examined routinely at two days after weaning and also while the sow stands at mating, to look and feel for chronic mastitis.

If the prevalence is more than 2% of the dry sow population then an investigation should be carried out to assess the reasons why and to determine where the mastitis is starting. This could be in the immediate post farrowing period, during lactation or at weaning time. Preventive measures would then be carried out relative to that period.

Treatment

• This should follow the general guidelines as for mastitis in the lactating sow in chapter 8. If the mastitis is being initiated from point of weaning a long-acting antibiotic should be given on the day of weaning .