Hardened lump in the udder tissue - Atlas of swine pathology
Where: genitourinary system, mammary gland
Possible causes: Other
Hardened lumps in the udder tissue, especially in the rear half of the udder, are commonly seen in sows and are termed 'actinomycosis'. Actinomyces suis is the most common cause but other bacteria may be involved.
Discrete swellings are usually first seen after weaning and in the first month after service and appear to be associated with damage and fight wounds to the udder. The condition appears due to heavy contamination in the weaned sow pen. Other causes could be related to an infectious agent penetrating the udder during the previous lactation as a result of teeth damage, but only becomes apparent once the milk producing tissue atrophies after weaning. The initial swelling is hard and painless and there is no systemic illness.
In some cases the hardened lump remains dormant and is of little consequence, although there is probably a reduction in milk production for the affected glands. As the sow approaches her next farrowing, the lesions can become active, increasing in size and ulcerating such that purulent material exudes from the ulcer.
