In lactating or weaned sows, inflammation of a single mammary gland is common. Such uniglandular inflammations are more often noticed in old sows.
Etiology and Pathogenesis
The microorganisms involved are the same as those in acute multiglandular mastitis (see Cystic Ovary Disease: Etiology and Pathogenesis). Sometimes only 1 or 2 mammary glands are affected; the cause should be identified. Traumatic lesions or inaccessibility of teats to piglets are common. Piglets suckling inguinal mammary glands of old sows are often unable to reach the teat during the phase of milk ejection. Usually, piglets have selected a specific gland by 24 hr after birth. A piglet suckling a teat affected by acute uniglandular mastitis will show growth retardation, while littermates remain normal. Milk secretion may be restricted by acquired problems of mammary conformation (as in old sows), traumatic lesions, and other teat abnormalities. Teat lesions may have developed during the previous lactation, the previous weaning-to-estrus interval, or the previous gestation.
The integrity of the mammary gland should be checked before each farrowing. Except for cases associated with inaccessible teats, risk factors involved in the development of blind teats should be identified. Traumatic teat lesions can be the consequence of injuries induced by piglets or other sows, or by slipping on slatted floors, etc. Unfortunately, these primary lesions often go unnoticed until several weeks or months have passed.
Treatment and Control
The affected gland is lost for the current lactation and sometimes for the next lactation. During subsequent lactations, the number of nursing piglets should be limited, or the sow should be culled.
Last full review/revision July 2011 by Guy-Pierre Martineau, DVM, DECPHM