This syndrome usually occurs within three days of farrowing and is characterized by inadequate milk production. Although hypogalactia is the most consistent sign, mastitis, fever, vaginal discharge, listlessness, weakness, anorexia, sternal recumbency and refusal by the dam to permit nursing by the piglets seem to be commonly present in affected sows. Dams usually recover within a few days to two weeks. Piglets are at high risk of dying from starvation unless cross-fostered or supplemented with other feed. Although the cause(s) is unknown, many risk factors have been associated with hypogalactia. These include lack of nursing stimulation (too few pigs or small/weak pigs), bacterial metritis, mastitis, mammary edema from errors in ration formulation, confinement with little opportunity for exercise, poor feeding management, constipation, obesity, moldy feeds, and poor sanitation in the farrowing environment.
Mastitis, often clinically undetected, is likely responsible for many cases of hypogalactia. Endotoxin from various Gram-negative bacteria, especially Escherichia coli, may be the basic cause of many cases of mastitis. Suppression of prolactin by endotoxin from any source results in less than normal milk production. The prevalence of MMA has decreased markedly in the last several decades with the use of modern sanitary and slatted flooring. Most problems with hypogalactia can be solved through management with careful attention to sanitation and the sow’s exercise, nutrition, and body condition.