Bacteriologic study of sow agalactia.

Necropsy of 13 agalactic and 11 normally lactating sows at 1 to 2 days after parturition revealed that 7 of the agalactic and 4 of the clinically normal sows had lesions of mastitis. Escherichia coli, Streptococcus equisimilis, and Staphylococcus epidermidis were the predominant organisms isolated. The organisms were isolated as pure and as mixed cultures and all 3 were isolated from normal appearing, as well as mastitic, glands. Pure culture isolation of E. coli (44 gland segments) was significantly associated with microscopic lesions of mastitis, regardless of the number of colonies isolated, whereas pure culture isolation of Streptococcus equisimilis or S epidermidis in low to moderate numbers was not. Isolation of large numbers of beta-hemolytic streptococci (2 gland segments) or of S epidermidis (6 gland segments) was associated with microscopic evidence of mastitis. Cultural examination of uterus and cervix revealed 5 isolates of strict anaerobic bacteria, all different species, from 4 of the 24 sows. Culture of 2 mammary glands from each sow revealed no strict anaerobes. Phase-contrast microscopic examination of specimens from mammary glands, uterus, and cervix of each sow revealed no spirochetes. Attempts to isolate mycoplasmas and chlamydiae from mammary gland, uterine tube (fallopian tube), uterus, cervix, and urethra of the 24 sows were negative. The evidence confirms previous reports that coliforms are the most significant bacteria in mastitis of the sow.