Vaginal Microecology and Vulval Discharge in Swine

This article reviews current knowledge concerning the occurrence of vulval discharges in sows. Both the role of the vaginal flora and the management practices on the herd are emphasised. It appeared that the vaginal flora changes with the reproductive stage of the sow, and that many of the bacteria of the vaginal flora are similar to those frequently reported in clinical cases of the vulval discharge syndrome. Factors that contribute to a high contamination of the urogenital tract of sows, such as low hygiene standards and poor housing conditions are important risk factors for the disease. Poor management of the boar and insufficient oestrus detection also increase the risk of infection. The cyclic variation of uterine defence capacities throughout the reproductive cycle plays an important role in the pathogenesis of vulval discharge. Defence mechanisms decrease towards the end of oestrus and at onset of metoestrus i.e. when oestrogen levels have become low and when progesterone levels increase. Criteria that can be used to discriminate between physiological and pathological discharge, and that permit to pinpoint the exact infection site in case of a pathological discharge, are discussed. There is no uniform treatment and the results of antimicrobial therapy are often disappointing. Prevention rather than treatment should be encouraged. Preventive measures are largely based on minimising or eliminating the different risk factors for the disease.