EPIDEMIOLOGY AND MANAGEMENT OF SELECTED SWINE REPRODUCTIVE DISEASES

The epidemiology of selected swine reproductive diseases is discussed in relation to herd size and management systems. The reproductive dise ase agents of major importance in the U.S. are porcine parvovirus, Lep tospira spp., pseudorabies virus, swine influenza virus, and porcine r eproductive and respiratory syndrome virus. In sow herds, each reprodu ctive disease expresses clinical signs specific to that disease depend ent on herd size and management systems, but sick sows, conception fai lures, resorption of fetuses and abnormal returns, abortion, birth of litters with few pigs, premature births, presence of excessive stillbo rn or mummified fetuses at term, and birth of weak pigs are the signs usually observed. Dependent on the disease present, individual sows ex press clinical signs related to the time during the reproductive cycle they are infected. The clinical expression of these diseases in indiv idual sows and in herds can be used as an aid to diagnosis. Vaccines a re available for all the diseases listed, but protocols for effective use of vaccines for influenza and porcine reproductive and respiratory syndrome are subject to further investigation.