SUMMARY Three transmissible gastroenteritis (tge) vaccines were tested, an inactivated virus vaccine for intramuscular (i.m.) use, a modified live-virus vaccine for i.m. use, and an inactivated virus vaccine for intramammary use. All 3 vaccines were considered satisfactory for safety, but only the modified live-virus vaccine for i.m. use was considered sufficiently efficacious to warrant licensing. In the experiment to evaluate the currently licensed modified live-virus tge vaccine for i.m. use, there were 26 sows used. Ten were vaccinated twice according to label directions, 6 were given virulent tge virus orally, and 10 were not given vaccine or virus. At 72 hours postpartum, all but 5 pigs were removed from each sow. Each of the 5 nursing pigs was then given 100 median pig lethal doses (pld50) of virulent tge virus, by oral administration. Criteria for evaluating results were based on pig morbidity, survival rate, and weight gains at 6 weeks of age. The morbidity rates were 100% for pigs nursing sows vaccinated with the experimental vaccine and for pigs nursing nonimmune control sows, whereas the morbidity rate was 14% for pigs nursing sows exposed to virulent tge virus. The survival rate was 62% for pigs nursing sows given the experimental vaccine and 28.9% for the pigs nursing the nonimmune control sows. The survival rate of pigs nursing sows exposed to the virulent virus was 100%. The average weight gain per pig at 6 weeks of age for pigs nursing sows given the experimental vaccine was 17.16 lb. (7.8 kg.), 14.9 lb. (6.8 kg.) for the pigs nursing nonimmune control sows, and 19.8 lb. (9 kg.) for pigs nursing sows given virulent tge virus.
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T. W. Tamoglia (1972) studied this question.