EFFECT OF ESCHERICHIA-COLI J5 VACCINE AND INTRAMAMMARY CHALLENGE WITHLIVE ESCHERICHIA-COLI IN LACTATING DAIRY GOATS

Ten lactating goats were randomly assigned to two groups of five vacci nates and five controls. The vaccine was a heat-killed rough mutant st rain of Escherichia coli (E, coli) J5 containing 1.5 X 10(9) organisms per mi in incomplete Freund's adjuvant. The vaccinated group received three 1 mi doses of vaccine 14 days apart. The control group received three 1 mi doses of incomplete Freund's adjuvant in a similar regimen . Seventeen days after the third dose of vaccine or Freund's adjuvant all goats were intramammarily (IM) challenged with 15 colony forming u nits of live virulent E. coli into each teat. Severe clinical signs su ch as depression, anorexia and prolonged recumbency were observed afte r challenge in the control goats. In vaccinated goats the signs were l ess severe, although they had some depression and anorexia for 36 h po st-challenge. Body temperature of the animals in both groups increased after challenge with live E. coli, However, peak temperature was sign ificantly lower in vaccinated goats compared with control goats. E. co li count in the milk of vaccinated goats was significantly lower compa red with control goats after IM challenge. E, coli from the milk of va ccinated goats was removed more rapidly compared with control goats. S erum J5 antibody levels of vaccinated goats were significantly higher on Days 14, 21, 28, 35 and 42 after vaccination. After challenge a sig nificantly higher serum J5 antibody level was observed in vaccinated g oats at 12, 24, 48 and 72 h. Milk anti-J5 antibody levels were signifi cantly higher on Day 28 after vaccination in vaccinated goats. This st udy concludes that J5 vaccine provides partial protection against E. c oli intramammary challenge and goats can be used as an economic model for studying bovine mastitis.