C. Delarosa et al., VACCINATION SCHEDULES TO RAISE ANTIBODY CONCENTRATIONS AGAINST EPSILON-TOXIN OF CLOSTRIDIUM-PERFRINGENS IN EWES AND THEIR TRIPLET LAMBS, Journal of animal science, 75(9), 1997, pp. 2328-2334
The objective of this experiment was to compare vaccination schedules
for ewes and their lambs to raise antibody concentrations to epsilon-t
oxin of Clostridium perfringens, the causative agent of enterotoxemia.
Half of 200 Finnsheep x Dorset ewes were vaccinated with C. perfringe
ns type D toroid vaccine 3 wk before lambing. Serum samples were obtai
ned from 20 ewes that were to be vaccinated and 20 ewes that would rem
ain unvaccinated before treatment and at wk 2, 1, and 0 before the sta
rt of lambing. Antibody concentrations in sera of unvaccinated ewes re
mained at 2 IU/mL, but they peaked in vaccinated ewes at 15 IU/mL by w
k 1 before lambing. Lambs from each of the first 13 and the first 14 s
ets of triplets from vaccinated and unvaccinated ewes, respectively, r
eceived one of three vaccination treatments: no vaccine (control), vac
cination on d 1 and 21 of age, or vaccination on d 21 and 42 of age. A
ntibody concentrations declined in sera of vaccinated ewes from 8.5 IU
/mL immediately after lambing to 3 IU/mL 12 wk later. Vaccination of l
ambs did not increase sera antibody concentration. However, prepartum
vaccination of ewes significantly increased lamb antibody concentratio
ns (19 IU/mL) compared with lambs reared by unvaccinated ewes (2 IU/mL
). Vaccination of ewes resulted in lambs with higher antibody concentr
ations until wk 10 postpartum. Concentrations declined to .6 IU/mL in
all lambs at 12 wk. Because concentrations of .2 IU/mL may be protecti
ve, these results indicate that vaccination of ewes before lambing imp
arts passive protection in lambs to 12 wk of age, whereas vaccination
of young lambs provides no added protection.