This experiment aimed to determine if spraying intestinal sporulated Eimeria oocysts in an empty nest box will give natural immunity to growing bunnies against serious invocation comparing to the effect of rabbit ration pellets admixed with anti-coccidian powder under Egyptian practical conditions. Twenty five coccidia free New Zealand White (NZW) does with their offspring were randomly divided equally into 5 groups (G1 to G5) with mean weight of 455.2±10.69 gram/bunny. At day 25 of bunnies' age, 15 ml of saline contain equal mixed of four intestinal Eimeria spp. oocysts (40, 400 or 4000 per bunny) were sprayed in empty nest boxes of groups 1, 2 and 3 respectively (vaccination). At day 35 bunnies of all five groups were challenged orally with 5 ml of saline contained 5000 of equal mixed inoculation Eimeria spp. oocysts (challenge), the experiment ended at day 45 of bunnies' age. All groups were fed to ad libitum with a rabbit commercial pellet ration, but only group 5 ration was supplemented with anti coccidian powder.
Results obtained indicated that post vaccination high oocysts excretions were observed combined with mortality rates and diarrhea in G1, G2 and G3.
Post challenge high oocysts excretions were observed combined with high mortality rates and diarrhea in G1, G2 and G4 (G4 was the highest), while G3 and G5 had no oocysts excretions.
Feed intake and feed conversion between days 35-45 of age had significant differences between some groups where G5 was the best.
Conclusively, the results make us to advice to keep using the anti-coccidian in ration until we solve the problem of mortality post vaccination and to do more studies to confirm or deny our present results under the Egyptian conditions.