الفهرس يوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
Summary
The aim of this study was the evaluation of the commercially available coccidial vaccines by using body weight and feed conversion rate as the main parameter and intestinal lesions and oocyst out put as a secondary parameters .
In this study, a total of 540 broiler chickens were used as follow the first experiment consists of 90 birds was conducted to detect the efficacy of paracox ( a living attenuated vaccine ) at different ages, 30 birds for each age at 1, 3 or 7 days of age to detect the effect of age at vaccination.
The 2nd experiment consists of 90 birds and was conducted to evaluate the efficacy of “coccivac B” ( a living non attenuated vaccine contains 4 species of Eimeria and used for broilers ) and divided also into 3 groups each consists of 30 birds at 1, 3 or 7 days of old .
The 3rd experiment was conducted to evaluate the efficacy of “Coccivac D” ( a living non attenuated vaccine containing all species of Eimeria and used for layers and breeders ) This experiment was divided into 3 different ages 1, 3 or 7 days each age have 30 birds. Control birds a total of 270 birds was divided into 2 parts the unvaccinated unchallenged control birds.
Unvaccinated challenged birds of different ages and challenged as the vaccinated birds at 21 days old .
- All vaccinated birds were challenged after 21 days from vaccination .
This study revealed the following conclusions .
- All vaccinated birds could resist challenge at 21 days of age which revealed the efficacy of the vaccines used in this study .
- Performance of the vaccinated birds was not affected and was as good as unvaccinated unchallenged control birds .
- Unvaccinated challenged birds showed difference in performance lower than unchallenged unvaccinated birds and vaccinated birds as mesured by body weights and feed conversion rates .
- Birds vaccinated at 1-day-old could resist challenge and gave the same results of performance as vaccinated birds at older ages, indicating the efficacy of vaccination at 1-day-old chicks .
According to the fore mentioned findings and under the ideal conditions of the experiment it could be concluded that, the use of coccidial vaccines for vaccinating chickens at different ages was efficacious as measured by performance parameters and immunity levels. However it should be noted that these results obtained under ideal experimental conditions should not be compared with those obtained with commercially reared birds