Large-Scale Field Trials of an Eimeria Vaccine Induce Positive Effects on the Production Index of Broilers
The effectiveness of a commercial coccidia vaccine was evaluated in approximately 900,000 chicks reared on three open-broiler farms (J, S, JH farms) where coccidiosis is prevalent. The vaccine effectiveness after vaccination at one-day-old chicks was monitored using three parameters (lesion score, fecal oocyst shedding and production index) in nine trials, tested three times on each farm. Since the vaccine contains four species of Eimeria, E. acervuline, E. maxima, E. tenella, and E. mivati, lesion scores were confirmed in three different areas of the intestine. The average lesion score (n=240/farm) was 0.36 to 0.64 in the duodenal region, 0.30 to 0.39 in the jejuno-ileal region, and 0.18 to 0.38 in the cecal region. The average of fecal oocyst shedding(per gram) (n=240/farm) was 19.766 in JH farm, 100,100 in J farm, and 61,630 in S farm, showing big variation between farms. Compared to the production index (PI) of each farm's previous 9 or 10 trials, the JH farm increased by 2.45 PI, the J farm increased by 8.22 PI, and the S farm increased by 23.55 PI. These large-scale field trials have shown that coccidia vaccine plays positive roles on increasing PI, reducing the use of anticoccidials, and saving farmers' labor, resulting in increased economic value, feed savings, and reduction of antibiotic-resistant pathogens