Effect of different vaccination programs on production parameters, carcass, leg bones, and digestive system characteristics of broilers.

The purpose of the present study was to compare the effects of two commercial vaccination programs using Prevexxion or Vaxxitek vaccines on production parameters, carcass weight and composition, and selected anatomical characteristics of Ross 308 broiler chickens. During the rearing period of broiler chickens, body weights were determined at 1, 10, 35, and 42 d of age, and feed intake and mortality of birds were recorded each day. On d 42 of the rearing period, 20 chickens were selected for dissection, 10 birds from each group. After slaughtering, the weight of the eviscerated carcass and the proportion of carcass elements, the lengths and diameters of individual intestinal segments, the weight of selected internal organs, and the dimensions of the femur and tibia were determined. The Prevexxion vaccination program had a positive significant effect on eviscerated carcass yield, dressing percentage, breast meat, wing and carcass remains content, as well as duodenum length, proventriculus content of slaughter weight and smallest breadth of the corpus of tibia bone. Broiler chickens treated with Prevexxion vaccines had higher European Production Index. The results indicate that Prevexxion vaccines have a more favorable effect on the production performance and slaughter characteristics of Ross 308 broiler chickens than with the use of Vaxxitek vaccines.