Effects of vaccination against coccidiosis in comparison to the use of dietary coccidiostats on the development and the performance of growing pullets and laying hens

2000 one-day old and non beak-trimmed chicks of H&N hybrid (white) were kept in an aviary system (Natura 400 AZ-187) which was divided into four groups of 500 animals each. Two groups were vaccinated with Paracox-8® on day 8 whereas the others were given a coccidiostat in the diet up to week 12. At the beginning of week 17, 1500 pullets (375 animals per unit) were moved to a layer shed equipped with an aviary system of Rihs Boleg II-type, which was also divided in four units.<br><br>During the rearing period up to day 111, vaccination with Paracox-8® was followed by small negative effects on animal weight (- 1.5 %), food consumption (- 0.4 %), weight uniformity (- 4.5 %) and mortality rate (3.5 vs. 2.5 %). Due to the vaccination, egg production of the later laying hens was slightly decreased (- 1 to – 2 %) and egg weight remained similar from week 21 to week 76. Food consumption and feed efficiency were impaired by 1.5 and 3 %, respectively. Mortality rate was increased by 5 % and reached a rather high level (0.9 % in four weeks). This result was mainly due to high losses from cannibalism. In week 3, high incidences of feather pecking were observed for the vaccinated pullets, but not for the coccidiostat-fed animals. For the rest of the trial, no differences in plumage condition could be seen any more.<br>It was concluded that Paracox-vaccination has probably no additional positive effects on development, performance and mortality rate of growing pullets and laying hens beside of its importance in coccidiosis prevention.