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.

摘要

2000 one-day-old beak-trimmed chicks of H&N hybrid (white) were kept in an aviary system (Natura 400 AZ-187) and were divided into 4 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 into 4 units. Minor negative effects on animal weight (-1.5%), food consumption (-0.4%), weight uniformity (-4.5%) and mortality rate (3.5 vs. 2.5%) were observed following vaccination with Paracox-8 during the rearing period up to day 111. Due to vaccination, egg production of the later-laying hens was slightly decreased (-1 to -2%) although egg weight remained similar from week 21-76. 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 was mainly due to high losses from cannibalism. In week 3, high incidences of feather picking were observed in the vaccinated pullets, but not in the coccidiostat-fed animals. For the rest of the trial, differences in plumage condition were no longer seen. It was concluded that, besides its importance for the prevention of coccidiosis, Paracox vaccination has probably no additional positive effects on development, performance and mortality rate of growing pullets and laying hens.