Main content

Live Eimeria Vaccine use in Commercial Pullet Rearing: Environmental Influences on Vaccination Success

Show full item record

Title: Live Eimeria Vaccine use in Commercial Pullet Rearing: Environmental Influences on Vaccination Success
Author: Price, Kayla
Department: Department of Pathobiology
Program: Pathobiology
Advisor: Barta, John
Abstract: Coccidiosis is a common disease of poultry caused by Eimeria species. Live Eimeria vaccination protects against coccidiosis through an initial vaccine dose of infective oocysts enhanced through low level, fecal oral transmission, termed “cycling”. Vaccination is best accomplished with uniform vaccine administration and environmental conditions that promote cycling. Commercial vaccines are administered by spray cabinet using coloured droplets delivered to trays of chicks. Uniformity of vaccine ingestion was tested following spray vaccination; 53 of 59 tested pullets were shedding oocysts (90% coverage) but the oocyst numbers each ingested was widely variable. Hatchery vaccinated pullets may not be placed for a day or more so delayed access to feed post vaccination was examined. Vaccinates prevented access to feed for 24hr had peak oocyst output two days later than immediately fed birds but the number of oocysts shed following vaccination were not impacted significantly. Studies exploring environmental factors influencing vaccination success focused on replacement layer pullets in conventional cages. Cage modifications were tested for their ability to enhance within cage oocyst cycling and improve vaccine efficacy. Pullets vaccinated by gavage were reared with 0%, 20%, 40% or 60% of the cage floors covered with biodegradable material (lasting ~5 weeks). Covering 40% of the cage floor increased both intensity and duration of within cage oocyst cycling and significantly improved live vaccine efficacy (comparing body weights, oocyst shedding and lesion scores post challenge) with negligible impact on animal welfare. Three experiments tested if 40% cage floor coverage could enhance cycling and vaccine efficacy with non-uniform vaccine dosing (by gavaging subsets of pullets or by using spray vaccination). Covering 40% of the cage floors increased within cage oocyst cycling and significantly enhanced vaccine efficacy even following non-uniform dosing. Finally, one trial failure demonstrated unequivocally that appropriate relative humidity in the barn is critical for vaccination success. Collectively, this research has demonstrated that live Eimeria vaccines can be used effectively with caged reared pullets. Successful vaccination can be achieved by introducing a minor environmental modification (40% cage floor coverage with folded chick paper) and maintaining barn environments (adequate humidity) that support parasite cycling among pullets, even if initial vaccination was non-uniform.
Date: 2014-12

Files in this item

Files Size Format View
Price_Kayla_201412_PhD.pdf 3.170Mb PDF View/Open

This item appears in the following Collection(s)

Show full item record