|Title||Comparison of Eimeria Infection Dynamics between Broiler Flocks with a Conventional or On-farm Hatching System.|
|Author(s)||Velkers, Francisca; Jong, I.C. de; Ven, Lotte van de; Reep, L. Van de; Stegeman, A.|
|Source||In: Proceedings of the XXthe Veterinary Poultry Congress, Edinburg. - - p. 197 - 197.|
|Event||XXthe World Veterinary Poultry Asoociation Congress, Edinburgh, Edinburgh, 2017-09-04/2017-09-08|
LR - Animal Behaviour & Welfare
|Publication type||Abstract in scientific journal or proceedings|
|Keyword(s)||Broiler Chickens, Coddidiosis, Eimeria, Enteric Disease, On-farm hatching|
|Abstract||An increasing trend in Europe is placing 18 days incubated eggs on trays in broiler houses for on-farm hatching. Chicks are not transported and have immediate access to food and water, which promotes early intestinal tract and immune system development. It was hypothesized that these physiological effects may affect the response to intestinal infections. Moreover, on-farm hatched chicks may be exposed to environmental Eimeria oocysts earlier than hatchery chicks. Therefore we compared Eimeria infection dynamics for in hatchery (R) and on-farm hatched (F) Ross 308 broilers in two field studies on commercial broiler farms and in one study in an experimental facility.
In field study 1, a poultry house was divided in a part with F and R hatching for two rounds. Ten flocks on four farms were included in field study 2 with on each farm F flocks and R flocks originating from the same parent flock. In study 3, four groups of F and R broilers were placed in experimental pens, each with 1150 birds from the same parent flock. From the second week of life onwards, oocyst excretion in faeces (OPG = oocysts per g), collected in weekly (study 2) or biweekly (studies 1 and 3) intervals, was determined with the McMaster counting technique. In both field studies an Eimeria-species specific OPG was determined with qPCR (GD Deventer, the Netherlands) on weekly pools of colonic and caecal faeces collected three times per week. Lesion scores for E. acervulina, E. maxima and E. tenella were determined during post-mortem examinations of five to six randomly selected birds on one to three occasions per production round from the third week of life onwards. Use of coccidiostats, antibiotics and production performance was recorded.
Results of qPCR showed that E. acervulina, E. tenella (studies 1 and 2) and E. maxima (study 2) were detected, without differences in species distribution between F and R flocks. In study 3, where qPCR results were not available, lesion scores indicated presence of E. acervulina and E. maxima, but not E. tenella in both F and R flocks. In all studies lesion scores were generally mild and not significantly different between F and R flocks. Oocyst excretion patterns throughout the production period were similar for F and R flocks in study 1, but in study 2 F flocks on average showed a later excretion peak (R peaked between day 22-28 and F between days 22-28 or 28-34). In study 3 oocyst output dynamics were comparable in F and R pens. In this study oocyst excretion did not reach a clear peak by the end of the round at day 40, due to a late (day 33) start of excretion. OPG determined by qPCR and the McMaster technique in studies 1 and 2 gave similar results. Production performance could not be compared between F and R flocks in the field studies, due to differences in disease occurrence and antibiotic treatments.
Only small differences in the course of Eimeria infections were detected, but the number of flocks was too small to draw accurate conclusions about effects of hatching system on coccidiosis and how this affects production performance. Small differences in infection dynamics, e.g. time of peak excretion, may affect body weight at slaughter or influence opportunities for secondary infections. Therefore, if more commercial on-farm hatching and comparable reference flocks become available, further research is warranted.