Production losses in laying hens during infestation with the poultry red mite Dermanyssus gallinae

Figures & data

Figure 1. Infrastructure of the layer hen compartments and average MMS scores of the units at onset of fluralaner treatment (*).

*Bold lines indicate the separate compartments, dashed lines the observational units.^#Mentioned figures: average MMS scores (Cox et al., 2009) in the 48 different units, measured immediately prior to onset of treatment.

Table 1. Performance changes observed after treatment with fluralaner in PRM-infested and non-infested units of laying hens, housed in enriched cages ⁽*⁾.

Production parameter	Infestation level at onset of treatment			P-values obtained with tests of
	Not visually infested (n = 14 units)	Low – moderate (n = 9 units)	High (n = 9 units)	Kruskal–Wallis	Dunn^C
Laying percentage^a	+0.66	+0.75	+1.46	0.008	0.006
Egg weight^a	−0.37	−0.11	+0.50	0.028	0.011
Egg mass^a	+0.33	+0.67	+1.86	0.006	0.005
First-choice eggs^b	−0.30	−0.35	+11.91	0.008	0.002
Feed intake^a	−0.38	−1.19	+2.76	0.018	0.047
Feed conversion^a	−0.85	−2.14	+0.49	0.294
Body weight^a	+2.52	+4.18	+3.02	0.713
Hen mortality^b	+0.04	+0.02	−0.01	0.610

*Average changes within the units, observed between the 4-week period posttreatment and the 4-week period pre-treatment.

^aValues calculated as percentage difference from production standard values for Dekalb White and Isa Brown hens kept in cage systems (Hendrix Genetics, 2018a, 2018b).

^bValues expressed as absolute figures since production standard values are lacking (Hendrix Genetics, 2018a, 2018b).

^cDunn's test (Kutner et al., 2005b) performed post-hoc when tests of Kruskal–Wallis revealed P-values < 0.05, comparing observations from units with a high level of PRM infestation to those of non-infested controls. P-values < 0.05 indicate significant differences.

Cox, M., De Baere, K., Vervaet, E., Zoons, J. & Fiks-Van Niekerk, T. (2009). Red mites: monitoring method and treatment. In S. Barbieri, V. Ferrante, S. Lolli, & G. Sayegh (Eds.). Proceedings of the 8th European Symposium on Poultry Welfare (p. 83). Cervia, Italy.

 Google Scholar

Hendrix Genetics. (2018a). Dekalb White product guide, cage production system. Retrieved from https://www.dekalb-poultry.com/en/product/dekalb-white/.

 Google Scholar

Hendrix Genetics. (2018b). Isa Brown product guide, cage production system and alternative production systems. Retrieved from https://www.isa-poultry.com/en/product/isa-brown/.

 Google Scholar

Kutner, M.H., Nachtshein, C.J., Neter, J. & Li, W. (Eds). (2005b). Chapter 18: Anova diagnostics and remedial measures. In Applied Linear Statistical Models 5th edn (pp. 775–811). New York: McGraw-Hill/Irwin.

 Google Scholar