Assessing the efficacy and zootechnical performance in laying hens after administration of a 1% aqueous solution of fluralaner (Exzolt) for treating natural infestation by Menacanthus cornutus

A brood of laying hens infested with the lice Menacanthus cornutus (Phthiraptera: Menoponidae) evidenced itching, irritation, and damage to their zootechnical performance. A study was conducted to evaluate the zootechnical performance and infestation control using a 1% solution of fluralaner in a brood of white laying hens infested naturally with lice. The experiment was carried out using 10,560 naturally infested chickens divided into 2 groups: a treatment group of animals that received a 1% solution of fluralaner in drinking water, at a dose of 0.05 mL/kg of body weight, in 2 administrations, 7 d apart; and a control group of infested and untreated chickens. The groups of chickens were followed for 120 d to evaluate the score of infestation and zootechnical performance. It was observed that birds in the treatment group became free of lice infestation 7 d after the administration of the first dose of a 1% solution of fluralaner. For up to 120 d after the experiment was initiated, there was no evidence of subsequent lice infestation, while continued infestation with all life stages of lice (adults, young, or eggs) was evident in the untreated control group, remaining stable during all evaluations performed. The birds in the treatment group showed improved zootechnical performance when compared to a 9.94% egg production decrease in the control group. The feed conversion and egg mass data showed statistically significant differences between the 2 groups. This study allows us to conclude that treatment with a 1% solution of fluralaner effectively controlled Menacanthus cornutus lice infestation and promoted recovery of egg production in a brood of laying hens treated with the test formulation.