Effects of Various Infestation Levels of Cattle Lice (Mallophaga: Trichodectidae and Anoplura: Haematopinidae) on Feed Efficiency and Weight Gains of Beef Heifers

Abstract
Heifers with a heavy infestation of cattle lice (10 or more per 6.452 cm2 [1 in2] of Bovicola bovis (L.), Linognathus vituli (L.), and Solenopotes capillatus Enderlein) gained significantly less weight (0.09 kg [0.21 lb]/day) than heifers treated with stirofos or trichlorfon. No significant weight gain differences were found between heifers with a light to moderate or moderate to heavy infestation and treated heifers. Feed efficiency was not significantly affected by the three lice infestation levels evaluated in these trials.