The Effect of ClariFly® Larvicide in Purchased Feed on Fly Populations on Dairy Farms in 2008 and 2013

• Published in: Journal of animal science Vol. 96; p. 39
• Main Author: Mooney, C S
• Format: Journal Article
• Language: English
• Published: Champaign Oxford University Press 01-03-2018
• Subjects: Annual variations; Avoidance behavior; Calves; Cattle; Composition effects; Control methods; Dairy farms; Data processing; Diflubenzuron; Experimentation; Farms; Feeds; Grain; Housing; Insects; Milk; Populations; Seasonal variations
• ISSN: 0021-8812; 1525-3163

Reducing fly populations on dairy farms can increase cow comfort and reduce the spread of disease pathogens. The objective of these experiments was to determine the effect of inclusion of diflubenzuron larvicide (ClariFly®) in feeds consumed on fly populations on dairy farms. In 2008 and 2013, twelve dairy farms in Vermont and New York were assigned to 6 blocks by herd size, geographic location and lactating herd housing. On treated dairy farms, ClariFly® was added to all purchased feeds to achieve an intake of 0.10 mg diflubenzuron/kg BW/d. In 2013, ClariFly® was also added to milk or milk replacer fed to calves. Control dairy farms were permitted to use all fly control methods other than "fed-through" products. Each dairy was visited biweekly starting in June. Fly populations were quantified with fly speck count on 3 × 5 notecards, collection of flies on a sticky trap during walk on predetermined path, flies on-calf counts, and observations of fly avoidance behavior. Data were analyzed as a randomized block design with main effects of random block, treatment, period, and treatment by period interaction in MIXED procedure of SAS. Period effects (P < 0.01) reflected normal seasonal changes in fly population. With treatment in 2008 and 2013, fly populations decreased in the lactating herd housing when compared to control (P < 0.05) but an interaction of treatment and period increased difference in summer (P < 0.07). In calf housing, treatment did not decrease fly populations measured in 2008 likely related to limited intake of purchased grain during first weeks of life (P > 0.10). In 2013 with ClariFly® included in milk or milk replacer, fly populations decreased in calf housing (P < 0.001). Milk yield and composition effects were mixed across years and more defined experimentation is needed before firm conclusions can be drawn about cause and effect.