Behavior of amitraz in cattle dipping baths.

Area of Science:

• Veterinary Entomology
• Agricultural Chemistry

Background:

• Cattle dipping baths are crucial for tick control in livestock.
• Amitraz and lime are common chemicals used in these baths.
• Understanding chemical settling and concentration changes is vital for effective parasite management.

Purpose of the Study:

• To investigate the settling rates of amitraz and lime in cattle dipping baths.
• To determine the impact of dipping numerous cattle on chemical concentrations.
• To assess optimal replenishment strategies for maintaining effective chemical levels.

Main Methods:

• Studied settling rates of amitraz (50% w/w wettable powder) and lime (Ca(OH)2) in cattle dips.
• Monitored chemical concentrations and bath volumes after dipping up to 1,200 head of cattle.
• Analyzed data from 796 baths to calculate concentration changes per 1,000 head.

Main Results:

• Both amitraz and lime settled, with rates decreasing as more cattle were dipped.
• Settling became negligible within an hour after stirring once 1,200 head were dipped.
• Baths could be cleaned by scooping sediment without significant chemical loss.
• No significant concentration changes occurred when bath volume decreased by 2,100 liters.
• Observed concentration changes: +0.00066% amitraz and -0.017% Ca(OH)2 per 1,000 head.
• Replenishment of 254 g amitraz per 700 liters closely matched manufacturer recommendations (250 g).
• Lime replenishment of 12.53 kg per 700 liters exceeded manufacturer recommendations (10 kg).

Conclusions:

• Amitraz and lime settling in cattle dips is minimal after extensive use, simplifying bath maintenance.
• Effective tick control can be maintained with reduced stirring frequency and by scooping sediment.
• Current replenishment guidelines for amitraz are accurate, but lime may require adjustment based on usage.