Lice and mange populations peak in January and February.

The best way to avoid costly external parasite populations is to complete an annual whole-herd pour, preferably in late fall or early winter, advises Brian Miller, professional services veterinarian with Boehringer Ingelheim Vetmedica, Inc. Here are some recommendations for developing a wholeherd external-parasite control program:

• Dose properly. Incorrect dosing is the number one reason pour-on programs fail. Proper dosing depends upon the weight of the animal, so be prepared to reset the applicator gun as needed to ensure each animal receives the appropriate dose of pour-on.

• Apply properly. A proper application includes pouring along the back of the animal from the withers to the tail head.

• Pour new herd additions upon arrival. This would include springer replacement heifers, as well as bulls.

• Re-pour as needed. Animals that are the most severely infected with lice and mange at the time of the whole-herd pour should be re-poured three weeks later for optimal control.

For more information: Type “Control external parasites to maintain cow comfort” into the “Search” box at dairyherd.com